Optical system, imaging module, and electronic device

Abstract

The present invention discloses an optical system, an imaging module and an electronic device. The optical system includes a plurality of lenses, and the plurality of lenses are successively arranged from the object side to the image side as a first cemented lens group, a second lens, a third lens, a fourth lens and a fifth lens. The first cemented lens group includes an object-side lens and an image-side lens formed by cementing. The object-side lens is the lens in the first cemented lens group close to the object side, and the image-side lens is the lens in the first cemented lens group close to the image side. The third lens has a negative optical power, the fourth lens has a positive optical power, and at least one of the object side surface and the image side surface of the fourth lens has an inflection point. The fifth lens has a negative optical power; 1.5 < Nds2 < 1.66, 1.5 < Nds3 < 1.66, where Nds2 is the refractive index of the object-side lens and Nds3 is the refractive index of the image-side lens. According to the optical system of the embodiment of the present invention, it has excellent optical performance, can achieve excellent small aberration effect, and meets the requirements of good imaging quality for high pixels.

Description

Technical Field

[0001] The present invention relates to the field of optical imaging technology, and in particular, to an optical system, an image pickup module, and an electronic device. Background Art

[0002] In related technologies, intelligent electronic products usually have a photographing function, and consumers' requirements for the photographing effect are also getting higher and higher. With the development of intelligent electronic products, the proportion of the camera on the screen is getting smaller and smaller. The camera module needs to be encapsulated in a very small area of the screen, which is closely related to the design of the lens shape, and the requirements for the lens specifications are also getting higher and higher. With the improvement of the performance and the increase in the size of common photosensitive elements such as charge-coupled devices (CCDs) or complementary metal oxide semiconductors (CMOSs), the number of pixels of the photosensitive element increases and the pixel size decreases, which puts forward higher requirements for the miniaturization characteristics of the imaging lens. Therefore, how to meet the miniaturization design while ensuring the high imaging quality of the lens has become the research and development direction in the industry. Summary of the Invention

[0003] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, an object of the present invention is to propose an optical system, which has the characteristic of a small head aperture and can meet the requirements of a miniaturized lens while ensuring high imaging quality.

[0004] The present invention also proposes an image pickup module.

[0005] The present invention also proposes an electronic device.

[0006] The optical system according to the first aspect embodiment of the present invention includes a plurality of lenses, the plurality of lenses are a first cemented lens group, a second lens, a third lens, a fourth lens, and a fifth lens arranged in sequence from the object side to the image side. Among them, the first cemented lens group includes an object-side lens and an image-side lens formed by cementing. The object-side lens is the lens in the first cemented lens group close to the object side, and the image-side lens is the lens in the first cemented lens group close to the image side. The third lens has a negative optical power, the fourth lens has a positive optical power, and at least one of the object side surface and the image side surface of the fourth lens has an inflection point. The fifth lens has a negative optical power; the optical system satisfies the following conditional formula: 1.5 < Nds2 < 1.66, 1.5 < Nds3 < 1.66, where Nds2 is the refractive index of the object-side lens of the first cemented lens group, and Nds3 is the refractive index of the image-side lens of the first cemented lens group.

[0007] The optical system according to an embodiment of the present invention can be made compact and simple in structure by providing a cemented lens group, reducing the volume, which is beneficial to shortening the total length of the optical system, meeting the requirements of miniaturization, and facilitating assembly at the same time, improving the assembly yield of the optical system; by providing an inflection point on the surface of the fourth lens, it is beneficial to correct the distortion generated by the optical system, and can reasonably control the overall aberration of the optical system to achieve good imaging quality; by reasonably configuring the optical power of the lenses, the imaging quality is further improved; by reasonably configuring the refractive indices of the object-side lens and the image-side lens, the optical system can have excellent optical performance, achieve excellent small-aberration effects, and meet the requirements of good imaging quality for high pixels.

[0008] For the optical system according to an embodiment of the present invention, the cemented surface of the object-side lens and the image-side lens is convex, or the cemented surface of the object-side lens and the image-side lens is concave.

[0009] For the optical system according to an embodiment of the present invention, both the object side surface and the image side surface of the fourth lens are aspherical surfaces.

[0010] For the optical system according to an embodiment of the present invention, the optical system satisfies the conditional formula: 0.45 < CTs2 / SD11 < 1.1, where CTs2 is the thickness of the object-side lens on the optical axis, and SD11 is the effective semi-aperture of the object side surface of the first cemented lens group.

[0011] For the optical system according to an embodiment of the present invention, the optical system satisfies the conditional formula: 6.5 < TTL / CTs3 < 13.0, where TTL is the distance from the object side surface of the first cemented lens group to the imaging surface of the optical lens on the optical axis, and CTs3 is the thickness of the image-side lens on the optical axis.

[0012] For the optical system according to an embodiment of the present invention, the optical system satisfies the conditional formula: 0.3 < f1 / |R3| < 3.0, where f1 is the combined focal length of the first cemented lens group, and R3 is the curvature radius of the cemented surface of the object-side lens and the image-side lens on the optical axis.

[0013] For the optical system according to an embodiment of the present invention, the optical system satisfies the conditional formula: 2.4 ≤ FNO ≤ 2.6, where FNO is the f-number of the optical system.

[0014] For the optical system according to an embodiment of the present invention, the optical system satisfies the conditional formula: 1 < f2 / f3 < 8, where f2 is the effective focal length of the second lens, and f3 is the effective focal length of the third lens.

[0015] For the optical system according to an embodiment of the present invention, the optical system satisfies the conditional formula: -3 < f3 / R8 < 0, where f3 is the effective focal length of the third lens, and R8 is the curvature radius of the image side surface of the third lens on the optical axis.

[0016] For the optical system according to an embodiment of the present invention, the optical system satisfies the conditional formula: TT / ImgH < 1.1, where TT is the distance from the object side surface of the first cemented lens group to the image side surface of the fifth lens on the optical axis, and ImgH is half of the diagonal length of the effective photosensitive area.

[0017] For the optical system according to an embodiment of the present invention, the optical system satisfies the conditional formula: -180 < R11 / R12 < 50, where R11 is the curvature radius of the object side surface of the fifth lens on the optical axis, and R12 is the curvature radius of the image side surface of the fifth lens on the optical axis.

[0018] For the optical system according to an embodiment of the present invention, the optical system satisfies the conditional formula: 2.0 < CT4 / |SAG41| < 30.0, where CT4 is the thickness of the fourth lens on the optical axis, and SAG 41 is the horizontal displacement from the intersection point of the object side surface of the fourth lens on the optical axis to the maximum effective radius position of the object side surface of the fourth lens.

[0019] An imaging module according to an embodiment of the second aspect of the present invention includes a photosensitive element and an optical system according to an embodiment of the first aspect of the present invention. The photosensitive element is disposed on the image side of the optical system. By adopting the above optical system, high imaging quality can be ensured, and the size of the opening on the screen during installation can be reduced, which is beneficial for packaging on electronic devices, etc., and meets the requirements of miniaturized lenses.

[0020] An electronic device according to an embodiment of the third aspect of the present invention includes a housing and an imaging module according to an embodiment of the second aspect of the present invention. The imaging module is installed in the housing. By adopting the above imaging module, high imaging quality can be ensured, and at the same time, the size of the opening on the housing can be reduced, which is beneficial for packaging.

[0021] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. Description of the Drawings

[0022] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, where:

[0023] Figure 1 is a schematic structural diagram of an optical system according to the first embodiment of the present invention;

[0024] Figure 2 are the spherical aberration curve, astigmatism curve, and distortion curve of the optical system of the first embodiment;

[0025] Figure 3Schematic structural diagram of the optical system according to the second embodiment of the present invention;

[0026] Figure 4 Spherical aberration curve, astigmatism curve and distortion curve of the optical system of the second embodiment;

[0027] Figure 5 Schematic structural diagram of the optical system according to the third embodiment of the present invention;

[0028] Figure 6 Spherical aberration curve, astigmatism curve and distortion curve of the optical system of the third embodiment;

[0029] Figure 7 Schematic structural diagram of the optical system according to the fourth embodiment of the present invention;

[0030] Figure 8 Spherical aberration curve, astigmatism curve and distortion curve of the optical system of the fourth embodiment;

[0031] Figure 9 Schematic structural diagram of the optical system according to the fifth embodiment of the present invention;

[0032] Figure 10 Spherical aberration curve, astigmatism curve and distortion curve of the optical system of the fifth embodiment;

[0033] Figure 11 Schematic structural diagram of the optical system according to the sixth embodiment of the present invention;

[0034] Figure 12 Spherical aberration curve, astigmatism curve and distortion curve of the optical system of the sixth embodiment.

[0035] Reference numerals in the drawings:

[0036] Optical system 100,

[0037] First cemented lens group L10, object side surface 2 of the first cemented lens group, image side surface 4 of the first cemented lens group, object side lens L11, image side lens L12, cemented surface 3 of the object side lens and the image side lens, second lens L20, object side surface 5 of the second lens, image side surface 6 of the second lens, third lens L30, object side surface 7 of the third lens, image side surface 8 of the third lens, fourth lens L40, object side surface 9 of the fourth lens, image side surface 10 of the fourth lens, fifth lens L50, object side surface 11 of the fifth lens, image side surface 12 of the sixth lens, infrared filter L60, object side surface 13 of the infrared filter, image side surface 14 of the infrared filter, image plane 15,

[0038] Optical axis 70, object side 80, image side 90. Detailed implementation manners

[0039] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where like or similar reference numerals denote like or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation to the present invention.

[0040] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0041] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "mounted", "connected" and "coupled" should be construed in a broad sense. For example, it may be a fixed connection, a detachable connection or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0042] Next, reference is made to Figures 1 - 12 describe an optical system 100 according to an embodiment of the present invention.

[0043] As Figures 1 - 12As shown, an optical system 100 according to an embodiment of the present invention includes a plurality of lenses. The plurality of lenses are arranged in sequence from the object side 80 (i.e., the side where light enters) to the image side 90 (i.e., the side where light exits), including a first cemented lens group L10, a second lens L20, a third lens L30, a fourth lens L40, and a fifth lens L50. Among them, the first cemented lens group includes an object-side lens L11 and an image-side lens L12 formed by cementing. The object-side lens L11 is the lens in the first cemented lens group L10 close to the object side 80, and the image-side lens L12 is the lens in the first cemented lens group L10 close to the image side 90. The third lens L30 has a negative optical power, the fourth lens L40 has a positive optical power, and at least one of the object surface and the image surface of the fourth lens L40 has an inflection point. And the object surface of the fourth lens L40 has an inflection point, or the image surface of the fourth lens L40 has an inflection point, or both the object surface and the image surface of the fourth lens L40 have inflection points. The fifth lens L50 has a negative optical power.

[0044] The optical system 100 satisfies the following conditional expressions:

[0045] 1.5 < Nds2 < 1.66, 1.5 < Nds3 < 1.66. Nds2 is the refractive index of the object-side lens L11, and Nds3 is the refractive index of the image-side lens L12.

[0046] For the optical system 100 according to an embodiment of the present invention, by setting the cemented lens group, the structure can be made compact and simple, the volume can be reduced, which is beneficial to shortening the total length of the optical system and meeting the requirements of miniaturization. At the same time, it is convenient for assembly and improves the assembly yield of the optical system; by setting an inflection point on the surface of the fourth lens L40, it is beneficial to correct the distortion generated by the optical system 100, and can reasonably control the overall aberration of the optical system to achieve good imaging quality; by reasonably configuring the optical power of the lenses, the imaging quality is further improved; by restricting the refractive indices of the object-side lens L11 and the image-side lens L12 of the first cemented lens group L10 within the above range, the optical system 100 can have excellent optical performance, achieve excellent small aberration effects, and meet the requirements of good imaging quality for high pixels.

[0047] Among them, the cemented surface of the object-side lens L11 and the image-side lens L12 can be a convex surface or a concave surface. Both the object surface and the image surface of the fourth lens L40 are aspherical surfaces, which is beneficial to correcting the spherical aberration of the optical system and improving the imaging quality of the optical system.

[0048] According to an embodiment of the present invention, the optical system 100 satisfies the conditional formula: 0.45 < CTs2 / SD11 < 1.1, where CTs2 is the thickness of the object-side lens L11 on the optical axis 70, and SD11 is the effective semi-aperture of the object side surface of the first cemented lens group. Thereby, the head aperture size of the optical system can be reduced, and at the same time, it is beneficial to the compact arrangement of the overall structure, realizing the structural characteristics of miniaturization.

[0049] According to an embodiment of the present invention, the optical system 100 satisfies the conditional formula: 6.5 < TTL / CTs3 < 13.0, where TTL is the distance from the object side surface of the first cemented lens group L10 to the imaging surface of the optical system 100 on the optical axis 70, and CTs3 is the thickness of the image-side lens L12 on the optical axis 70. Thereby, the optical system can have the characteristics of miniaturization, and at the same time, it can ensure that the first cemented lens group L10 has sufficient thickness and good molding processability, and at the same time, it can meet the characteristics of the long depth of the lens head.

[0050] According to an embodiment of the present invention, the optical system 100 satisfies the conditional formula: 0.3 < f1 / |R3| < 3.0, where f1 is the combined focal length of the first cemented lens group L10, and R3 is the radius of curvature of the cemented surface of the object-side lens L11 and the image-side lens L12 at the optical axis 70. Thereby, the light-gathering ability of the first cemented lens group L10 can be enhanced, the clarity of the optical system 100 can be improved, and the quality requirements of excellent imaging can be achieved.

[0051] According to an embodiment of the present invention, the optical system 100 satisfies the conditional formula: 2.4 ≤ FNO ≤ 2.6, where FNO is the f-number of the optical system. Thereby, while ensuring the light transmission amount, it is beneficial to meet the structural characteristics of the miniaturization of the optical system head.

[0052] According to an embodiment of the present invention, the optical system 100 satisfies the conditional formula: 1 < f2 / f3 < 8, where f2 is the effective focal length of the second lens L20, and f3 is the effective focal length of the third lens L30. By reasonably configuring the ratio of the focal lengths of the second lens L20 and the third lens L30, the field angle of the optical system 100 can be effectively expanded, which is beneficial to compressing the total length of the optical system and realizing the thin-type characteristics.

[0053] According to an embodiment of the present invention, the optical system 100 satisfies the conditional formula: -3 < f3 / R8 < 0, where f3 is the effective focal length of the third lens L30, and R8 is the radius of curvature of the image side surface of the third lens L30 at the optical axis 70. When the third lens L30 satisfies the above relationship, the aberration generated by the optical system 100 can be balanced, and at the same time, the high-order aberration generated by the second lens L20 can be further corrected, improving the imaging quality.

[0054] According to an embodiment of the present invention, the optical system 100 satisfies the conditional formula: TT / ImgH < 1.1, where TT is the distance from the object side surface of the first cemented lens group to the image side surface of the fifth lens L50 on the optical axis 70, and ImgH is half of the diagonal length of the effective photosensitive area on the photosensitive chip. Thus, high-quality imaging effects on a large image surface can be achieved, and at the same time, the total length of the optical system can be effectively reduced, thereby realizing the ultra-thin characteristics and miniaturization of the optical system.

[0055] According to an embodiment of the present invention, the optical system 100 satisfies the conditional formula: -180 < R11 / R12 < 50, where R11 is the curvature radius of the object side surface of the fifth lens L50 at the optical axis 70, and R12 is the curvature radius of the image side surface of the fifth lens L50 at the optical axis 70. That is, by reasonably defining the relationship between the curvature radii of the object side surface and the image side surface of the fifth lens L50, the optical deflection angle borne by the fifth lens L50 can be effectively distributed, and at the same time, the off-axis field astigmatism can be improved, and the imaging quality of the optical system 100 can be enhanced.

[0056] According to an embodiment of the present invention, the optical system 100 satisfies the conditional formula: 2.0 < CT4 / |SAG41| < 30.0, where CT4 is the thickness of the fourth lens L40 on the optical axis 70, and SAG 41 is the horizontal displacement from the intersection point of the object side surface of the fourth lens L40 on the optical axis 70 to the position of the maximum effective radius of the object side surface of the fourth lens L40. Here, the horizontal displacement is positive in the image side direction and negative in the object side surface direction. This makes the lens shape appropriate, which is beneficial to the manufacturing and molding of the fourth lens L40, reduces defects such as poor molding, and at the same time can correct the field aberration generated by the fourth lens L40, ensure the balance of the field of the optical system 100, and improve the imaging quality.

[0057] The optical system 100 of the present invention is described below through six specific embodiments.

[0058] Embodiment 1

[0059] As Figure 1 shown, the optical system 100 sequentially includes a first cemented lens group L10, a second lens L20, a third lens L30, a fourth lens L40, a fifth lens L50, and an infrared filter L60 from the object side (the side of the first cemented lens group L10 away from the second lens L2) to the image side (the side of the fifth lens L50 away from the fourth lens L40).

[0060] The first cemented lens group L10 is made of plastic. The first cemented lens group L10 is formed by cementing an object-side lens L11 and an image-side lens L12. The cemented surface 3 is a spherical surface. The object-side lens L11 has a positive optical power, and the image-side lens L12 has a negative optical power. Its object surface 2 is convex both near the optical axis and at the circumference. Its cemented surface 3 is convex both near the optical axis and at the circumference. Its image surface 4 is convex both near the optical axis and at the circumference.

[0061] The second lens L20 is made of plastic and has a negative optical power. Its object surface 5 is convex near the optical axis and concave at the circumference. Its image surface 6 is concave both near the optical axis and at the circumference.

[0062] The third lens L30 is made of plastic and has a negative optical power. Its object surface 7 is concave both near the optical axis and at the circumference. Its image surface 8 is concave near the optical axis and convex at the circumference.

[0063] The fourth lens L40 is made of plastic and has a positive optical power. Its object surface 9 is convex near the optical axis and concave at the circumference. Its image surface 10 is convex both near the optical axis and at the circumference.

[0064] The fifth lens L50 is made of plastic and has a negative optical power. Its object surface 11 is convex both near the optical axis and at the circumference. Its image surface 12 is concave near the optical axis and convex at the circumference.

[0065] An infrared filter L60 is disposed behind the fifth lens L50 to filter out infrared light so that the light incident on the imaging surface is visible light. The infrared filter L60 is made of glass.

[0066] The characteristics of the optical system of this embodiment are shown in Table 1.

[0067] Table 1

[0068]

[0069] Among them, EFL is the effective focal length of the optical system, FNO is the f-number of the optical system, HFOV is the maximum field of view angle of the optical system, TTL is the distance from the object surface of the first cemented lens group to the imaging surface of the optical system, and the Y radius is the radius of curvature. The reference wavelengths for the focal length, refractive index, and Abbe number are all 587.6 nm.

[0070] The high-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20 of the lens surfaces 2, 4, 5, 6, 7, 8, 9, 10, 11, 12 of this embodiment are shown in Table 2.

[0071] Table 2

[0072]

[0073] In addition, Figure 2 the spherical aberration curve of the optical system of the first embodiment is shown ( Figure 2 a), the astigmatism curve ( Figure 2 b), and the distortion curve ( Figure 2 c), where, in Figure 2 a, the spherical aberration curve shows that the light rays with wavelengths of 656.3 nm, 587.6 nm, and 486.1 nm deviate from the focal point after passing through the optical system 100; in Figure 2 b, the astigmatism curve shows the meridional image plane curvature and sagittal image plane curvature of the light rays with a wavelength of 587.6 nm after passing through the optical system 100; in Figure 2 c, the distortion curve shows the distortion at different field angles of the light rays with a wavelength of 587.6 nm after passing through the optical system 100. According to Figure 2 it can be known that the optical system 100 given in the first embodiment has a small deviation of the focal point, a good converging effect, a distortion less than 2%, and the imaging will not show an edge blurring phenomenon, and can achieve good imaging quality.

[0074] Second Embodiment

[0075] As Figure 3 and Figure 4 shown, the optical system 100 sequentially includes a first cemented lens group L10, a second lens L20, a third lens L30, a fourth lens L40, a fifth lens L50, and an infrared filter L60 from the object side (the side of the first cemented lens group L10 away from the second lens L2) to the image side (the side of the fifth lens L50 away from the fourth lens L40).

[0076] The first cemented lens group L10 is made of plastic. The first cemented lens group L10 is formed by cementing an object-side lens L11 and an image-side lens L12. The cemented surface 3 is a spherical surface. The object-side lens L11 has a positive optical power, and the image-side lens L12 has a negative optical power. Its object surface 2 is convex both near the optical axis and at the circumference. Its cemented surface 3 is convex both near the optical axis and at the circumference. Its image surface 4 is concave near the optical axis and convex at the circumference.

[0077] The second lens L20 is made of plastic and has a negative optical power. Its object surface 5 is convex near the optical axis and concave at the circumference. Its image surface 6 is concave both near the optical axis and at the circumference.

[0078] The third lens L30 is made of plastic and has a negative optical power. Its object surface 7 is concave both near the optical axis and at the circumference. Its image surface 8 is concave near the optical axis and convex at the circumference.

[0079] The fourth lens L40 is made of plastic and has a positive optical power. Its object side 9 is convex near the optical axis and concave at the circumference, and its image side 10 is convex both near the optical axis and at the circumference.

[0080] The fifth lens L50 is made of plastic and has a negative optical power. Its object side 11 is convex both near the optical axis and at the circumference, and its image side 12 is concave near the optical axis and convex at the circumference.

[0081] An infrared filter L60 is disposed behind the fifth lens L50 for filtering out infrared light so that the light incident on the imaging surface is visible light. The infrared filter L60 is made of glass.

[0082] The characteristics of the optical system of this embodiment are shown in Table 3.

[0083] Table 3

[0084]

[0085]

[0086] Among them, EFL is the effective focal length of the optical system, FNO is the f-number of the optical system, HFOV is the maximum field of view angle of the optical system, TTL is the distance from the object side of the first cemented lens group to the imaging surface of the optical system, and the Y radius is the radius of curvature. The reference wavelengths for the focal length, refractive index, and Abbe number are all 587.6 nm.

[0087] The high-order coefficient A4, A6, A8, A10, A12, A14, A16, A18, A20 of each lens surface 2, 4, 5, 6, 7, 8, 9, 10, 11, 12 of this embodiment are shown in Table 4.

[0088] Table 4

[0089]

[0090] In addition, Figure 4 shows the spherical aberration curve ( Figure 4 a), astigmatism curve ( Figure 4 b), and distortion curve ( Figure 4 c) of the optical system of the second embodiment. Among them, in Figure 4 a, the spherical aberration curve shows that the focal points of the light rays with wavelengths of 656.3 nm, 587.6 nm, and 486.1 nm deviate after passing through the optical system 100; in Figure 4 b, the astigmatism curve shows the meridional image plane bending and sagittal image plane bending of the light rays with a wavelength of 587.6 nm after passing through the optical system 100; in Figure 4In FIG. C, the distortion curve shows the distortion of light with a wavelength of 587.6 nm at different field angles after passing through the optical system 100. According to Figure 4 It can be seen that the optical system 100 given in the second embodiment has a small deviation of the focal point, a good converging effect, a distortion less than 2%, and the imaging will not show the phenomenon of blurred edges, and can achieve good imaging quality.

[0091] Embodiment 3

[0092] As Figure 5 and Figure 6 shown, the optical system 100 sequentially includes a first cemented lens group L10, a second lens L20, a third lens L30, a fourth lens L40, a fifth lens L50, and an infrared filter L60 from the object side (the side of the first cemented lens group L10 away from the second lens L2) to the image side (the side of the fifth lens L50 away from the fourth lens L40).

[0093] The first cemented lens group L10 is made of plastic. The first cemented lens group L10 is formed by cementing an object-side lens L11 and an image-side lens L12. The cemented surface 3 is a spherical surface. The object-side lens L11 has a positive optical power, and the image-side lens L12 has a positive optical power. Its object surface 2 is convex both near the optical axis and at the circumference. Its cemented surface 3 is concave both near the optical axis and at the circumference. Its image surface 4 is convex both near the optical axis and at the circumference.

[0094] The second lens L20 is made of plastic and has a negative optical power. Its object surface 5 is convex both near the optical axis and at the circumference. Its image surface 6 is concave both near the optical axis and at the circumference.

[0095] The third lens L30 is made of plastic and has a negative optical power. Its object surface 7 is concave both near the optical axis and at the circumference. Its image surface 8 is concave both near the optical axis and at the circumference.

[0096] The fourth lens L40 is made of plastic and has a positive optical power. Its object surface 9 is convex near the optical axis and concave at the circumference. Its image surface 10 is convex both near the optical axis and at the circumference.

[0097] The fifth lens L50 is made of plastic and has a negative optical power. Its object surface 11 is convex both near the optical axis and at the circumference. Its image surface 12 is concave near the optical axis and convex at the circumference.

[0098] The infrared filter L60 is arranged behind the fifth lens L50 and is used to filter out infrared light so that the light incident on the imaging surface is visible light. The infrared filter L60 is made of glass.

[0099] The characteristics of the optical system of this embodiment are shown in Table 5.

[0100] Table 5

[0101]

[0102]

[0103] Among them, EFL is the effective focal length of the optical system, FNO is the f-number of the optical system, HFOV is the maximum field of view angle of the optical system, TTL is the distance from the object side surface of the first cemented lens group to the imaging surface of the optical system, and the Y radius is the radius of curvature. The reference wavelengths for the focal length, refractive index, and Abbe number are all 587.6 nm.

[0104] The higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20 of the lens surfaces 2, 4, 5, 6, 7, 8, 9, 10, 11, 12 of this embodiment are shown in Table 6.

[0105] Table 6

[0106]

[0107] In addition, Figure 6 shows the spherical aberration curve ( Figure 6 a), astigmatism curve ( Figure 6 b), and distortion curve ( Figure 6 c) of the optical system of the third embodiment. Among them, in Figure 6 a, the spherical aberration curve shows that the focal points of the light rays with wavelengths of 656.3 nm, 587.6 nm, and 486.1 nm deviate after passing through the optical system 100; in Figure 6 b, the astigmatism curve shows the meridional image plane bending and sagittal image plane bending of the light rays with a wavelength of 587.6 nm after passing through the optical system 100; in Figure 6 c, the distortion curve shows the distortion at different field of view angles of the light rays with a wavelength of 587.6 nm after passing through the optical system 100. According to Figure 6 it can be known that the optical system 100 given in the third embodiment has a small focal point deviation, a good converging effect, a distortion less than 2%, and the imaging does not show edge blurring, and can achieve good imaging quality.

[0108] Embodiment Four

[0109] As Figure 7 and Figure 8 shown, the optical system 100 sequentially includes a first cemented lens group L10, a second lens L20, a third lens L30, a fourth lens L40, a fifth lens L50, and an infrared filter L60 from the object side (the side of the first cemented lens group L10 away from the second lens L2) to the image side (the side of the fifth lens L50 away from the fourth lens L40).

[0110] The first cemented lens group L10 is made of plastic. The first cemented lens group L10 is formed by cementing an object-side lens L11 and an image-side lens L12. The cemented surface 3 is a spherical surface. The object-side lens L11 has a positive optical power, and the image-side lens L12 has a negative optical power. Its object surface 2 is convex both near the optical axis and at the circumference. Its cemented surface 3 is concave both near the optical axis and at the circumference. Its image surface 4 is convex both near the optical axis and at the circumference.

[0111] The second lens L20 is made of plastic and has a negative optical power. Its object surface 5 is convex near the optical axis and concave at the circumference. Its image surface 6 is concave both near the optical axis and at the circumference.

[0112] The third lens L30 is made of plastic and has a negative optical power. Its object surface 7 is concave both near the optical axis and at the circumference. Its image surface 8 is concave near the optical axis and convex at the circumference.

[0113] The fourth lens L40 is made of plastic and has a positive optical power. Its object surface 9 is convex near the optical axis and concave at the circumference. Its image surface 10 is convex both near the optical axis and at the circumference.

[0114] The fifth lens L50 is made of plastic and has a negative optical power. Its object surface 11 is convex both near the optical axis and at the circumference. Its image surface 12 is concave near the optical axis and convex at the circumference.

[0115] An infrared filter L60 is arranged behind the fifth lens L50 to filter out infrared light so that the light incident on the imaging surface is visible light. The infrared filter L60 is made of glass.

[0116] The characteristics of the optical system of this embodiment are shown in Table 7.

[0117] Table 7

[0118]

[0119]

[0120] Among them, EFL is the effective focal length of the optical system, FNO is the f-number of the optical system, HFOV is the maximum field of view angle of the optical system, TTL is the distance from the object surface of the first cemented lens group to the imaging surface of the optical system, and the Y radius is the radius of curvature. The reference wavelengths for the focal length, refractive index, and Abbe number are all 587.6 nm.

[0121] The high-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20 of the lens surfaces 2, 4, 5, 6, 7, 8, 9, 10, 11, 12 of this embodiment are shown in Table 8.

[0122] Table 8

[0123]

[0124]

[0125] In addition, Figure 8 the spherical aberration curve of the optical system of the fourth embodiment is shown ( Figure 8 a), the astigmatism curve ( Figure 8 b), and the distortion curve ( Figure 8 c), where, in Figure 8 a, the spherical aberration curve shows that the light rays with wavelengths of 656.3 nm, 587.6 nm, and 486.1 nm deviate from the focal point after passing through the optical system 100; in Figure 8 b, the astigmatism curve shows the meridional image plane curvature and the sagittal image plane curvature of the light rays with a wavelength of 587.6 nm after passing through the optical system 100; in Figure 8 c, the distortion curve shows the distortion at different field angles of the light rays with a wavelength of 587.6 nm after passing through the optical system 100. According to Figure 8 it can be known that the optical system 100 given in the fourth embodiment has a small deviation of the focal point, a good converging effect, a distortion less than 2%, and the imaging will not show edge blurring, and can achieve good imaging quality.

[0126] Embodiment Five

[0127] As Figure 9 and Figure 10 shown, the optical system 100 sequentially includes a first cemented lens group L10, a second lens L20, a third lens L30, a fourth lens L40, a fifth lens L50, and an infrared filter L60 from the object side (the side of the first cemented lens group L10 away from the second lens L2) to the image side (the side of the fifth lens L50 away from the fourth lens L40).

[0128] The first cemented lens group L10 is made of plastic. The first cemented lens group L10 is formed by cementing an object-side lens L11 and an image-side lens L12. The cemented surface 3 is a spherical surface. The object-side lens L11 has a positive optical power, and the image-side lens L12 has a negative optical power. Its object surface 2 is convex both near the optical axis and at the circumference. Its cemented surface 3 is convex both near the optical axis and at the circumference. Its image surface 4 is concave near the optical axis and convex at the circumference.

[0129] The second lens L20 is made of plastic and has a negative optical power. Its object surface 5 is concave both near the optical axis and at the circumference. Its image surface 6 is convex near the optical axis and concave at the circumference.

[0130] The third lens L30 is made of plastic and has a negative optical power. Its object side 7 is convex near the optical axis and concave at the circumference. Its image side 8 is concave near the optical axis and convex at the circumference.

[0131] The fourth lens L40 is made of plastic and has a positive optical power. Its object side 9 is convex near the optical axis and concave at the circumference. Its image side 10 is convex both near the optical axis and at the circumference.

[0132] The fifth lens L50 is made of plastic and has a negative optical power. Its object side 11 is concave near the optical axis and convex at the circumference. Its image side 12 is concave near the optical axis and convex at the circumference.

[0133] The infrared filter L60 is disposed behind the fifth lens L50 and is used to filter out infrared light so that the light incident on the imaging surface is visible light. The infrared filter L60 is made of glass.

[0134] The characteristics of the optical system of this embodiment are shown in Table 9.

[0135] Table 9

[0136]

[0137] Among them, EFL is the effective focal length of the optical system, FNO is the f-number of the optical system, HFOV is the maximum field of view angle of the optical system, TTL is the distance from the object side of the first cemented lens group to the imaging surface of the optical system, and the Y radius is the radius of curvature. The reference wavelengths for the focal length, refractive index, and Abbe number are all 587.6 nm.

[0138] The high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20 of the lens surfaces 2, 4, 5, 6, 7, 8, 9, 10, 11, 12 of this embodiment are shown in Table 10.

[0139] Table 10

[0140]

[0141]

[0142] In addition, Figure 10 shows the spherical aberration curve ( Figure 10 a), astigmatism curve ( Figure 10 b), and distortion curve ( Figure 10 c) of the optical system of the fifth embodiment. Among them, in Figure 10 a, the spherical aberration curve shows that the light rays with wavelengths of 656.3 nm, 587.6 nm, and 486.1 nm deviate from the focal point after passing through the optical system 100; in Figure 10In Fig. b, the astigmatism curve shows the meridional image plane curvature and sagittal image plane curvature of the light with a wavelength of 587.6 nm after passing through the optical system 100; in Figure 10 In Fig. c, the distortion curve shows the distortion at different field angles of the light with a wavelength of 587.6 nm after passing through the optical system 100. According to Figure 10 it can be known that the optical system 100 given in the fifth embodiment has a small deviation of the focal point, good converging effect, distortion less than 2%, and the imaging will not show edge blurring phenomenon, and can achieve good imaging quality.

[0143] Embodiment Six

[0144] As Figure 11 and Figure 12 shown, the optical system 100 successively includes a first cemented lens group L10, a second lens L20, a third lens L30, a fourth lens L40, a fifth lens L50, and an infrared filter L60 from the object side (the side of the first cemented lens group L10 far from the second lens L2) to the image side (the side of the fifth lens L50 far from the fourth lens L40).

[0145] The first cemented lens group L10 is made of plastic. The first cemented lens group L10 is formed by cementing an object-side lens L11 and an image-side lens L12. The cemented surface 3 is a spherical surface. The object-side lens L11 has a positive optical power, and the image-side lens L12 has a negative optical power. Its object surface 2 is convex both near the optical axis and at the circumference. Its cemented surface 3 is concave both near the optical axis and at the circumference. Its image surface 4 is concave near the optical axis and convex at the circumference.

[0146] The second lens L20 is made of plastic and has a negative optical power. Its object surface 5 is convex both near the optical axis and at the circumference. Its image surface 6 is concave both near the optical axis and at the circumference.

[0147] The third lens L30 is made of plastic and has a negative optical power. Its object surface 7 is convex near the optical axis and concave at the circumference. Its image surface 8 is concave near the optical axis and convex at the circumference.

[0148] The fourth lens L40 is made of plastic and has a positive optical power. Its object surface 9 is convex near the optical axis and concave at the circumference. Its image surface 10 is convex both near the optical axis and at the circumference.

[0149] The fifth lens L50 is made of plastic and has a negative optical power. Its object surface 11 is concave near the optical axis and convex at the circumference. Its image surface 12 is concave near the optical axis and convex at the circumference.

[0150] The infrared filter L60 is arranged behind the fifth lens L50 and is used to filter out infrared light so that the light incident on the imaging surface is visible light. The infrared filter L60 is made of glass.

[0151] The characteristics of the optical system of this embodiment are shown in Table 11.

[0152] Table 11

[0153]

[0154] Among them, EFL is the effective focal length of the optical system, FNO is the f-number of the optical system, HFOV is the maximum field of view angle of the optical system, TTL is the distance from the object side of the first cemented lens group to the imaging plane of the optical system, the Y radius is the radius of curvature, and the reference wavelengths of the focal length, refractive index, and Abbe number are all 587.6 nm.

[0155] The high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 of the lens surfaces 2, 4, 5, 6, 7, 8, 9, 10, 11, and 12 of this embodiment are shown in Table 12.

[0156] Table 12

[0157]

[0158]

[0159] In addition, Figure 12 shows the spherical aberration curve ( Figure 12 a), astigmatism curve ( Figure 12 b), and distortion curve ( Figure 12 c) of the optical system of the sixth embodiment. Among them, in Figure 12 a, the spherical aberration curve shows that the light rays with wavelengths of 656.3 nm, 587.6 nm, and 486.1 nm deviate from the focal point after passing through the optical system 100; in Figure 12 b, the astigmatism curve shows the meridional image plane bending and sagittal image plane bending of the light rays with a wavelength of 587.6 nm after passing through the optical system 100; in Figure 12 c, the distortion curve shows the distortion at different field of view angles of the light rays with a wavelength of 587.6 nm after passing through the optical system 100. According to Figure 12 it can be known that the optical system 100 given in the sixth embodiment has a small deviation of the focal point, a good converging effect, a distortion less than 2%, and the imaging does not show an edge blurring phenomenon, and can achieve good imaging quality.

[0160] The parameter relationships of the optical systems according to the six embodiments of the present invention are shown in the following Tables 13 - 22.

[0161] Table 13

[0162] 1.50 < Nds2 < 1.66, 1.50 < Nds3 < 1.66 Example 1 1.535,1.577 Example 2 1.535,1.596 Example 3 1.558,1.544 Example 4 1.627,1.544 Example 5 1.544,1.626 Example 6 1.635,1.544

[0163] As can be seen from Table 13, the six embodiments according to the present invention all satisfy the conditional expressions: 1.5 < Nds2 < 1.66, 1.5 < Nds3 < 1.66.

[0164] Table 14

[0165]

[0166]

[0167] As can be seen from Table 14, the six embodiments according to the present invention all satisfy the conditional expression: 0.45 < CTs2 / SD11 < 1.1.

[0168] Table 15

[0169] 6.5 < TTL / CTs3 < 13.0 Example 1 4.37 / 0.43 10.16 Example 2 4.39 / 0.367 11.96 Example 3 4.4 / 0.558 7.89 Example 4 4.358 / 0.579 7.53 Example 5 4.481 / 0.253 17.71 Example 6 4.58 / 0.655 6.99

[0170] As can be seen from Table 15, the six embodiments according to the present invention all satisfy the conditional expression: 6.5 < TTL / CTs3 < 13.0.

[0171] Table 16

[0172] 0.3 < f1 / |R3| < 3.0 Example 1 3.48 / |-3.329| 1.045 Example 2 3.53 / |-3.08| 1.146 Example 3 2.95 / |1.238| 2.383 Example 4 3.01 / |1.517| 1.984 Example 5 3.40 / |-6.179| 0.550 Example 6 3.87 / |1.41| 2.745

[0173] As can be seen from Table 16, the six embodiments according to the present invention all satisfy the conditional expression: 0.3 < f1 / |R3| < 3.0.

[0174] Table 17

[0175] 2.4 ≤ FNO ≤ 2.6 Example 1 2.5 Example 2 2.5 Example 3 2.6 Example 4 2.5 Example 5 2.52 Example 6 2.55

[0176] As can be seen from Table 17, the six embodiments according to the present invention all satisfy the conditional expression: 2.4 ≤ FNO ≤ 2.6.

[0177] Table 18

[0178]

[0179]

[0180] As can be seen from Table 18, the six embodiments according to the present invention all satisfy the conditional expression: 1 < f2 / f3 < 8.

[0181] Table 19

[0182] -3 < f3 / R8 < 0 Example 1 -3.68 / 6.408 -0.574 Example 2 -3.6 / 6.44 -0.559 Example 3 -4.03 / 2.879 -1.4 Example 4 -6.07 / 6.61 -0.92 Example 5 -6.75 / 4.158 -1.623 Example 6 -11.46 / 7.095 -1.615

[0183] As can be seen from Table 19, the six embodiments according to the present invention all satisfy the conditional expression: -3 < f3 / R8 < 0.

[0184] Table 20

[0185] TT / ImgH < 1.1 Example 1 3.335 / 3.08 1.083 Example 2 3.351 / 3.08 1.088 Example 3 3.362 / 3.08 1.092 Example 4 3.364 / 3.08 1.09 Example 5 3.592 / 3.3 1.088 Example 6 3.657 / 3.35 1.092

[0186] As can be seen from Table 20, the six embodiments according to the present invention all satisfy the conditional expression: TT / ImgH < 1.1.

[0187] Table 21

[0188] -180 < R11 / R12 < 50 Example 1 3.23 / 0.799 4.04 Example 2 3.121 / 0.803 3.89 Example 3 26.301 / 0.833 31.57 Example 4 31.371 / 0.824 38.07 Example 5 -232.222 / 1.527 -152.08 Example 6 -32.62 / 1.522 -21.43

[0189] As can be seen from Table 21, the six embodiments according to the present invention all satisfy the conditional expression: -180 < R11 / R12 < 50.

[0190] Table 22

[0191] 2.0 < CT4 / |SAG41| < 30.0 Example 1 0.636 / |-0.034| 18.7 Example 2 0.647 / |-0.023| 28.13 Example 3 0.815 / |-0.138| 5.906 Example 4 0.63 / |-0.203| 3.103 Example 5 0.647 / |-0.130| 4.977 Example 6 0.652 / |-0.186| 3.505

[0192] As can be seen from Table 22, the six embodiments according to the present invention all satisfy the conditional expression: 2.0 < CT4 / |SAG41| < 30.0.

[0193] The imaging module according to an embodiment of the present invention includes a photosensitive element and an optical system 100 according to an embodiment of the present invention. The photosensitive element is disposed on the image side of the optical system 100. By adopting the above optical system 100, high imaging quality can be guaranteed, and the size of the opening on the electronic device screen during the installation of the imaging module can also be reduced, which is beneficial to the packaging on the electronic device and meets the miniaturization requirements.

[0194] The electronic device according to an embodiment of the present invention includes a housing and an imaging module according to an embodiment of the present invention. The imaging module is installed on the housing. Here, the electronic device can be a mobile phone, a tablet computer, etc. By adopting the above imaging module, high imaging quality can be guaranteed, and at the same time, the size of the opening on the housing can be reduced, which is beneficial to the packaging.

[0195] The other configurations and operations of the electronic device according to an embodiment of the present invention are known to those of ordinary skill in the art and will not be described in detail here.

[0196] In the description of the present invention, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include direct contact between the first and second features, or may include non-direct contact between the first and second features but through additional features therebetween. Moreover, the first feature being "above", "over" and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature.

[0197] In the description of this specification, the descriptions with reference to the terms "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0198] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. An optical system, characterized in that, There are a total of six lenses with optical power, including a first cemented lens group, a second lens, a third lens, a fourth lens, and a fifth lens arranged in sequence from the object side to the image side. Among them, the first cemented lens group only has an object-side lens and an image-side lens formed by cementing. The object-side lens is the lens in the first cemented lens group close to the object side, the object surface of the object-side lens is convex near the optical axis, the image-side lens is the lens in the first cemented lens group close to the image side, the third lens has a negative optical power, the image surface of the third lens is concave near the optical axis, the fourth lens has a positive optical power, the object surface and the image surface of the fourth lens are convex near the optical axis, and at least one of the object surface and the image surface of the fourth lens has an inflection point. The fifth lens has a negative optical power, and the image surface of the fifth lens is concave near the optical axis; The optical system satisfies the following conditional expressions: 1.5 < Nds2 < 1.66, 1.5 < Nds3 < 1.66, Nds2 is the refractive index of the object-side lens of the first cemented lens group, and Nds3 is the refractive index of the image-side lens of the first cemented lens group; The optical system satisfies the conditional expression: 6.5 < TTL / CTs3 < 13.0, TTL is the distance from the object surface of the first cemented lens group to the imaging surface of the optical lens on the optical axis, and CTs3 is the thickness of the image-side lens on the optical axis; The optical system satisfies the conditional expression: 0.3 < f1 / |R3| < 3.0, f1 is the combined focal length of the first cemented lens group, and R3 is the curvature radius of the cemented surface of the object-side lens and the image-side lens on the optical axis.

2. The optical system according to claim 1, wherein, The optical system satisfies the conditional expression: 0.45 < CTs2 / SD11 < 1.1, CTs2 is the thickness of the object-side lens on the optical axis, and SD11 is the effective semi-aperture of the object surface of the first cemented lens group.

3. The optical system according to claim 1, wherein The optical system satisfies the conditional expression: 2.4 ≤ FNO ≤ 2.6, FNO is the f-number of the optical system.

4. The optical system according to claim 1, wherein The optical system satisfies the conditional expression: 1 < f2 / f3 < 8, f2 is the effective focal length of the second lens, and f3 is the effective focal length of the third lens.

5. The optical system according to claim 1, characterized in that The optical system satisfies the conditional expression: -3 < f3 / R8 < 0, f3 is the effective focal length of the third lens, and R8 is the curvature radius of the image surface of the third lens on the optical axis.

6. The optical system according to claim 1, characterized in that, The optical system satisfies the conditional expression: TT / ImgH < 1.1, TT is the distance from the object surface of the first cemented lens group to the image surface of the fifth lens on the optical axis, and ImgH is half of the diagonal length of the effective photosensitive area.

7. The optical system according to claim 1, wherein The optical system satisfies the conditional expression: -180 < R11 / R12 < 50, R11 is the curvature radius of the object surface of the fifth lens on the optical axis, and R12 is the curvature radius of the image surface of the fifth lens on the optical axis.

8. The optical system according to claim 1, wherein The optical system satisfies the conditional expression: 2.0 < CT4 / |SAG41| < 30.0, CT4 is the thickness of the fourth lens on the optical axis, and SAG 41 is the horizontal displacement from the intersection of the object side surface of the fourth lens on the optical axis to the position of the maximum effective radius of the object side surface of the fourth lens.

9. An imaging module, characterized in that, It includes a photosensitive element and the optical system according to any one of claims 1-8, and the photosensitive element is arranged on the image side of the optical system.

10. An electronic device, characterized in that, It includes a housing and the imaging module according to claim 9, and the imaging module is installed in the housing.

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