CN110780421B

CN110780421B - A 3P ultra-wide-angle under-screen fingerprint camera

Info

Publication number: CN110780421B
Application number: CN201910990030.4A
Authority: CN
Inventors: 陈俊宏; 温小利
Original assignee: Hubei Huaxin Optoelectronics Co ltd
Current assignee: Hubei Huaxin Optoelectronics Co ltd
Priority date: 2019-07-25
Filing date: 2019-10-17
Publication date: 2025-02-21
Anticipated expiration: 2039-10-17
Also published as: CN210835407U; CN110780421A

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

3P ultra-wide angle under-screen fingerprint lens

Technical Field

The invention relates to fingerprint unlocking, in particular to a 3P ultra-wide angle fingerprint lens.

Background

With the development of science and technology, more and more scientific lovers are researching the comprehensive screen. The off-screen fingerprint identification plays a role in assisting the development of a comprehensive screen, and the off-screen fingerprint solution has the advantage of being capable of being hidden. Although all are called off-screen fingerprint identification, the method can be divided into three types according to the technical principle and the implementation method, namely optical type, ultrasonic type and capacitive type. The three under-screen fingerprint identifications are different, and the development conditions at the current stage are different. Due to the advantages of light, such as rapidness, stability, permeability, etc., under-screen fingerprint lenses are more noticed and demanded by the market. Under the goals of light weight, short object distance, good image quality and the like pursued by the mobile phone, the under-screen fingerprint lens also needs to have the characteristics of wide angle, large aperture, small distortion, high contrast, high cost performance and the like.

Disclosure of Invention

The invention aims to solve the technical problem of providing a 3P ultra-wide angle under-screen fingerprint lens which has the characteristics of wide angle, large aperture, small distortion, high contrast and high cost performance.

The technical scheme includes that a first lens, a second lens, a third lens and an infrared filter are sequentially arranged from an object side to an image side along an optical axis, the first lens is a biconcave negative lens, at least one surface is an aspheric surface, the second lens is a biconvex positive lens, at least one surface is an aspheric surface, the third lens is a biconvex positive lens, and at least one surface is an aspheric surface.

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

Preferably, the following relation is also satisfied, 1.0< |f2/f| <5.0, where f is the composite focal length of the system and f2 is the focal length of the second lens.

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

Preferably, the second lens object plane edge tangent angle θ satisfies-18 < θ < -4.

Preferably, P2 (R1) >0, P2 (R2) <0 of the second lens.

Preferably, the lens satisfies CRA <30 °.

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

The invention provides a fingerprint lens under a 3P ultra-wide angle screen, which meets the market development trend, and uses 3 lenses made of plastic materials, has an ultra-large field angle and a large aperture, and simultaneously has good imaging quality, a smaller chief ray incidence angle and high cost performance. Besides large aperture and high cost performance, the 3P structure can also obtain smaller incident angle of principal ray, so that an object image area with short object distance is processed by an optical system and matched with a chip with smaller receiving angle, and the image information is received and converted into image information by a module chip, so that a good imaging effect is still obtained under a certain magnification, and good image quality can be obtained. The high contrast ratio makes fingerprint identification more agile and accurate.

Drawings

The invention is further illustrated by the following examples in conjunction with the accompanying drawings:

FIG. 1 is a schematic diagram of the structure of the present invention;

FIG. 2 is a schematic diagram of the optical operation of the present invention;

FIG. 3 is a field diagram of example 1;

fig. 4 is a distortion chart of example 1;

FIG. 5 is a spherical aberration diagram of example 1;

FIG. 6 is a field diagram of example 2;

fig. 7 is a distortion chart of example 2;

FIG. 8 is a spherical aberration diagram of example 2;

FIG. 9 is a LAYOUT diagram of example 3;

FIG. 10 is a field diagram of example 3;

fig. 11 is a distortion chart of example 3;

FIG. 12 is a spherical aberration diagram of example 3;

FIG. 13 is a LAYOUT diagram of example 4;

FIG. 14 is a field diagram of example 4;

Fig. 15 is a distortion chart of example 4;

FIG. 16 is a spherical aberration diagram of example 4.

Detailed Description

In the embodiment 1, as shown in fig. 1, a first lens P1, a second lens P2, a third lens P3 and an infrared filter IR are sequentially arranged from an object side to an image side along an optical axis, wherein the first lens P1 is a biconcave negative lens, at least one surface is an aspheric surface, the second lens P2 is a biconvex positive lens, at least one surface is an aspheric surface, and the third lens P3 is a biconvex positive lens, at least one surface is an aspheric surface.

Preferably, an aperture stop is provided between the first lens P1 and the second lens P2.

Preferably, the following relation is also satisfied, 1.0< |f2/f| <5.0, where f is the combined focal length of the system and f2 is the focal length of the second lens P2.

Preferably, the first lens P1, the second lens P2 and the third lens P3 are plastic lenses.

Preferably, the second lens P2 has an object-side edge tangential angle θ satisfying-18 < θP2R1< -4.

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

Preferably, the lens satisfies CRA <30 °. CRA is defined as the angle of incidence of the chief ray to the image plane at the horizontal plane.

Preferably, the first lens P1, the second lens P2 and the third lens P3 are all made of plastic lenses, and more preferably, EP series, ZEONEX series and APEL series can be used as the resin materials. Because such materials have the following advantages over glass materials:

a. The density of the resin lens is 0.83-1.5, and the density of the optical glass is 2.27-5.95.

B. The impact resistance is strong, namely, the impact resistance of the resin lens is generally 8-10 kg/cm ², which is several times that of glass, so that the resin lens is not easy to break, and is safe and durable.

C. The resin lens has good light transmittance, the resin lens has light transmittance close to that of glass in a visible light region, has slightly higher light transmittance than that of glass in an infrared light region, has light transmittance reduced along with the reduction of the wavelength of 0.4um, and almost completely absorbs light with the wavelength of less than 0.3um, so that the ultraviolet light transmittance is poor.

D. The cost is low, the injection molding lens can be mass produced by a precise die, and the cost of a single piece can be greatly reduced.

E. can meet special requirements, such as that the manufacture of the aspherical lens is not difficult, and the manufacture of the glass lens is difficult.

As shown in fig. 2, when the lens is imaged, an object forms an inverted real image on the image plane through the optical system. And then the inverted real image is captured out through post-processing into an electronic signal image to obtain a normal upright image.

In this embodiment, the parameters of the lens are shown in table one,

List one

The tangential angle θ of P2R1 (P2R 1) is shown in Table II,

Watch II

In this embodiment, a first lens P1, a second lens P2, a third lens P3 and an infrared filter IR are sequentially disposed from an object side to an image side along an optical axis, wherein the first lens P1 is a biconcave negative lens, at least one surface is an aspheric surface, the second lens P2 is a biconvex positive lens, at least one surface is an aspheric surface, the third lens P3 is a biconvex positive lens, and at least one surface is an aspheric surface. The first lens, the second lens and the third lens are made of plastic.

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

In this case data, |f2/f|= 2.4044, and 1.0< |f2/f| <5.0.

-11< Theta P2R1< -4.35, and-18 < theta P2R1< -4.

P2 (R1) =11.38, p2 (R2) = -0.4474, P2 (R1) >0, P2 (R2) <0 for the second lens

The case cra=14.90°, dfov= 124.11 °, and ttl= 2.256mm show that the structure has the advantages of small chief ray incidence angle, super-large field angle and short lens length.

The optical distortion curve of this case shows that the distortion value of each field is less than 2%, and the optical distortion value of the peripheral field is between 1% and 2%, so that the TV distortion (optical distortion variation value) is limited in the range of 0-1%, and the distortion is proved to be small, and the embodiment is proved to have high imaging quality.

The spherical aberration curve of the case shows that the spherical aberration is small, the spherical aberration of each point on the curve is within +/-0.05, and the difference between the maximum value and the minimum value is within 0.06, so that the embodiment has the advantages of small aberration and good imaging definition.

As shown in fig. 3, the field curve of example 1 is a field curve, the field curve values of each field of view of S line and T line are smaller than 0.1, and the field curve values of each field of view of S line and T line are smaller than 0.1, which indicates that the field curve is not large in this case and has good uniformity of analysis of the center and the edge.

As shown in fig. 4, the distortion chart of the present embodiment is an optical distortion chart, in which the absolute value of each field distortion value is less than 2%, and the absolute value of the peripheral field distortion value is between 1% and 2%, so that the TV distortion (optical distortion variation value) is limited to the range of 0-1%, and the distortion is small, which proves that the present embodiment has high imaging quality.

As shown in fig. 5, the spherical aberration diagram of example 1 is shown, the spherical aberration curve is a spherical aberration curve, the spherical aberration value of each point on the curve is within ±0.04, and the maximum value to the minimum value is within 0.06, which proves that the spherical aberration is small, so that the example has good imaging definition with small aberration.

In example 2, the structural composition of the lens is the same as that of example 1, the parameters of the lens are shown in table three,

Watch III

The P2R1 tangential angle θ (P2R 1) is shown in table four,

Table four

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

In this case data, |f2/f|= 2.4094, and 1.0< |f2/f| <5.0.

-17.57< Theta P2R1< -4.81, and-18 < theta P2R1< -4.

P2 (R1) =29.16, p2 (R2) = -0.4451, P2 (R1) >0, P2 (R2) <0 for the second lens

The case cra=16.75°, dfov= 123.37 °, and ttl=2.212 mm show that the structure has the advantages of small chief ray incidence angle, super-large field angle and short lens length.

The optical distortion curve of the case shows that the absolute value of each view field distortion value is smaller than 2%, and the absolute value of the peripheral view field optical distortion value is between 1% and 2%, so that the TV distortion (optical distortion change value) is restrained within the range of 0-1%, the distortion is proved to be small, and the embodiment is proved to have high imaging quality.

As shown in fig. 6, a field diagram of example 2 is shown. The curve is a field curvature curve, the field curvature value of each field of the S line and the T line is smaller than 0.1, and the difference value of the field curvature value of each field of the S line and the T line is smaller than 0.1, which indicates that the field curvature of the case is not large, the uniformity of analysis of the center and the edge is good, and especially the field curvature value of the S line close to the S line of the vertical axis is close to 0, which almost has no field curvature and shows good uniformity.

As shown in fig. 7, a distortion chart of example 2 is shown. The curve is an optical distortion curve, the absolute value of each view field distortion value is smaller than 2%, and the absolute value of the peripheral view field optical distortion value is between 1% and 2%, so that the TV distortion (optical distortion change value) is restrained within the range of 0-1%, the distortion is proved to be small, and the embodiment is proved to have high imaging quality.

As shown in fig. 8, the spherical aberration diagram of example 2 is shown. The curve is a spherical aberration curve, the spherical aberration value of each point on the curve is within +/-0.04, and the difference between the maximum value and the minimum value is within 0.06, so that the spherical aberration is small, and the embodiment is proved to have small aberration and good imaging definition.

Example 3 is a negative example, and the positive example condition (1. The aperture is arranged between P1 and P2; 2. The second lens is a biconvex positive lens, at least one aspheric surface, and 3. 1.0< |f2/f| < 5.0) CRA >30 DEG is satisfied.

In this embodiment, the parameters of the lens are shown in table five,

TABLE five

The P2R1 tangential angle θ (P2R 1) is shown in table six,

TABLE six

In this embodiment, a first lens P1, a second lens P2, a third lens P3 and an infrared filter IR are sequentially disposed from an object side to an image side along an optical axis, wherein the first lens P1 is a biconcave negative lens, at least one surface is an aspheric surface, the second lens P2 is a crescent positive lens with a convex object side and a concave object side, at least one surface is an aspheric surface, the third lens P3 is a biconvex positive lens, and at least one surface is an aspheric surface. The first lens, the second lens and the third lens are made of plastic.

An aperture stop is arranged between the second lens P2 and the third lens P3

In this case data, |f2/f|= 3.5285, and 1.0< |f2/f| <5.0.

15.1< Theta P2R1<18.3, and the angle theta of the tangential line angle of the edge of the object surface of the second lens P2 is not satisfied to be-18 < theta P2R1< -4.

P2 (R1) =0.55, P2 (R2) =1.29, P2 (R2) <0 not satisfying the second lens

The case cra= 33.39 °, dfov=112.63°, and ttl=1.983 mm indicates that the structure cannot have a small chief ray incidence angle and an oversized view angle.

The optical distortion curve of the case shows that the maximum field distortion value is 2.2% and the distortion value requirement less than 2% cannot be met.

The spherical aberration curve of the case shows that the spherical aberration is small, the spherical aberration of each point on the curve is within +/-0.02, and the difference from the maximum value to the minimum value is within 0.05, so that the embodiment has the advantages of small aberration and good imaging definition.

As shown in fig. 9, in the LAYOUT chart of embodiment 3, a first lens P1, a second lens P2, a third lens P3 and an infrared filter IR are sequentially disposed from the object side to the image side along the optical axis, wherein the first lens P1 is a biconcave negative lens, the second lens P2 is a biconvex positive lens with a convex object-side image-side concave crescent shape, the third lens P3 is a biconvex positive lens, and an aperture stop is disposed between the second lens P2 and the third lens P3.

As shown in fig. 10, a field diagram of example 3 is shown. The curve is a field curvature curve, the field curvature value of each field of the S line and the T line is smaller than 0.1, and the difference value of the field curvature value of each field of the S line and the T line is smaller than 0.1, which indicates that the field curvature of the case is not large, the uniformity of analysis of the center and the edge is good, and especially the field curvature value of the S line close to the S line of the vertical axis is close to 0, which almost has no field curvature and shows good uniformity.

As shown in fig. 11, a distortion chart of example 3 is shown. The curve is an optical distortion curve, the maximum field distortion value is 2.2%, and the distortion value is larger.

As shown in fig. 12, the spherical aberration diagram of example 3 is a spherical aberration curve, the spherical aberration value of each point on the curve is within ±0.02, and the maximum value to the minimum value is within 0.05, which proves that the spherical aberration is small, so that the example has good imaging definition with small aberration.

Example 4 is a negative example, and the positive example condition (1. The aperture is arranged between P1 and P2; 2. The second lens is a biconvex positive lens, at least one aspheric surface, and 3. 1.0< |f2/f| < 5.0) CRA >30 DEG is satisfied.

In this embodiment, the parameters of the lens are shown in table seven,

Watch seven

The P2R1 tangential angle theta (P2R 1) is shown in table eight,

An aperture stop is arranged between the second lens P2 and the third lens P3

In the case data, |f2/f|= 5.1959.0 < |f2/f| <5.0 is not satisfied.

12.59< Theta P2R1<16.62, and-18 < theta P2R1< -4 > not satisfying the tangential angle theta of the object plane edge of the second lens P2.

P2 (R1) =0.7, P2 (R2) =1.32, P2 (R2) <0 not satisfying the second lens

In this case cra=36.32°, dfov= 121.83 °, and ttl= 2.136mm, which indicates that the structure cannot have a small chief ray incidence angle.

The optical distortion curve of the case shows that the maximum field distortion value is 2.5%, and the distortion value requirement of less than 2% cannot be met.

As shown in fig. 13, in the LAYOUT chart of embodiment 4, a first lens P1, a second lens P2, a third lens P3 and an infrared filter IR are sequentially disposed from the object side to the image side along the optical axis, wherein the first lens P1 is a biconcave negative lens, the second lens P2 is a biconvex positive lens with a convex object-side image-side concave crescent shape, the third lens P3 is a biconvex positive lens, and an aperture stop is disposed between the second lens P2 and the third lens P3.

As shown in fig. 14, a field diagram of example 4 is shown. The curve is a field curve, the field curve value of each field of view of the S line and the T line is smaller than 0.1, and the difference value of the field curve value of each field of view of the S line and the T line is smaller than 0.1, which indicates that the field curve is not large in this case, and the analysis uniformity of the center and the edge is good.

As shown in fig. 15, a distortion chart of example 4 is shown. The curve is an optical distortion curve, the maximum field distortion value is 2.5% and the distortion value is larger.

As shown in fig. 16, the spherical aberration diagram of example 4 is shown. The curve is a spherical aberration curve, the spherical aberration value of each point on the curve is within +/-0.05, but the difference between the maximum value and the minimum value exceeds 0.06, so that the embodiment is proved to have larger aberration and more blurred imaging.

Because of the characteristics of the invention, a total of 3 plastic lenses are used, wherein a "-, +" lens group structure is adopted, an aperture (STO) is arranged between a first lens (P1) and a second lens (P2), the second lens P2 is a biconvex positive lens, and the aspherical plastic lens is produced in a large quantity by using an aspherical mold manufacturing technology, so that the cost is reduced, and a better assembly process is obtained, so that the lens has the advantages of wide angle, large aperture, small distortion, high contrast, high cost performance and the like.

The above embodiments are only preferred embodiments of the present invention, and should not be construed as limiting the present invention, and the scope of the present invention should be defined by the claims, including the equivalents of the technical features in the claims. I.e., equivalent replacement modifications within the scope of this invention are also within the scope of the invention.

Claims

1. A3P ultra-wide angle under-screen fingerprint lens is characterized in that a first lens (P1), a second lens (P2), a third lens (P3) and an infrared filter (IR) are sequentially arranged from an object side to an image side along an optical axis, the first lens (P1) is a biconcave negative lens, at least one surface is an aspheric surface, the second lens (P2) is a biconvex positive lens, at least one surface is an aspheric surface, the third lens (P3) is a biconvex positive lens, at least one surface is an aspheric surface, an aperture (STO) is arranged between the first lens (P1) and the second lens (P2), the following relational expression is also satisfied, 1.0< |f2/f| <5.0, wherein f is a synthetic focal length of a system, f2 is a focal length of the second lens (P2), an edge tangential angle theta of the object side of the second lens (P2) satisfies-18 DEG theta < -4 DEG, the satisfaction is satisfied, the first lens (P1), the second lens (P2) is a plastic material of the third lens (P2), and the third lens (P2) is a plastic material.