Optical lens, optical fingerprint module and electronic equipment

Abstract

The utility model relates to the field of optics, in particular to an optical lens, an optical fingerprint module and electronic equipment. The optical lens is configured between a screen and an imaging surface of the optical lens, the optical lens comprises three lenses, and the three lenses are a first lens, a second lens and a third lens; the first lens, the second lens and the third lens are sequentially arranged along the optical axis of the optical lens in the direction from the object side to the imaging surface of the optical lens. The first lens has negative focal power, the second lens has positive focal power, and the third lens has positive focal power; the optical lens meets the condition that the ratio of ObjH to ImgH is larger than or equal to 6.5 and smaller than or equal to 7.5, ObjH is the object height corresponding to half of the maximum field angle of the optical lens, and ImgH is the image height corresponding to half of the maximum field angle of the optical lens. According to the optical lens, the imaging performance can be ensured to a certain extent.

Description

Technical Field

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

[0002] In recent years, with the rapid development of full-screen technology, it has become a technological trend to equip electronic devices with screen fingerprint recognition devices. In particular, optical fingerprint recognition has significant advantages in enhancing the appearance, user experience, and security of devices. However, currently, when the optical lens of optical fingerprint recognition is imaging, there are problems such as uneven light emission from the screen to under the screen and low transmittance, resulting in a large decline in imaging quality.

[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 the prior art that may be taught to those of ordinary skill in the art. Summary of the Utility Model

[0004] The summary of the utility model is provided to introduce in a simplified form selected concepts that will be further described in the detailed implementation below. The summary of the utility model is neither intended to identify the key features or essential features of the claimed subject matter nor intended to be used to help determine the scope of the claimed subject matter.

[0005] The present utility model provides an optical lens, an optical fingerprint module, and an electronic device, which can effectively ensure imaging performance.

[0006] A first aspect of the present utility model provides an optical lens, which is configured between a screen and an imaging surface of the optical lens. The optical lens includes three lenses, and the three lenses are a first lens, a second lens, and a third lens;

[0007] The first lens, the second lens, and the third lens are sequentially arranged along the optical axis of the optical lens from the object side to the imaging surface direction of the optical lens;

[0008] The first lens has a negative optical power, the second lens has a positive optical power, and the third lens has a positive optical power;

[0009] The optical lens satisfies: 6.5 ≤ ObjH / ImgH ≤ 7.5, where ObjH is the object height corresponding to half of the maximum field of view angle of the optical lens, and ImgH is the image height corresponding to half of the maximum field of view angle of the optical lens.

[0010] Further, the object side surface of the first lens is convex along the optical axis of the optical lens, and the image side surface of the first lens is concave along the optical axis;

[0011] The object surface of the second lens is convex along the optical axis, and the image surface of the second lens is concave along the optical axis;

[0012] The object surface of the third lens is convex along the optical axis, and the image surface of the third lens is convex along the optical axis.

[0013] Furthermore, the optical lens further includes an aperture stop, and the aperture stop is disposed between the second lens and the third lens.

[0014] Furthermore, the optical lens further includes a filter, and the filter is disposed on one side of the image surface of the third lens.

[0015] Furthermore, the optical lens satisfies: 6 ≤ TTL / f ≤ 7;

[0016] Wherein, TTL is the distance from the object surface of the first lens to the imaging surface of the optical lens on the optical axis, and f is the effective focal length of the optical lens.

[0017] Furthermore, the optical lens satisfies: TTL ≤ 2.5 mm;

[0018] Wherein, TTL is the distance from the object surface of the first lens to the imaging surface of the optical lens on the optical axis.

[0019] Furthermore, the optical lens satisfies: fov ≥ 110°;

[0020] Wherein, fov is the field of view angle of the optical lens.

[0021] Furthermore, the optical lens satisfies: 1.0 ≤ ImgH / f ≤ 2.0;

[0022] Wherein, ImgH is the image height corresponding to half of the maximum field of view angle of the optical lens, and f is the effective focal length of the optical lens.

[0023] Furthermore, the optical lens satisfies: 1 ≤ (CT1 + CT2) / f ≤ 1.5;

[0024] Wherein, CT1 is the central thickness of the first lens on the optical axis, CT2 is the central thickness of the second lens on the optical axis, and f is the effective focal length of the optical lens.

[0025] Furthermore, the optical lens satisfies: 5 ≤ TTL / CT3 ≤ 6;

[0026] Wherein, CT3 is the central thickness of the third lens on the optical axis, and TTL is the distance from the object surface of the first lens to the imaging surface of the optical lens on the optical axis.

[0027] Further, the optical lens satisfies: 5.5 ≤ (f2 + f3) / f ≤ 7;

[0028] Wherein, f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, and f is the effective focal length of the optical lens.

[0029] Further, the optical lens satisfies: f / EPD ≤ 2;

[0030] Wherein, EPD is the entrance pupil diameter of the optical lens, and f is the effective focal length of the optical lens.

[0031] Further, the optical lens satisfies: 2 ≤ BFL / f ≤ 3;

[0032] Wherein, BFL is the distance from the image surface of the third lens to the imaging surface of the optical lens on the optical axis, and f is the effective focal length of the optical lens.

[0033] Further, the optical lens satisfies:

[0034] 1.5 ≤ ND1 ≤ 1.6, 20 ≤ VD1 ≤ 70;

[0035] 1.5 ≤ ND2 ≤ 1.6, 20 ≤ VD2 ≤ 70;

[0036] 1.5 ≤ ND3 ≤ 1.6, 20 ≤ VD3 ≤ 70;

[0037] ND1 is the refractive index of the first lens, and VD1 is the Abbe number of the first lens;

[0038] ND2 is the refractive index of the second lens, and VD2 is the Abbe number of the second lens;

[0039] ND3 is the refractive index of the third lens, and VD3 is the Abbe number of the third lens.

[0040] The second aspect of the present invention provides an optical fingerprint module, including an image sensor and the optical lens as described above, and the image sensor is disposed on the image side of the optical lens.

[0041] The third aspect of the present invention provides an electronic device, including 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.

[0042] Compared with the prior art, the beneficial effects of the present invention are:

[0043] The optical lens provided by the present utility model is configured between a screen and an imaging surface of the optical lens. The optical lens includes three lenses, namely a first lens, a second lens, and a third lens. The first lens, the second lens, and the third lens are sequentially arranged along the optical axis of the optical lens from the object side to the imaging surface. The first lens has a negative focal power, the second lens has a positive focal power, and the third lens has a positive focal power. The optical lens satisfies: 6.5 ≤ ObjH / ImgH ≤ 7.5, where ObjH is the object height corresponding to half of the maximum field of view angle of the optical lens, and ImgH is the image height corresponding to half of the maximum field of view angle of the optical lens. According to the optical lens of the present application, the imaging performance can be guaranteed to a certain extent.

[0044] The present utility model also provides an optical fingerprint module, which includes an image sensor and the optical lens as described above. The image sensor is disposed on the image side of the optical lens. The optical fingerprint module includes the optical lens as described above, so the optical fingerprint module also has the beneficial effects of the optical lens.

[0045] The present utility model also provides an electronic device, which includes a display screen and the optical fingerprint module as described above. The display screen is disposed on the object side of the optical lens. The electronic device includes the optical fingerprint module provided with the above optical lens, so it also has the beneficial effects of the optical lens. Description of the Drawings

[0046] In order to more clearly illustrate the specific embodiments of the present utility model or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0047] Figure 1 It is a view showing a first example of an electronic device having an optical lens.

[0048] Figure 2 Present Figure 1 The astigmatism curve of the shown optical lens.

[0049] Figure 3 Present Figure 1 The distortion curve of the shown optical lens.

[0050] Figure 4 Present Figure 1 The MTF curve of the shown optical lens.

[0051] Figure 5 Present Figure 1 the illuminance curve of the optical lens shown.

[0052] Figure 6 is a diagram showing two examples of an electronic device having an optical lens.

[0053] Figure 7 Present Figure 6 the astigmatism curve of the optical lens shown.

[0054] Figure 8 Present Figure 6 the distortion curve of the optical lens shown.

[0055] Figure 9 Present Figure 6 the MTF curve of the optical lens shown.

[0056] Figure 10 Present Figure 6 the illuminance curve of the optical lens shown.

[0057] Figure 11 is a diagram showing a third example of an electronic device having an optical lens.

[0058] Figure 12 Present Figure 11 the astigmatism curve of the optical lens shown.

[0059] Figure 13 Present Figure 11 the distortion curve of the optical lens shown.

[0060] Figure 14 Present Figure 11 the MTF curve of the optical lens shown.

[0061] Figure 15 Present Figure 11 the illuminance curve of the optical lens shown.

[0062] Reference numerals:

[0063] In Figure 1 : 100 - display screen, 110 - first lens, 120 - second lens, 130 - third lens, 140 - filter, 150 - image sensor, STO - aperture stop;

[0064] In Figure 6 : 200 - display screen, 210 - first lens, 220 - second lens, 230 - third lens, 240 - filter, 250 - image sensor, STO - aperture stop;

[0065] In Figure 11In the figure: 300 - display screen, 310 - first lens, 320 - second lens, 330 - third lens, 340 - filter, 350 - image sensor, STO - aperture stop. Detailed implementation

[0066] The following detailed implementation is provided to help readers obtain a comprehensive understanding of the methods, devices, and / or systems described herein. However, after understanding the disclosure of this 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 an example and is not limited to the order set forth herein. Rather, changes that will be apparent after understanding the disclosure of this 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.

[0067] 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 are 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 this application.

[0068] The first aspect of this application provides an optical lens.

[0069] In an embodiment of this 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 this 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), the image height (ImgH) corresponding to half of the maximum field of view angle of the optical lens, the object height (ObjH) corresponding to half of the maximum field of view angle of the optical lens, the entrance pupil diameter (EPD) of the optical lens, the distance from the image surface of the third lens to the imaging surface (BFL), and the focal length are all expressed in millimeters (mm).

[0070] 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.

[0071] The optical lens provided by this application includes three lenses; for example, the optical lens includes a first lens, a second lens, and a third lens sequentially arranged along the optical axis of the optical lens from the object side of the optical lens to the imaging surface.

[0072] The first lens has a focal power; for example, the first lens has a negative focal power. The second lens has a focal power; for example, the second lens has a positive focal power. The third lens has a focal power; for example, the third lens has a positive focal power.

[0073] In some embodiments, the object-side surface of the first lens is convex along the optical axis, and the image-side surface of the first lens is concave along the optical axis; the object-side surface of the second lens is convex along the optical axis, and the image-side surface of the second lens is concave along the optical axis; the object-side surface of the third lens is convex along the optical axis, and the image-side surface of the third lens is convex along the optical axis.

[0074] The first lens, the second lens, and the third lens are all aspherical mirrors; for example, the object-side surface and the image-side surface of the first lens, the object-side surface and the image-side surface of the second lens, and the object-side surface and the image-side surface of the third lens are all aspherical surfaces.

[0075] Any aspherical surface of the first lens, the second lens, and the third lens can be expressed by the following expression:

[0076]

[0077] Wherein, 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.

[0078] In some embodiments, the optical lens may further include a diaphragm and / or a filter.

[0079] The diaphragm is disposed between the second lens and the third lens. Setting the diaphragm at this position can better control the light input, better increase the illuminance, and improve the imaging quality.

[0080] The filter is disposed on the image-side of the third lens, that is, the filter is disposed between the third lens and the image sensor described below. The filter is used to block light of some wavelengths to facilitate clear imaging. For example, the filter is an infrared filter to block infrared-wavelength light through the filter.

[0081] The second aspect of this application relates to an optical fingerprint module, wherein the optical fingerprint module includes an image sensor and the optical lens described in the first aspect above, and the image sensor is disposed on the image-side of the optical lens.

[0082] The image sensor can form an imaging surface; for example, the surface of the photosensitive pixel array of the image sensor can form the imaging surface.

[0083] The third aspect of the present application relates to 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. Here, the electronic device can be a portable or mobile terminal such as a mobile phone, a tablet computer, a gaming device, etc. In the electronic device, the optical fingerprint module is disposed under the display screen for receiving a light beam carrying fingerprint information, and 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.

[0084] In the optical lens, the optical fingerprint module, and the electronic device involved in the present disclosure, the following conditional expressions can be satisfied:

[0085] In some embodiments, 6.5 ≤ ObjH / ImgH ≤ 7.5 is satisfied.

[0086] In some embodiments, 6 ≤ TTL / f ≤ 7 is satisfied.

[0087] In some embodiments, TTL ≤ 2.5 mm is satisfied.

[0088] In some embodiments, fov ≥ 110° is satisfied.

[0089] In some embodiments, 1.0 ≤ ImgH / f ≤ 2.0 is satisfied.

[0090] In some embodiments, 1 ≤ (CT1 + CT2) / f ≤ 1.5 is satisfied.

[0091] In some embodiments, 5 ≤ TTL / CT3 ≤ 6 is satisfied.

[0092] In some embodiments, 5.5 ≤ (f2 + f3) / f ≤ 7 is satisfied.

[0093] In some embodiments, f / EPD ≤ 2 is satisfied.

[0094] In some embodiments, 2 ≤ BFL / f ≤ 3 is satisfied.

[0095] In some embodiments, 1.5 ≤ ND1 ≤ 1.6 is satisfied.

[0096] In some embodiments, 1.5 ≤ ND2 ≤ 1.6 is satisfied.

[0097] In some embodiments, 1.5 ≤ ND3 ≤ 1.6 is satisfied.

[0098] In some embodiments, 20 ≤ VD1 ≤ 70 is satisfied.

[0099] In some embodiments, 20 ≤ VD2 ≤ 70 is satisfied.

[0100] In some embodiments, 20 ≤ VD3 ≤ 70 is satisfied.

[0101] In the above expressions:

[0102] ObjH is the object height corresponding to half of the maximum field of view angle of the optical lens, ImgH is the image height corresponding to half of the maximum field of view angle of the optical lens, TTL is the distance from the object-side surface of the first lens to the imaging surface of the optical lens on the optical axis, f is the effective focal length of the optical lens, fov is the field of view angle of the optical lens, ImgH is the image height corresponding to half of the maximum field of view angle of the optical lens, CT1 is the central thickness of the first lens on the optical axis, CT2 is the central thickness of the second lens on the optical axis, CT3 is the central thickness of the third lens on the optical axis, f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, EPD is the entrance pupil diameter of the optical lens, BFL is the distance from the image-side surface of the third lens to the imaging surface of the optical lens on the optical axis, ND1 is the refractive index of the first lens, VD1 is the Abbe number of the first lens, ND2 is the refractive index of the second lens, VD2 is the Abbe number of the second lens, ND3 is the refractive index of the third lens, and VD3 is the Abbe number of the third lens.

[0103] Here, according to 6.5 ≤ ObjH / ImgH ≤ 7.5, it is possible to ensure that the optical lens has more fingerprint information.

[0104] In addition, according to 6 ≤ TTL / f ≤ 7 and TTL ≤ 2.5, it is possible to miniaturize the optical lens while ensuring imaging performance.

[0105] In addition, according to fov ≥ 110°, it is possible to ensure the wide-angle characteristics of the optical lens, increase the imaging range of the optical lens, and improve the fingerprint recognition ability.

[0106] In addition, according to 1 ≤ ImgH / f ≤ 2, it is possible to ensure the wide-angle characteristics of the optical lens, reduce the size of the image sensor to reduce costs.

[0107] In addition, according to 1 ≤ (CT1 + CT2) / f ≤ 1.5, it is possible to reduce the thickness of the optical lens and effectively control the total length of the optical lens.

[0108] In addition, according to 5 ≤ TTL / CT3 ≤ 6, the thickness of the optical lens can be reduced, and the total length of the optical lens can be effectively controlled.

[0109] In addition, according to 5.5 ≤ (f2 + f3) / f ≤ 7, the optical lens can be ensured to have a reasonable optical power, which is beneficial to improving the imaging quality of the optical lens and reducing the sensitivity.

[0110] In addition, according to f / EPD ≤ 2, it is beneficial to improving the imaging quality of the optical lens.

[0111] In addition, according to 2 ≤ BFL / f ≤ 3, it is beneficial to realizing the miniaturization of the optical lens and enabling the optical lens to have a larger imaging range.

[0112] In addition, according to 1.5 ≤ ND1 ≤ 1.6, 1.5 ≤ ND2 ≤ 1.6, 1.5 ≤ ND3 ≤ 1.6, 20 ≤ VD1 ≤ 70, 20 ≤ VD2 ≤ 70, and 20 ≤ VD3 ≤ 70, the central thickness of the optical lens can be effectively controlled, the processing difficulty of each lens can be reduced, and it is beneficial to eliminating the chromatic aberration of the optical lens and improving the imaging quality of the optical lens.

[0113] Next, electronic devices according to several examples will be described.

[0114] First, reference will be made to Figure 1 Describe an 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. 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.

[0115] The optical lens according to the first example includes a first lens 110, a second lens 120, and a third lens 130. The first lens 110 has a negative optical power. The object surface of the first lens 110 is convex along the optical axis, and the image surface of the first lens 110 is concave along the optical axis. The second lens 120 has a positive optical power. The object surface of the second lens 120 is convex along the optical axis, and the image surfaces of the second lens 120 are both concave along the optical axis. The third lens 130 has a positive optical power. The object surface of the third lens 130 is convex along the optical axis, and the image surface of the third lens 130 is also convex along the optical axis. The optical lens further includes a diaphragm STO and a filter 140. The diaphragm STO is disposed between the second lens 120 and the third lens 130, and the filter 140 is disposed between the third lens 130 and the image sensor 150.

[0116] In the optical lens according to the first example, the focal length f1 of the first lens is -0.727 mm, the focal length f2 of the second lens is 1.509 mm, the focal length f3 of the third lens is 0.556 mm, the total focal length (effective focal length) f of the optical lens is 0.358 mm, the TTL of the optical lens is 2.168 mm, the field of view angle fov of the optical lens is 124°, the magnification Magnification (ObjH / ImgH) of the optical lens is 6.937, the entrance pupil diameter EPD of the optical lens is 0.265 mm, the refractive index ND1 of the first lens is 1.54 mm, the Abbe number VD1 of the first lens is 55.8 mm, the refractive index ND2 of the second lens is 1.54 mm, the Abbe number VD2 of the second lens is 55.8 mm, the refractive index ND3 of the third lens is 1.54 mm, and the Abbe number VD3 of the third lens is 55.8 mm.

[0117] Table 1

[0118] Serial number Surface type Radius of curvature Thickness ND VD Conic coefficient OBJ Standard surface Infinity 0.000 0.00 S01 Standard surface Infinity 1.200 1.52 64.17 0.00 S02 Standard surface Infinity 1.492 0.00 S1 Aspherical surface 10.87 0.216 1.54 55.80 100.00 S2 Aspherical surface 0.38 0.430 -1.47 S3 Aspherical surface 0.80 0.264 -0.60 S4 Aspherical surface 19.45 0.042 1.54 55.80 0.00 STO Standard surface Infinity 0.048 0.00 S5 Aspherical surface 1.48 0.395 1.54 55.80 -2.55 S6 Aspherical surface -0.35 0.490 -7.07 S7 Standard surface Infinity 0.210 1.52 64.17 0.00 S8 Standard surface Infinity 0.072 0.00 S9 Standard surface Infinity 0.000 0.00

[0119] Here, the conic coefficient is the high-order term coefficient of the above formula.

[0120] 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, S3 and S4 respectively represent the object-side surface and the image-side surface of the second lens, STO represents the aperture stop, 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.

[0121] 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 different image heights at 0.537 nm, 0.58 nm, and 0.46 nm; Figure 3 The distortion curve of the optical lens of the first example is presented, which represents the distortion curves at different image heights at 0.537 nm, 0.58 nm, and 0.46 nm; Figure 4 The MTF curves of different image heights of the optical lens of the first example at different spatial frequencies are presented. Figure 5 The illuminance curve of the optical lens of the first example is presented. Table 1 presents the characteristics of the lenses of the optical lens according to the first example.

[0122] will refer to Figure 6Describe the electronic device according to the second example. The electronic device includes a display screen 200 and an optical fingerprint module, and the display screen 200 is disposed on the object side of the optical fingerprint module. 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.

[0123] The optical lens according to the second example includes a first lens 210, a second lens 220, and a third lens 230. The first lens 210 has a negative optical power. The object surface of the first lens 210 is convex along the optical axis, and the image surface of the first lens 210 is concave along the optical axis. The second lens 220 has a positive optical power. The object surface of the second lens 220 is convex along the optical axis, and the image surfaces of the second lens 220 are both concave along the optical axis. The third lens 230 has a positive optical power. The object surface of the third lens 230 is convex along the optical axis, and the image surface of the third lens 230 is also convex along the optical axis. The optical lens further includes a stop STO and a filter 240. The stop STO is disposed between the second lens 220 and the third lens 230, and the filter 240 is disposed between the third lens 230 and the image sensor 250.

[0124] In the optical lens according to the second example, the focal length f1 of the first lens is -0.708 mm, the focal length f2 of the second lens is 1.580 mm, the focal length f3 of the third lens is 0.604 mm, the total focal length (effective focal length) f of the optical lens is 0.354 mm, the TTL of the optical lens is 2.390 mm, the field of view angle fov of the optical lens is 110°, the magnification Magnification (ObjH / ImgH) of the optical lens is 6.647, the entrance pupil diameter EPD of the optical lens is 0.20 mm, the refractive index ND1 of the first lens is 1.54 mm, the Abbe number VD1 of the first lens is 55.8 mm, the refractive index ND2 of the second lens is 1.64 mm, the Abbe number VD2 of the second lens is 23.5 mm, the refractive index ND3 of the third lens is 1.54 mm, and the Abbe number VD3 of the third lens is 55.8 mm.

[0125] Table 2

[0126] Serial number Surface type Radius of curvature Thickness ND VD Conic coefficient OBJ Standard surface Infinity 0.000 0.00 S01 Standard surface Infinity 1.200 1.52 64.17 0.00 S02 Standard surface Infinity 1.641 0.00 S1 Aspherical surface 10.67 0.216 1.54 55.80 100.00 S2 Aspherical surface 0.37 0.530 -1.47 S3 Aspherical surface 0.83 0.255 -0.60 S4 Aspherical surface 20.04 0.059 1.54 55.80 0.00 STO Standard surface Infinity 0.036 0.00 S5 Aspherical surface 3.32 0.430 1.54 55.80 -2.55 S6 Aspherical surface -0.35 0.475 -7.07 S7 Standard surface Infinity 0.210 1.52 64.17 0.00 S8 Standard surface Infinity 0.178 0.00 S9 Standard surface Infinity 0.000 0.00

[0127] Here, the conic coefficient is the high-order term coefficient of the above formula.

[0128] 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, S3 and S4 respectively represent the object-side surface and the image-side surface of the second lens, STO represents the aperture stop, 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.

[0129] Figure 7 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 0.537 nm, 0.58 nm, and 0.46 nm at different image heights; Figure 8 The distortion curve of the optical lens of the second example is presented, which represents the distortion curves at different image heights at 0.537 nm, 0.58 nm, and 0.46 nm; Figure 9 The MTF curves of different image heights of the optical lens of the second example at different spatial frequencies are presented. Figure 10 The illuminance curve of the optical lens of the second example is presented. Table 2 presents the characteristics of the lenses of the optical lens according to the second example.

[0130] Reference will be made to Figure 11 Describe the electronic device according to the third example. The electronic device includes a display screen 300 and an optical fingerprint module. The display screen 300 is disposed on the object side of the optical fingerprint module. 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.

[0131] The optical lens according to the second example includes a first lens 310, a second lens 320, and a third lens 330. The first lens 310 has a negative optical power. The object-side surface of the first lens 310 is convex along the optical axis, and the image-side surface of the first lens 310 is concave along the optical axis. The second lens 320 has a positive optical power. The object-side surface of the second lens 320 is convex along the optical axis, and the image-side surfaces of the second lens 320 are both concave along the optical axis. The third lens 330 has a positive optical power. The object-side surface of the third lens 330 is convex along the optical axis, and the image-side surface of the third lens 330 is also convex along the optical axis. The optical lens further includes a stop STO and a filter 340. The stop STO is disposed between the second lens 320 and the third lens 330, and the filter 340 is disposed between the third lens 330 and the image sensor 350.

[0132] In the optical lens according to the third example, the focal length f1 of the first lens is -0.731 mm, the focal length f2 of the second lens is 1.556 mm, the focal length f3 of the third lens is 0.557 mm, the total focal length (effective focal length) f of the optical lens is 0.353 mm, the TTL of the optical lens is 2.214 mm, the field of view angle fov of the optical lens is 126°, the magnification Magnification (ObjH / ImgH) of the optical lens is 7.250, the entrance pupil diameter EPD of the optical lens is 0.220 mm, the refractive index ND1 of the first lens is 1.54 mm, the Abbe number VD1 of the first lens is 55.8 mm, the refractive index ND2 of the second lens is 1.54 mm, the Abbe number VD2 of the second lens is 55.8 mm, the refractive index ND3 of the third lens is 1.54 mm, and the Abbe number VD3 of the third lens is 55.8 mm.

[0133] Table 3

[0134]

[0135]

[0136] Here, the conic coefficient is the coefficient of the higher-order term in the above formula.

[0137] 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, S3 and S4 respectively represent the object-side surface and the image-side surface of the second lens, STO represents the aperture stop, 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.

[0138] Figure 12 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 different image heights at 0.537 nm, 0.58 nm, and 0.46 nm; Figure 13 The distortion curve of the optical lens of the third example is presented, which represents the distortion curves at different image heights at 0.537 nm, 0.58 nm, and 0.46 nm; Figure 14 The MTF curves of different image heights of the optical lens of the third example at different spatial frequencies are presented. Figure 15 The illuminance curve of the optical lens of the third example is presented. Table 3 presents the characteristics of the lenses of the optical lens according to the third example.

[0139] Table 4 presents the values of the conditional expressions of the optical lenses according to the first example, the second example, and the third example.

[0140] Table 4

[0141]

[0142]

[0143] According to the above examples, the cost can be reduced while ensuring the imaging performance.

[0144] 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 purposes of limitation. The description of a feature or aspect in each example will be considered applicable to a similar feature or aspect 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 is defined 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: Used to be arranged between the screen and the imaging surface of the optical lens, wherein the optical lens comprises three lenses, and the three lenses are a first lens, a second lens and a third lens; The first lens, the second lens and the third lens are sequentially arranged along the optical axis of the optical lens from the object side to the imaging surface of the optical lens; The first lens has negative optical power, the second lens has positive optical power, and the third lens has positive optical power; The optical lens satisfies: 6.5≤ObjH / ImgH≤7.5, wherein ObjH is the object height corresponding to half of the maximum field angle of the optical lens, and ImgH is the image height corresponding to half of the maximum field angle of the optical lens.

2. The optical lens according to claim 1, characterized in that: The object-side surface of the first lens is convex along the optical axis of the optical lens, and the image-side surface of the first lens is concave along the optical axis; The object-side surface of the second lens is convex along the optical axis, and the image-side surface of the second lens is concave along the optical axis; The object-side surface of the third lens is convex along the optical axis, and the image-side surface of the third lens is convex along the optical axis.

3. The optical lens according to claim 1, characterized in that: The optical lens further includes an aperture stop, and the aperture stop is disposed between the second lens and the third lens.

4. The optical lens according to claim 1, characterized in that: The optical lens further includes a filter, which is arranged on one side of the image-side surface of the third lens.

5. The optical lens according to any one of claims 1 to 4, characterized in that: The optical lens satisfies: 6≤TTL / f≤7; Wherein, TTL is the distance from the object surface of the first lens to the imaging surface of the optical lens on the optical axis, and f is the effective focal length of the optical lens.

6. The optical lens according to any one of claims 1 to 4, characterized in that: The optical lens meets the following requirements: TTL≤2.5mm; Wherein, TTL is the distance from the object surface of the first lens to the imaging surface of the optical lens on the optical axis.

7. The optical lens according to any one of claims 1 to 4, characterized in that: The optical lens meets the following requirements: fov≥110°; Wherein, fov is the field of view of the optical lens.

8. The optical lens according to any one of claims 1 to 4, characterized in that: The optical lens satisfies: 1.0≤ImgH / f≤2.0; Wherein, ImgH is the image height corresponding to half of the maximum field angle of the optical lens, and f is the effective focal length of the optical lens.

9. The optical lens according to any one of claims 1 to 4, characterized in that: The optical lens satisfies: 1≤(CT1+CT2) / f≤1.5; Wherein, CT1 is the center thickness of the first lens on the optical axis, CT2 is the center thickness of the second lens on the optical axis, and f is the effective focal length of the optical lens.

10. The optical lens according to any one of claims 1 to 4, characterized in that: The optical lens meets the following requirements: 5≤TTL / CT3≤6; Wherein, CT3 is the center thickness of the third lens on the optical axis, and TTL is the distance from the object surface of the first lens to the imaging surface of the optical lens on the optical axis.

11. The optical lens according to any one of claims 1 to 4, characterized in that: The optical lens satisfies: 5.5≤(f2+f3) / f≤7; Among them, f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, and f is the effective focal length of the optical lens.

12. The optical lens according to any one of claims 1 to 4, characterized in that: The optical lens satisfies: f / EPD≤2; Wherein, EPD is the entrance pupil diameter of the optical lens, and f is the effective focal length of the optical lens.

13. The optical lens according to any one of claims 1 to 4, characterized in that: The optical lens satisfies: 2≤BFL / f≤3; Wherein, BFL is the distance from the image surface of the third lens to the imaging surface of the optical lens on the optical axis, and f is the effective focal length of the optical lens.

14. The optical lens according to any one of claims 1 to 4, characterized in that: The optical lens meets the following requirements: 1.5≤ND1≤1.6, 20≤VD1≤70; 1.5≤ND2≤1.6, 20≤VD2≤70; 1.5≤ND3≤1.6, 20≤VD3≤70; ND1 is the refractive index of the first lens, VD1 is the Abbe number of the first lens; ND2 is the refractive index of the second lens, and VD2 is the Abbe number of the second lens; ND3 is the refractive index of the third lens, and VD3 is the Abbe number of the third lens.

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

16. An electronic device, characterized in that: It comprises a display screen and the optical fingerprint module as claimed in claim 15, wherein the display screen is arranged on the object side of the optical lens.

Images