Optical lens, optical fingerprint module and electronic device

Abstract

The present invention provides an optical lens, an optical fingerprint module, and an electronic device. The optical lens includes: a first lens having a negative refractive power; a second lens having a positive refractive power; and a third lens having a positive refractive power. The first lens to the third lens are sequentially arranged along the direction from the object side of the optical lens to the imaging surface of the optical lens, 3.5 < TTL / f < 6, and TTL < 1.95 mm, where TTL is the distance on the optical axis from the intersection of the object-side surface of the first lens and the optical axis of the optical lens to the imaging surface, and f is the total focal length of the optical lens. The optical fingerprint module includes an image sensor and an optical lens, and the image sensor is disposed on the image side of the optical lens. The electronic device includes a display screen and an optical fingerprint module, and the display screen is disposed on the object side of the optical lens. According to the optical lens, the optical fingerprint module, and the electronic device of the present invention, miniaturization of the optical lens can be achieved while ensuring imaging performance.

Description

Technical Field

[0001] The present application relates to the field of optics, and in particular, to an optical lens, an optical fingerprint module, and an electronic device. Background Art

[0002] With the development of full-screen displays, fingerprint recognition has become a basic configuration for mobile phone displays. Currently, the three fingerprint recognition technologies existing in the market are capacitive, ultrasonic, and optical. Among them, the optical type can meet the requirements of full-screen displays, has good anti-interference ability, recognition ability, and reasonable cost control, making it have a strong development prospect. However, the current optical lenses in the market are relatively large in size. Limited by factors such as the number of lenses and processing dimensions, they cannot meet the pursuit of miniaturization of fingerprint lenses inside mobile phones, resulting in the volume of fingerprint lenses and sensor sizes currently circulating in the market still being too large and occupying space. In order to better match the internal space of mobile phones, there is an urgent need for a miniaturized optical lens to meet the requirements of the mobile phone market for optical fingerprint lenses.

[0003] The above information disclosed in this background art section is only used to enhance the understanding of the background of the present disclosure. Therefore, the above information may include information that neither forms any part of the prior art nor forms information of the prior art that may be taught to those of ordinary skill in the art. Summary of the Invention

[0004] The present invention content is provided to introduce selected concepts that will be further described in the following detailed description in a simplified form. The present invention content is neither intended to identify the key features or essential features of the claimed subject matter, nor is it intended to be used to help determine the scope of the claimed subject matter.

[0005] In order to solve the problem that the volume of fingerprint lenses currently circulating in the market is too large and occupies space, the present invention provides an optical lens, an optical fingerprint module, and an electronic device, which can achieve miniaturization while ensuring imaging performance.

[0006] A first aspect of the present invention provides an optical lens, wherein the optical lens includes: a first lens having a negative refractive power; a second lens having a positive refractive power; and a third lens having a positive refractive power, wherein the first lens to the third lens are sequentially arranged along the direction from the object side of the optical lens to the imaging surface of the optical lens, wherein 3.5 < TTL / f < 6, and TTL < 1.95 mm, TTL is the distance on the optical axis from the intersection of the object-side surface of the first lens and the optical axis of the optical lens to the imaging surface, and f is the total focal length of the optical lens.

[0007] In the first aspect, the object-side surface of the first lens is concave along the optical axis.

[0008] In the first aspect, the object surface of the second lens is convex along the optical axis.

[0009] In the first aspect, the object surface of the third lens is convex along the optical axis, and the image surface of the third lens is concave along the optical axis.

[0010] In the first aspect, 120° < fov < 140°, where fov is the field of view angle of the optical lens.

[0011] In the first aspect, 1.8 < ImgH / f < 2.5, where ImgH is half of the diagonal length of the effective imaging area of the imaging surface of the optical lens.

[0012] In the first aspect, 7 < TTL / CT1 < 9, where CT1 is the thickness of the central part of the first lens on the optical axis.

[0013] In the first aspect, 1.7 < (CT2 + CT3) / f < 2, where CT2 is the thickness of the central part of the second lens on the optical axis, and CT3 is the thickness of the central part of the third lens on the optical axis.

[0014] In the first aspect, 0.9 < BFL / f < 1.6, where BFL is the distance from the intersection of the image surface of the third lens and the optical axis to the imaging surface.

[0015] In the first aspect, 2.8 < |f1| / f < 4.2, where f1 is the focal length of the first lens.

[0016] In the first aspect, 4.5 < |f2 + f3| / f < 6.5, where f2 is the focal length of the second lens and f3 is the focal length of the third lens.

[0017] In the first aspect, 1.5 < ND1 < 1.7, 1.5 < ND2 < 1.7, 1.5 < ND3 < 1.7, where ND1, ND2, and ND3 are the refractive indices of the first lens, the second lens, and the third lens, respectively.

[0018] In the first aspect, 50 < VD1 < 70, 50 < VD2 < 70, 20 < VD3 < 50, where VD1, VD2, and VD3 are the Abbe numbers of the first lens, the second lens, and the third lens, respectively.

[0019] In the first aspect, 0.2 < |R11 / R12| < 0.4, where R11 is the radius of curvature of the object surface of the first lens and R12 is the radius of curvature of the image surface of the first lens.

[0020] In a first aspect, 0.05 < |R31 / R32| < 0.25, where R31 is the radius of curvature of the object-side surface of the third lens, and R32 is the radius of curvature of the image-side surface of the third lens.

[0021] In a first aspect, SD11 is the effective radius of the object-side surface of the first lens, and SD21 is the effective radius of the object-side surface of the second lens.

[0022] In a first aspect, the constant F-number of the optical lens satisfies: 1.3 < F-number < 1.6.

[0023] A second aspect of the present invention provides an optical lens. The optical lens includes: a plurality of lenses arranged in sequence along the direction from the object side of the optical lens to the imaging surface of the optical lens, where 3.5 < TTL / f < 6, and TTL < 1.95 mm. TTL is the distance on the optical axis from the intersection of the object-side surface of the lens closest to the object side of the plurality of lenses and the optical axis of the optical lens to the imaging surface, and f is the total focal length of the optical lens.

[0024] A third aspect of the present invention provides an optical fingerprint module, where the optical fingerprint module includes an image sensor and the optical lens as described above, and the image sensor is disposed on the image side of the optical lens.

[0025] A fourth aspect of the present invention provides an electronic device, where the electronic device includes a display screen and the optical fingerprint module as described above, and the display screen is disposed on the object side of the optical lens.

[0026] According to the optical lens, optical fingerprint module, and electronic device of the present invention, by using 3.5 < TTL / f < 6 and TTL < 1.95 mm, miniaturization of the optical lens can be achieved while ensuring imaging performance.

[0027] To make the above objects, features, and advantages of the present application more obvious and understandable, the following specifically enumerates preferred embodiments and, in conjunction with the accompanying drawings, provides a detailed description as follows. Description of the Drawings

[0028] To more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required in the embodiments. It should be understood that the following drawings only show some embodiments of the present application and should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0029] Figure 1 It is a diagram showing a first example of an electronic device having an optical lens.

[0030] Figure 2 Present Figure 1 the astigmatism curve of the optical lens shown.

[0031] Figure 3 Present Figure 1 the distortion curve of the optical lens shown.

[0032] Figure 4 Present Figure 1 the MTF curve of the optical lens shown.

[0033] Figure 5 is a diagram showing a second example of an electronic device having an optical lens.

[0034] Figure 6 Present Figure 5 the astigmatism curve of the optical lens shown.

[0035] Figure 7 Present Figure 5 the distortion curve of the optical lens shown.

[0036] Figure 8 Present Figure 5 the MTF curve of the optical lens shown.

[0037] Figure 9 is a diagram showing a third example of an electronic device having an optical lens.

[0038] Figure 10 Present Figure 9 the astigmatism curve of the optical lens shown.

[0039] Figure 11 Present Figure 9 the distortion curve of the optical lens shown.

[0040] Figure 12 Present Figure 9 the MTF curve of the optical lens shown.

[0041] Icons: 100 - display screen; 110 - first lens; 120 - second lens; 130 - third lens; 140 - filter; 150 - image sensor; 210 - first lens; 220 - second lens; 230 - third lens; 240 - filter; 250 - image sensor; 310 - first lens; 320 - second lens; 330 - third lens; 340 - filter; 350 - image sensor; STO - diaphragm. Detailed Description of the Invention

[0042] The following specific embodiments are provided to assist the reader in obtaining a comprehensive understanding of the methods, devices, and / or systems described herein. However, after understanding the disclosure of the present application, various transformations, modifications, and equivalents of the methods, devices, and / or systems described herein will be apparent. For example, the order of operations described herein is merely illustrative and is not limited to the order set forth herein. Rather, changes that will be apparent after understanding the disclosure of the present application may be made, except for operations that must occur in a specific order. In addition, descriptions of features known in the art may be omitted for the sake of clarity and conciseness.

[0043] The features described herein may be implemented in different forms and are not to be construed as limited to the examples described herein. Rather, the examples described herein have been provided only to illustrate some of the many possible ways of implementing the methods, devices, and / or systems described herein that will be apparent after understanding the disclosure of the present application.

[0044] The first aspect of the present disclosure provides an optical lens that can be miniaturized while ensuring imaging performance.

[0045] In an embodiment of the present application, the first lens is the lens closest to the object (or subject), and the third lens is the lens closest to the imaging surface (or image sensor). In addition, in the present application, the curvature radius, effective radius, and thickness of the lens, the distance from the object surface of the first lens to the imaging surface (TTL), half of the diagonal length of the effective imaging area of the imaging surface (1 / 2)(ImgH), and the focal length are all expressed in millimeters (mm).

[0046] In addition, the thickness of the lens, the distance between the lenses, and the TTL are distances measured based on the optical axis of the lens. In addition, in the description of the shape of the lens, the expression that one surface of the lens bulges along the optical axis means that the paraxial region of the corresponding surface bulges, and the expression that one surface of the lens is recessed along the optical axis means that the paraxial region of the corresponding surface is recessed. Therefore, even when one surface of the lens is described as bulging, the edge portion of the said one surface of the lens may be recessed. Similarly, even when one surface of the lens is described as recessed, the edge portion of the said one surface of the lens may bulge.

[0047] The optical lens includes three lenses. For example, the optical lens includes a first lens, a second lens, and a third lens sequentially arranged from the object side of the optical lens.

[0048] The first lens has a refractive power. For example, the first lens has a negative refractive power. One surface of the first lens may be recessed. For example, the object surface of the first lens is recessed along the optical axis.

[0049] The first lens may have an aspherical surface. For example, both surfaces of the first lens are aspherical. The first lens may be formed of a material having a high light transmittance and excellent processability. For example, the first lens is formed of plastic. The refractive index of the first lens is greater than 1.5 and less than 1.7.

[0050] The second lens has a refractive power. For example, the second lens has a positive refractive power. One surface of the second lens may be convex. For example, the object-side surface of the second lens is convex along the optical axis.

[0051] The second lens may have an aspherical surface. For example, both surfaces of the second lens are aspherical. The second lens may be formed of a material having a high light transmittance and excellent processability. For example, the second lens is formed of plastic. The refractive index of the second lens is greater than 1.5 and less than 1.7.

[0052] The third lens has a refractive power. For example, the third lens has a positive refractive power. One surface of the third lens may be convex. For example, the object-side surface of the third lens is convex along the optical axis, and the image-side surface of the third lens is concave along the optical axis.

[0053] The third lens may have an aspherical surface. For example, both surfaces of the third lens are aspherical. The third lens may be formed of a material having a high light transmittance and excellent processability. For example, the third lens is formed of plastic. The refractive index of the third lens is greater than 1.5 and less than 1.7.

[0054] Any aspherical surface of the first lens to the third lens may be expressed by Equation 1:

[0055]

[0056] where R is the radius of curvature, K is the conic coefficient, A1 - A20 are the high-order term coefficients of the aspherical surface, X is the effective radius value of the corresponding surface of the lens, and Z is the sag of the aspherical surface.

[0057] The optical lens may have a positive refractive power. That is, the combined focal length of the optical lens including the first lens, the second lens, and the third lens has a positive value. In some embodiments, the optical lens may further include a filter and / or a diaphragm.

[0058] The filter may be disposed on the image-side of the third lens, and the filter may be disposed between the third lens and an image sensor described below. The filter blocks light of some wavelengths so that a clear image can be achieved. For example, the filter is an infrared filter for blocking infrared-wavelength light.

[0059] The diaphragm is arranged to control the amount of light incident on the lens. According to different embodiments, the diaphragm may be arranged between two adjacent lenses. For example, the diaphragm may be arranged between the first lens and the second lens.

[0060] The second aspect of the present disclosure further relates to an optical fingerprint module. The optical fingerprint module includes the optical lens and the image sensor described in the foregoing first aspect, and the image sensor is disposed on the image side of the optical lens. The image sensor can form an imaging surface. For example, the surface of the photosensitive pixel array of the image sensor can form an imaging surface.

[0061] The third aspect of the present disclosure further relates to an electronic device. The electronic device includes a display screen and the optical fingerprint module as described above, and the display screen is disposed on the object side of the optical lens. Here, the electronic device can be a portable or mobile terminal such as a mobile phone, a tablet computer, a game device, etc. In the electronic device, the optical fingerprint module is disposed under the display screen for receiving a light beam carrying fingerprint information. The optical lens in the optical fingerprint module is used to guide the incident light beam to the image sensor, and the image sensor converts the light beam into a fingerprint signal and obtains a fingerprint image based on the fingerprint signal. In an embodiment, the display screen can provide a light source for the finger, and the light source illuminates the finger and reflects the light beam carrying the optical signal.

[0062] In the optical lens, the optical fingerprint module, and the electronic device involved in the present disclosure, the following conditional expressions can be satisfied:

[0063] In some embodiments, 3.5 < TTL / f < 6 is satisfied.

[0064] In some embodiments, TTL < 1.95 mm is satisfied.

[0065] In some embodiments, 120° < fov < 140° is satisfied.

[0066] In some embodiments, 1.8 < ImgH / f < 2.5 is satisfied.

[0067] In some embodiments, 7 < TTL / CT1 < 9 is satisfied.

[0068] In some embodiments, 1.7 < (CT2 + CT3) / f < 2 is satisfied.

[0069] In some embodiments, 0.9 < BFL / f < 1.6 is satisfied.

[0070] In some embodiments, 2.8 < |f1| / f < 4.2 is satisfied.

[0071] In some embodiments, 4.5 < |f2 + f3| / f < 6.5 is satisfied.

[0072] In some embodiments, 1.5 < ND1 < 1.7 is satisfied.

[0073] In some embodiments, 1.5 < ND2 < 1.7 is satisfied.

[0074] In some embodiments, 1.5 < ND3 < 1.7 is satisfied.

[0075] In some embodiments, 50 < VD1 < 70 is satisfied.

[0076] In some embodiments, 50 < VD2 < 70 is satisfied.

[0077] In some embodiments, 20 < VD3 < 50 is satisfied.

[0078] In some embodiments, 0.2 < |R11 / R12| < 0.4 is satisfied.

[0079] In some embodiments, 0.05 < |R31 / R32| < 0.25 is satisfied.

[0080] In some embodiments, 1.8 < |SD11 / SD21| < 4 is satisfied.

[0081] In some embodiments, 1.3 < F-number < 1.6 is satisfied.

[0082] In the above expressions, TTL is the distance on the optical axis from the intersection of the object-side surface of the first lens and the optical axis to the imaging surface, f is the total focal length of the optical lens, fov is the field of view angle of the optical lens, ImgH is half of the diagonal length of the effective imaging area of the imaging surface of the optical lens. Here, the effective imaging area is the area of the photosensitive pixels of the sensor, CT1 is the thickness on the optical axis of the central part of the first lens, CT2 is the thickness on the optical axis of the central part of the second lens, CT3 is the thickness on the optical axis of the central part of the third lens, BFL is the distance from the intersection of the image-side surface of the third lens and the optical axis to the imaging surface, f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, ND1, ND2, and ND3 are the refractive indices of the first lens, the second lens, and the third lens respectively, VD1, VD2, and VD3 are the Abbe numbers of the first lens, the second lens, and the third lens respectively, R11 is the curvature radius of the object-side surface of the first lens, R12 is the curvature radius of the image-side surface of the first lens, R31 is the curvature radius of the object-side surface of the third lens, R32 is the curvature radius of the image-side surface of the third lens, SD11 is the effective radius of the object-side surface of the first lens, SD21 is the effective radius of the object-side surface of the second lens, and the F-number is a constant representing the brightness of the optical lens.

[0083] Here, according to 3.5 < TTL / f < 6 and TTL < 1.95 mm, miniaturization of the optical lens can be achieved while ensuring imaging performance. In addition, according to 120° < fov < 140°, an ultra-wide angle of the optical lens can be achieved. In addition, according to 1.8 < |SD11 / SD21| < 4, an ultra-wide angle of the optical lens can be further achieved.

[0084] Next, electronic devices according to several examples will be described.

[0085] First, reference will be made to Figure 1 Describe the electronic device according to the first example. The electronic device includes a display screen 100 and an optical fingerprint module. The display screen 100 is disposed on the object side of the optical fingerprint module. Among them, the optical fingerprint module includes an optical lens and an image sensor 150, and the image sensor 150 is disposed on the image side of the optical lens.

[0086] The optical lens according to the first example includes a first lens 110, a second lens 120, and a third lens 130.

[0087] The first lens 110 has a negative refractive power. The object surface of the first lens 110 is concave along the optical axis, and the image surface of the first lens 110 is convex along the optical axis. As Figure 1 shown, although the image surface of the first lens 110 is concave as a whole, the portion of the image surface of the first lens 110 near the optical axis is convex along the optical axis. The object surface of the second lens 120 is convex along the optical axis, and the image surface of the second lens 120 is concave along the optical axis. The object surface of the third lens 130 is convex along the optical axis, and the image surface of the third lens 130 is concave along the optical axis.

[0088] The optical lens further includes a filter 140 and a diaphragm STO. The filter 140 is disposed between the third lens 130 and the image sensor 150, and STO is disposed between the first lens 110 and the second lens 120.

[0089] The optical lens can be configured to achieve a bright optical system. For example, the F-number of the optical lens is 1.43. The optical lens can have an ultra-wide angle of view (fov), and the entire field of view of the optical lens is 126°.

[0090] In the optical lens according to the first example, the focal length f1 of the first lens is -1.03 mm, the focal length f2 of the second lens is 1.60 mm, the focal length f3 of the third lens is 0.46 mm, the total focal length (effective focal length) f of the optical lens is 0.326 mm, the distance TTL on the optical axis from the intersection of the object surface of the first lens and the optical axis to the imaging surface is 1.53 mm, BFL is 0.47 mm, and ImgH is 0.62 mm.

[0091] Table 1

[0092]

[0093]

[0094] Here, the effective radius is the clear aperture of the corresponding surface of the optical lens (the radius through which light actually passes), and the conical coefficient is the coefficient of the higher-order term in the above formula.

[0095] Among them, OBJ represents the object side or the subject, S01 and S02 respectively represent the upper surface and the lower surface of, for example, a display screen, S1 and S2 respectively represent the object-side surface and the image-side surface of the first lens, STO represents the aperture stop, S3 and S4 respectively represent the object-side surface and the image-side surface of the second lens, S5 and S6 respectively represent the object-side surface and the image-side surface of the third lens, S7 and S8 respectively represent the object-side surface and the image-side surface of the filter, and S9 represents the imaging surface.

[0096] Figure 2 The astigmatism curve of the optical lens of the first example is presented, which represents the curves of the meridional image plane curvature and the sagittal image plane curvature at 0.53 nm and 0.455 nm at different image heights; Figure 3 The distortion curve of the optical lens of the first example is presented, which represents the distortion curves at 0.53 nm and 0.455 nm at different image heights; Figure 4 The MTF curves of different image heights of the optical lens of the first example at different spatial frequencies are presented. Table 1 presents the characteristics of the lenses of the optical lens according to the first example.

[0097] will be referred to Figure 5 to describe the electronic device according to the second example. The electronic device includes a display screen 100 and an optical fingerprint module, and the display screen 100 is disposed on the object side of the optical fingerprint module. Among them, the optical fingerprint module includes an optical lens and an image sensor 250, and the image sensor 250 is disposed on the image side of the optical lens.

[0098] The optical lens according to the second example includes a first lens 210, a second lens 220, and a third lens 230.

[0099] The first lens 210 has a positive refractive power. The object-side surface of the first lens 210 is concave along the optical axis, and the image-side surface of the first lens 210 is convex along the optical axis, as Figure 5As shown, although the image-side surface of the first lens 210 is recessed as a whole, the portion of the image-side surface of the first lens 210 near the optical axis is convex along the optical axis. The object-side surface of the second lens 220 is convex along the optical axis, and the image-side surface of the second lens 220 is convex along the optical axis. The object-side surface of the third lens 230 is convex along the optical axis, and the image-side surface of the third lens 230 is recessed along the optical axis.

[0100] The optical lens further includes a filter 240 and a diaphragm STO. The filter 240 is disposed between the third lens 230 and the image sensor 250, and the STO is disposed between the first lens 210 and the second lens 220.

[0101] The optical lens can be configured to achieve a bright optical system. For example, the F-number of the optical lens is 1.51. The optical lens can have an ultra-wide-angle field of view (FOV), and the entire field of view of the optical lens is 133°.

[0102] In the optical lens according to the second example, the focal length f1 of the first lens is -1.36 mm, the focal length f2 of the second lens is 1.33 mm, the focal length f3 of the third lens is 0.53 mm, the total focal length (effective focal length) f of the optical lens is 0.353 mm, the distance TTL on the optical axis from the intersection of the object-side surface of the first lens and the optical axis to the imaging surface is 1.76 mm, the BFL is 0.46 mm, and the ImgH is 0.75 mm.

[0103] Table 2

[0104]

[0105] Here, the effective radius is the clear aperture (the radius through which light actually passes) of the corresponding surface of the optical lens, and the conic coefficient is the coefficient of the higher-order term of the above formula.

[0106] Wherein, OBJ represents the object side or the subject, S01 and S02 respectively represent the upper surface and the lower surface of, for example, a display screen, S1 and S2 respectively represent the object-side surface and the image-side surface of the first lens, STO represents the diaphragm, S3 and S4 respectively represent the object-side surface and the image-side surface of the second lens, S5 and S6 respectively represent the object-side surface and the image-side surface of the third lens, S7 and S8 respectively represent the object-side surface and the image-side surface of the filter, and S9 represents the imaging surface.

[0107] Figure 6 The astigmatism curve of the optical lens of the second example is presented, which represents the curves of the meridional image plane curvature and the sagittal image plane curvature at different image heights at 0.53 nm and 0.455 nm; Figure 7 The distortion curve of the optical lens of the second example is presented, which represents the distortion curves at different image heights at 0.53 nm and 0.455 nm; Figure 8Presents the MTF curves of different image heights of the optical lens of the second example at different spatial frequencies. Table 2 presents the characteristics of the lenses of the optical lens according to the second example.

[0108] Will refer to Figure 9 Describe an electronic device according to a third example. The electronic device includes a display screen 100 and an optical fingerprint module, and the display screen 100 is disposed on the object side of the optical fingerprint module. Among them, the optical fingerprint module includes an optical lens and an image sensor 350, and the image sensor 350 is disposed on the image side of the optical lens.

[0109] The optical lens according to the third example includes a first lens 310, a second lens 320, and a third lens 330.

[0110] The first lens 310 has a positive refractive power. The object surface of the first lens 310 is concave along the optical axis, and the image surface of the first lens 310 is convex along the optical axis. As Figure 9 shown, although the image surface of the first lens 310 is concave as a whole, the part of the image surface of the first lens 310 near the optical axis is convex along the optical axis. The object surface of the second lens 320 is convex along the optical axis, and the image surface of the second lens 320 is concave along the optical axis. The object surface of the third lens 330 is convex along the optical axis, and the image surface of the third lens 330 is concave along the optical axis.

[0111] The optical lens further includes a filter 340 and a diaphragm STO. The filter 340 is disposed between the third lens 330 and the image sensor 350, and the STO is disposed between the first lens 310 and the second lens 320.

[0112] The optical lens can be configured to implement a bright optical system. For example, the F-number of the optical lens is 1.43. The optical lens can have an ultra-wide-angle field of view (fov), and the entire field of view of the optical lens is 124°.

[0113] In the optical lens according to the third example, the focal length f1 of the first lens is -1.25 mm, the focal length f2 of the second lens is 1.95 mm, the focal length f3 of the third lens is 0.55 mm, the total focal length (effective focal length) f of the optical lens is 0.395 mm, the distance TTL on the optical axis from the intersection of the object surface of the first lens and the optical axis to the imaging surface is 1.88 mm, the BFL is 0.58 mm, and the ImgH is 0.75 mm.

[0114] Table 3

[0115]

[0116] Here, the effective radius is the net aperture (the radius through which light actually passes) of the corresponding surface of the optical lens, and the conic coefficient is the coefficient of the higher-order term in the above formula.

[0117] Among them, OBJ represents the object side or the subject, S01 and S02 respectively represent the upper surface and the lower surface of, for example, a display screen, S1 and S2 respectively represent the object-side surface and the image-side surface of the first lens, STO represents the aperture stop, S3 and S4 respectively represent the object-side surface and the image-side surface of the second lens, S5 and S6 respectively represent the object-side surface and the image-side surface of the third lens, S7 and S8 respectively represent the object-side surface and the image-side surface of the filter, and S9 represents the imaging surface.

[0118] Figure 10 The astigmatism curve of the optical lens of the third example is presented, which represents the curves of the meridional image plane curvature and the sagittal image plane curvature at 0.53 nm and 0.455 nm at different image heights; Figure 11 The distortion curve of the optical lens of the third example is presented, which represents the distortion curves at 0.53 nm and 0.455 nm at different image heights; Figure 12 The MTF curves of different image heights of the optical lens of the third example at different spatial frequencies are presented. Table 3 presents the characteristics of the lenses of the optical lens according to the third example.

[0119] Table 4 presents the values of the conditional expressions of the optical lenses according to the first example to the third example.

[0120] Table 4

[0121] Conditional / Implemental 1 2 3 TTL / f 4.69 4.99 4.76 FOV 126° 133 124° ImgH / f 1.90 2.12 1.90 TTL / CT1 8.50 8.38 8.95 (CT2 + CT3) / f 1.78 1.93 1.80 BFL / f 1.44 1.30 1.47 |f1 / f| 3.160 3.852 3.165 |f2 + f3| / f 6.32 5.27 6.33 ND1, VD1 1.54、55.9 1.54、55.9 1.54、55.9 ND2, VD2 1.54、55.9 1.54、55.9 1.54、55.9 ND3, VD3 1.64、23.5 1.64、23.5 1.64、23.5 |R11 / R12| 0.28 0.36 0.29 |R31 / R32| 0.13 0.15 0.13 |SD11 / SD21| 3.20 3.62 2

[0122] According to the above examples, miniaturization of the optical lens can be achieved while ensuring imaging performance.

[0123] Although the present disclosure includes specific examples, it will be apparent after understanding the disclosure of the present application that various changes in form and detail can be made in these examples without departing from the spirit and scope of the claims and their equivalents. The examples described herein will be considered only in a descriptive sense and not for the purpose of limitation. The description of the features or aspects in each example will be considered applicable to similar features or aspects in other examples. Appropriate results can be obtained if the described techniques are performed in a different order and / or if the components in the described system, architecture, device, or circuit are combined in a different way and / or replaced or supplemented with other components or their equivalents. Therefore, the scope of the present disclosure is not limited by the specific embodiments, but by the claims and their equivalents, and all changes within the scope of the claims and their equivalents will be construed as being included in the present disclosure.

Claims

1. An optical lens, characterized in that, The number of lenses with refractive power in the optical lens is three, and the optical lens includes: A first lens with negative refractive power; A second lens with positive refractive power; and A third lens with positive refractive power, wherein the first lens to the third lens are arranged in sequence along the direction from the object side of the optical lens to the imaging surface of the optical lens, wherein 3.5 < TTL / f < 6, and TTL < 1.95 mm, TTL is the distance on the optical axis from the intersection of the object-side surface of the first lens and the optical axis of the optical lens to the imaging surface, and f is the total focal length of the optical lens, 1.7 < (CT2 + CT3) / f < 2, wherein CT2 is the thickness on the optical axis of the central part of the second lens, and CT3 is the thickness on the optical axis of the central part of the third lens, 0.2 < |R11 / R12| < 0.4, wherein R11 is the radius of curvature of the object-side surface of the first lens, and R12 is the radius of curvature of the image-side surface of the first lens, 0.05 < |R31 / R32| < 0.25, wherein R31 is the radius of curvature of the object-side surface of the third lens, and R32 is the radius of curvature of the image-side surface of the third lens.

2. The optical lens according to claim 1, wherein The object-side surface of the first lens is concave along the optical axis.

3. The optical lens according to claim 1, characterized in that, The object-side surface of the second lens is convex along the optical axis.

4. The optical lens according to claim 1, wherein The object-side surface of the third lens is convex along the optical axis, and the image-side surface of the third lens is concave along the optical axis.

5. The optical lens according to any one of claims 1 to 4, characterized in that, 120° < fov < 140°, wherein fov is the field of view angle of the optical lens.

6. The optical lens according to any one of claims 1 to 5, characterized in that, 1.8 < ImgH / f < 2.5, wherein ImgH is half of the diagonal length of the effective imaging area of the imaging surface of the optical lens.

7. The optical lens according to any one of claims 1 to 5, characterized in that, 7 < TTL / CT1 < 9, wherein CT1 is the thickness on the optical axis of the central part of the first lens.

8. The optical lens according to any one of claims 1 to 5, characterized in that 0.9 < BFL / f < 1.6, wherein BFL is the distance from the intersection of the image-side surface of the third lens and the optical axis to the imaging surface.

9. The optical lens according to any one of claims 1 to 5, characterized in that, 2.8 < |f1| / f < 4.2, wherein f1 is the focal length of the first lens.

10. The optical lens according to any one of claims 1 to 5, characterized in that, 4.5 < |f2 + f3| / f < 6.5, wherein f2 is the focal length of the second lens, and f3 is the focal length of the third lens.

11. The optical lens according to any one of claims 1 to 5, characterized in that 1.5 < ND1 < 1.7, 1.5 < ND2 < 1.7, 1.5 < ND3 < 1.7, wherein ND1, ND2, and ND3 are the refractive indices of the first lens, the second lens, and the third lens respectively.

12. The optical lens according to any one of claims 1 to 5, characterized in that 50 < VD1 < 70, 50 < VD2 < 70, 20 < VD3 < 50, wherein VD1, VD2, and VD3 are the Abbe numbers of the first lens, the second lens, and the third lens respectively.

13. The optical lens according to any one of claims 1 to 5, characterized in that, 1.8 < |SD11 / SD21| < 4, wherein SD11 is the effective radius of the object-side surface of the first lens, and SD21 is the effective radius of the object-side surface of the second lens.

14. The optical lens according to any one of claims 1 to 5, characterized in that, The constant F-number of the optical lens satisfies: 1.3 < F-number < 1.

6.

15. An optical fingerprint module, characterized in that, The optical fingerprint module includes an image sensor and the optical lens according to any one of claims 1 to 14, and the image sensor is disposed on the image side of the optical lens.

16. An electronic device, characterized in that, The electronic device includes a display screen and the optical fingerprint module according to claim 15, and the display screen is disposed on the object side of the optical lens.

Images