A 3P ultra-wide-angle under-screen fingerprint camera

Abstract

A 3P ultra-wide-angle under-screen fingerprint lens is provided with a first lens, a second lens, a third lens and an infrared filter in sequence from the object side to the image side along the optical axis; the first lens is a biconcave negative lens, at least one side of which is an aspheric surface; the second lens is a biconvex positive lens, at least one side of which is an aspheric surface; the third lens is a biconvex positive lens, at least one side of which is an aspheric surface. The present invention provides a 3P ultra-wide-angle under-screen fingerprint lens, which meets the market development trend, uses 3 plastic lenses, has an ultra-large field of view and a large aperture, and also has good imaging quality, a small main light incident angle and high cost performance.

Description

Technical Field

[0001] The present invention relates to fingerprint unlocking, and in particular to a 3P ultra-wide-angle fingerprint lens. Background Art

[0002] With the development of science and technology, more and more science enthusiasts are conducting research on full-screen phones. Under-screen fingerprint recognition has played a role in promoting the development of full-screen phones. The advantage of under-screen fingerprint solutions is that they can be "hidden." Although they are all called under-screen fingerprint recognition, they can be divided into three types according to the technical principles and implementation methods: optical, ultrasonic, and capacitive. The three types of under-screen fingerprint recognition are different and their current development status is also different. Due to the advantages of fast, stable, and transparent light, under-screen fingerprint lenses have attracted more attention and demand from the market. In line with the goals of mobile phones such as lightness, short object distance, and excellent image quality, under-screen fingerprint lenses also need to have characteristics such as wide angle, large aperture, small distortion, high contrast, and high cost performance. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a 3P ultra-wide-angle under-screen fingerprint lens with the characteristics of large wide angle, large aperture, small distortion, high contrast and high cost performance.

[0004] To solve the above technical problems, the technical solution adopted by the present invention is: a 3P ultra-wide-angle under-screen fingerprint lens, which is provided with a first lens, a second lens, a third lens and an infrared filter in sequence along the optical axis from the object side to the image side; the first lens is a biconcave negative lens, at least one side of which is an aspherical surface; the second lens is a biconvex positive lens, at least one side of which is an aspherical surface; the third lens is a biconvex positive lens, at least one side of which is an aspherical surface.

[0005] Preferably, an aperture is provided between the first lens and the second lens.

[0006] Preferably, the following relationship is also satisfied: 1.0<|f 2 / f|<5.0, where f is the synthetic focal length of the system, and f2 is the focal length of the second lens.

[0007] Preferably, the first lens, the second lens and the third lens are made of plastic.

[0008] Preferably, the tangent angle θ of the object side edge of the second lens satisfies -18<θ<-4.

[0009] Preferably, P2(R1)>0 and P2(R2)<0 of the second lens.

[0010] Preferably, the lens satisfies: CRA<30°.

[0011] Preferably, the first lens, the second lens and the third lens are all made of plastic lenses.

[0012] This invention provides a 3P ultra-wide-angle under-screen fingerprint sensor that meets market development trends. Using three plastic lenses, it offers an ultra-wide field of view and a large aperture, while also providing excellent image quality, a small principal ray incident angle, and a high cost-performance ratio. In addition to the large aperture and high cost-performance, this 3P structure also achieves a small principal ray incident angle, facilitating optical processing of objects at short object distances. This is compatible with chips that require a small reception angle. The module chip then converts the received information into image information, achieving excellent imaging results at a certain magnification, resulting in excellent image quality. High contrast also enables more agile and accurate fingerprint recognition. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention will be further described below with reference to the accompanying drawings and examples:

[0014] Figure 1 It is a structural schematic diagram of the present invention;

[0015] Figure 2 It is a schematic diagram of the optical operation of the present invention;

[0016] Figure 3 is the field curvature diagram of Example 1;

[0017] Figure 4 is the distortion diagram of Example 1;

[0018] Figure 5 is the spherical aberration diagram of Example 1;

[0019] Figure 6 is a field curvature diagram of Example 2;

[0020] Figure 7 is the distortion diagram of Example 2;

[0021] Figure 8 is the spherical aberration diagram of Example 2;

[0022] Figure 9 This is the LAYOUT diagram of Example 3;

[0023] Figure 10 is the field curvature diagram of Example 3;

[0024] Figure 11 This is the distortion diagram of Example 3;

[0025] Figure 12 is the spherical aberration diagram of Example 3;

[0026] Figure 13 This is the LAYOUT diagram of Example 4;

[0027] Figure 14 is a field curvature diagram of Example 4;

[0028] Figure 15 is the distortion diagram of Example 4;

[0029] Figure 16 This is the spherical aberration diagram of Example 4. DETAILED DESCRIPTION

[0030] Example 1, as Figure 1 As shown, a 3P ultra-wide-angle under-screen fingerprint lens is provided with a first lens P1, a second lens P2, a third lens P3 and an infrared filter IR in sequence along the optical axis from the object side to the image side; the first lens P1 is a biconcave negative lens with at least one aspherical surface; the second lens P2 is a biconvex positive lens with at least one aspherical surface; the third lens P3 is a biconvex positive lens with at least one aspherical surface.

[0031] Preferably, an aperture STO is provided between the first lens P1 and the second lens P2.

[0032] Preferably, the following relationship is also satisfied: 1.0<|f 2 / f|<5.0, where f is the synthetic focal length of the system, and f2 is the focal length of the second lens P2.

[0033] Preferably, the first lens P1, the second lens P2 and the third lens P3 are made of plastic.

[0034] Preferably, the tangent angle θ of the object side edge of the second lens P2 satisfies -18<θP2R1<-4.

[0035] Preferably, the second lens P2 has P2(R1)>0 and P2(R2)<0. The curvature radius of the object side of P2 is P2(R1), and the curvature radius of the image side of P2 is P2(R2).

[0036] Preferably, the lens satisfies: CRA<30°. CRA is defined as the angle between the principal ray incident on the image plane and the horizontal plane.

[0037] Preferably, the first lens P1, the second lens P2, and the third lens P3 are all made of plastic lenses; more preferably, EP series, ZEONEX series, APEL series, and other resin materials can be used. This is because these materials have the following advantages over glass:

[0038] a. Light: The density of general resin lenses is 0.83-1.5, while that of optical glass is 2.27-5.95.

[0039] b. Strong impact resistance: The impact resistance of resin lenses is generally 8 to 10 kg / cm 2 , which is several times thicker than glass, so it is not easy to break, safe and durable.

[0040] c. Good light transmittance: In the visible light region, the transmittance of resin lenses is close to that of glass; in the infrared light region, it is slightly higher than that of glass; in the ultraviolet region, the transmittance decreases as the wavelength decreases starting from 0.4um, and the light with a wavelength less than 0.3um is almost completely absorbed, so the ultraviolet transmittance is poor.

[0041] d. Low cost: Injection molded lenses can be mass-produced with precision molds, and the cost per piece can be greatly reduced.

[0042] e. Ability to meet special needs: For example, the production of aspherical lenses is not difficult, while glass lenses are very difficult to make.

[0043] like Figure 2 As shown in the figure, when the lens forms an image, the object passes through the optical system and forms an inverted real image on the image plane. Then, after post-processing into electronic signal image processing, the inverted real image is captured to obtain a normal upright image.

[0044] In this embodiment, the parameters of the lens are shown in Table 1.

[0045] Table 1

[0046]

[0047] The P2R1 tangent angle θ(P2R1) is shown in Table 2.

[0048] Table 2

[0049]

[0050] In this embodiment, a first lens element P1, a second lens element P2, a third lens element P3, and an infrared filter IR are arranged in order from the object side to the image side along the optical axis. The first lens element P1 is a biconcave negative lens element with at least one aspherical surface; the second lens element P2 is a biconvex positive lens element with at least one aspherical surface; and the third lens element P3 is a biconvex positive lens element with at least one aspherical surface. The first, second, and third lenses are made of plastic.

[0051] An aperture STO is provided between the first lens P1 and the second lens P2

[0052] In this case data, |f 2 / f|=2.4044, satisfying 1.0<|f 2 / f|<5.0.

[0053] -11<θP2R1<-4.35; the tangent angle θ of the object side edge of the second lens P2 satisfies -18<θP2R1<-4.

[0054] P2(R1)=11.38, P2(R2)=-0.4474; satisfying P2(R1)>0, P2(R2<0 for the second lens

[0055] In this case, CRA=14.90°, DFOV=124.11°, and TTL=2.256mm demonstrate that this structure has the advantages of a small chief ray incident angle, a large field of view, and a short lens length.

[0056] The optical distortion curve for this case shows that the distortion values ​​for each field of view are less than 2%, and the optical distortion values ​​for the peripheral field of view are all between 1% and 2%. Therefore, the TV distortion (optical distortion change value) is constrained within the range of 0-1%, demonstrating the low distortion and the high imaging quality of this embodiment.

[0057] In this case, the spherical aberration curve shows that the spherical aberration values ​​of each point on the curve are within ±0.05, and the difference between the maximum value and the minimum value is within 0.06, which proves that the spherical aberration is small. Therefore, it is proved that this embodiment has small aberration and good imaging clarity.

[0058] like Figure 3 As shown, this is the field curvature diagram of Example 1. This curve is a field curvature curve. The field curvature values ​​of the S line and T line in each field of view are less than 0.1, and the difference between the field curvature values ​​of the S line and T line in each field of view is less than 0.1, indicating that the field curvature of this case is not large and has good center and edge resolution uniformity.

[0059] like Figure 4 As shown, this is the distortion diagram of this embodiment. This curve is the optical distortion curve. The absolute value of the distortion value of each field of view is less than 2%, and the absolute value of the optical distortion value of the peripheral field of view is all between 1% and 2%. Therefore, the TV distortion (optical distortion change value) is constrained within the range of 0-1%, proving that the distortion is small and that this embodiment has high imaging quality.

[0060] like Figure 5 As shown, this is the spherical aberration diagram of Example 1. This curve is the spherical aberration curve. The spherical aberration values ​​of each point on the curve are within ±0.04, and the difference between the maximum and minimum values ​​is within 0.06, which proves that the spherical aberration is small. Therefore, it is proved that this embodiment has small aberration and good imaging clarity.

[0061] Example 2: In this example, the structure of the lens is the same as that of Example 1. The parameters of the lens are shown in Table 3.

[0062] Table 3

[0063]

[0064] The P2R1 tangent angle θ(P2R1) is shown in Table 4.

[0065] Table 4

[0066]

[0067] In this embodiment, a first lens element P1, a second lens element P2, a third lens element P3, and an infrared filter IR are arranged in order from the object side to the image side along the optical axis. The first lens element P1 is a biconcave negative lens element with at least one aspherical surface; the second lens element P2 is a biconvex positive lens element with at least one aspherical surface; and the third lens element P3 is a biconvex positive lens element with at least one aspherical surface. The first, second, and third lenses are made of plastic.

[0068] An aperture STO is provided between the first lens P1 and the second lens P2

[0069] In this case data, |f 2 / f|=2.4094, which satisfies 1.0<|f 2 / f|<5.0.

[0070] -17.57<θP2R1<-4.81; the tangent angle θ of the object side edge of the second lens P2 satisfies -18<θP2R1<-4.

[0071] P2(R1)=29.16, P2(R2)=-0.4451; satisfying P2(R1)>0, P2(R2<0 for the second lens

[0072] In this case, CRA=16.75°, DFOV=123.37°, and TTL=2.212mm demonstrate that this structure has the advantages of a small chief ray incident angle, a large field of view, and a short lens length.

[0073] The optical distortion curve for this case shows that the absolute value of the distortion in each field of view is less than 2%, and the absolute value of the optical distortion in the peripheral field of view is all between 1% and 2%. Therefore, the TV distortion (optical distortion change) is constrained within the range of 0-1%, demonstrating the low distortion and the high imaging quality of this embodiment.

[0074] In this case, the spherical aberration curve shows that the spherical aberration values ​​of each point on the curve are within ±0.05, and the difference between the maximum value and the minimum value is within 0.06, which proves that the spherical aberration is small. Therefore, it is proved that this embodiment has small aberration and good imaging clarity.

[0075] like Figure 6 The figure below shows the field curvature of Example 2. This curve shows the field curvature value of each field of view for the S-line and T-line less than 0.1, and the difference between the field curvature values ​​of each field of view for the S-line and T-line is less than 0.1. This indicates that the field curvature of this case is not large, and the resolution uniformity between the center and the edge is good. In particular, the S-line field curvature value is close to 0 when it is close to the vertical axis, indicating almost no field curvature, which shows good uniformity.

[0076] like Figure 7The following is a distortion diagram for Example 2. This curve represents the optical distortion. The absolute value of the distortion in each field of view is less than 2%, and the absolute value of the optical distortion in the peripheral field of view is between 1% and 2%. Therefore, the TV distortion (optical distortion change) is constrained within the range of 0-1%, demonstrating low distortion and the high imaging quality of this embodiment.

[0077] like Figure 8 The figure shows the spherical aberration diagram of Example 2. This curve is the spherical aberration curve. The spherical aberration values ​​of each point on the curve are within ±0.04, and the difference between the maximum and minimum values ​​is within 0.06, which proves that the spherical aberration is small. Therefore, it proves that this embodiment has small aberration and good imaging clarity.

[0078] Example 3: This example is a counterexample and does not meet the conditions of the positive example (1. the aperture is set between P1 and P2; 2. the second lens is a biconvex positive lens with at least one aspherical surface; 3. 1.0 <|f 2 / f| < 5.0) CRA>30°.

[0079] In this embodiment, the parameters of the lens are shown in Table 5.

[0080] Table 5

[0081]

[0082]

[0083] The P2R1 tangent angle θ(P2R1) is shown in Table VI.

[0084] Table 6

[0085]

[0086] In this embodiment, a first lens element P1, a second lens element P2, a third lens element P3, and an infrared filter IR are arranged in order from the object side to the image side along the optical axis. The first lens element P1 is a biconcave negative lens element with at least one aspherical surface. The second lens element P2 is a meniscus-shaped positive lens element with a convex object side and a concave image side, and at least one aspherical surface. The third lens element P3 is a biconvex positive lens element with at least one aspherical surface. The first, second, and third lenses are made of plastic.

[0087] An aperture STO is provided between the second lens P2 and the third lens P3.

[0088] In this case data, |f 2 / f|=3.5285, satisfying 1.0<|f 2 / f|<5.0.

[0089] 15.1<θP2R1<18.3; does not satisfy the tangent angle θ of the object side edge of the second lens P2 that satisfies -18<θP2R1<-4.

[0090] P2(R1)=0.55, P2(R2)=1.29; P2(R2)<0 of the second lens is not satisfied

[0091] In this case, CRA = 33.39°, DFOV = 112.63°, and TTL = 1.983mm indicate that this structure cannot achieve the characteristics of a small chief ray incident angle and an ultra-large field of view.

[0092] The optical distortion curve of this case shows that the absolute value of its maximum field of view distortion is 2.2%, which cannot meet the distortion value requirement of less than 2%.

[0093] In this case, the spherical aberration curve shows that the spherical aberration values ​​of each point on the curve are within ±0.02, and the difference between the maximum value and the minimum value is within 0.05, which proves that the spherical aberration is small. Therefore, it is proved that this embodiment has small aberration and good imaging clarity.

[0094] like Figure 9 As shown, this is the LAYOUT diagram of Example 3, in which a first lens P1, a second lens P2, a third lens P3 and an infrared filter IR are arranged in sequence along the optical axis from the object side to the image side; the first lens P1 is a biconcave negative lens; the second lens P2 is a crescent-shaped positive lens that is convex on the object side and concave on the image side; the third lens P3 is a biconvex positive lens, and an aperture STO is provided between the second lens P2 and the third lens P3.

[0095] like Figure 10 The figure below shows the field curvature of Example 3. This curve shows the field curvature value of each field of view of the S-line and T-line less than 0.1, and the difference between the field curvature values ​​of each field of view of the S-line and T-line is less than 0.1, indicating that the field curvature of this case is not large and has good center and edge resolution uniformity. In particular, the S-line field curvature value is close to 0 when it is close to the vertical axis, indicating almost no field curvature, which shows good uniformity.

[0096] like Figure 11 The figure shows the distortion diagram of Example 3. This curve is an optical distortion curve, and the absolute value of the maximum field distortion is 2.2%, which is a relatively large distortion value.

[0097] like Figure 12 As shown, this is the spherical aberration diagram of Example 3. This curve is the spherical aberration curve. The spherical aberration values ​​of each point on the curve are within ±0.02, and the difference between the maximum and minimum values ​​is within 0.05, which proves that the spherical aberration is small. Therefore, it is proved that this embodiment has small aberration and good imaging clarity.

[0098] Example 4: This example is a counterexample and does not meet the conditions of the positive example (1. the aperture is set between P1 and P2; 2. the second lens is a biconvex positive lens with at least one aspherical surface; 3. 1.0 < |f 2 / f| < 5.0) CRA> 30°.

[0099] In this embodiment, the parameters of the lens are shown in Table 7.

[0100] Table 7

[0101]

[0102] The P2R1 tangent angle θ(P2R1) is shown in Table 8.

[0103]

[0104] In this embodiment, a first lens element P1, a second lens element P2, a third lens element P3, and an infrared filter IR are arranged in order from the object side to the image side along the optical axis. The first lens element P1 is a biconcave negative lens element with at least one aspherical surface. The second lens element P2 is a meniscus-shaped positive lens element with a convex object side and a concave image side, and at least one aspherical surface. The third lens element P3 is a biconvex positive lens element with at least one aspherical surface. The first, second, and third lenses are made of plastic.

[0105] An aperture STO is provided between the second lens P2 and the third lens P3.

[0106] In this case data, |f 2 / f| = 5.1959, which does not satisfy 1.0 < |f 2 / f| < 5.0.

[0107] 12.59<θP2R1<16.62; the tangent angle θ of the object side edge of the second lens P2 does not satisfy -18<θP2R1<-4.

[0108] P2(R1)=0.7, P2(R2)=1.32; P2(R2)<0 of the second lens is not satisfied

[0109] In this case, CRA = 36.32°, DFOV = 121.83°, and TTL = 2.136 mm indicate that this structure cannot have the characteristics of a small chief ray incident angle.

[0110] The optical distortion curve of this case shows that the absolute value of its maximum field of view distortion is 2.5%, which cannot meet the distortion value requirement of less than 2%.

[0111] In this case, the spherical aberration curve shows that the spherical aberration values ​​of each point on the curve are within ±0.02, and the difference between the maximum value and the minimum value is within 0.05, which proves that the spherical aberration is small. Therefore, it is proved that this embodiment has small aberration and good imaging clarity.

[0112] like Figure 13As shown, this is the LAYOUT diagram of Example 4, in which a first lens P1, a second lens P2, a third lens P3 and an infrared filter IR are arranged in sequence along the optical axis from the object side to the image side; the first lens P1 is a biconcave negative lens; the second lens P2 is a crescent-shaped positive lens that is convex on the object side and concave on the image side; the third lens P3 is a biconvex positive lens, and an aperture STO is provided between the second lens P2 and the third lens P3.

[0113] like Figure 14 The figure shows the field curvature of Example 4. This curve is a field curvature curve. The field curvature values ​​of the S-line and T-line fields are less than 0.1, and the difference between the field curvature values ​​of the S-line and T-line fields is less than 0.1. This shows that the field curvature of this case is not large and has good center and edge resolution uniformity.

[0114] like Figure 15 The figure shows the distortion diagram of Example 4. This curve is an optical distortion curve, and the absolute value of the maximum field distortion is 2.5%, which is a relatively large distortion value.

[0115] like Figure 16 The figure shows the spherical aberration diagram of Example 4. This curve is the spherical aberration curve. The spherical aberration values ​​of each point on the curve are within ±0.05, but the difference between the maximum and minimum values ​​exceeds 0.06, which proves that the aberration of this embodiment is large and the image is blurred.

[0116] Due to the characteristics of the present invention, a total of three plastic lenses are used, with a "-, +, +" lens group structure, where the aperture (STO) is between the first lens (P1) and the second lens (P2); the second lens P2 is a double-convex positive lens, and aspheric mold manufacturing technology is utilized to mass-produce aspheric plastic lenses, reducing costs and obtaining a better assembly process, so that this lens has the advantages of wide angle, large aperture, small distortion, high contrast, high cost performance and the like.

[0117] The above embodiments are merely preferred technical solutions of the present invention and should not be construed as limiting the present invention. The scope of protection of the present invention shall be the technical solutions set forth in the claims, including equivalent alternatives to the technical features of the technical solutions set forth in the claims. In other words, equivalent alternatives and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A 3P ultra-wide-angle under-screen fingerprint camera, characterized by: A first lens (P1), a second lens (P2), a third lens (P3) and an infrared filter (IR) are arranged in sequence from the object side to the image side along the optical axis; the first lens (P1) is a biconcave negative lens, at least one side of which is an aspheric surface; the second lens (P2) is a biconvex positive lens, at least one side of which is an aspheric surface; the third lens (P3) is a biconvex positive lens, at least one side of which is an aspheric surface; an aperture (STO) is arranged between the first lens (P1) and the second lens (P2); the following relationship is also satisfied: 1.0<|f2 / f|<5.0, where f is the synthetic focal length of the system and f2 is the focal length of the second lens (P2); the tangent angle θ of the object side edge of the second lens (P2) satisfies -18°<θ<-4°; the lens satisfies: CRA<30°; the first lens (P1), the second lens (P2) and the third lens (P3) are lenses made of plastic.

Images