CN215494318U - Fingerprint lens under big image plane LCD screen of infrared microspur super wide angle - Google Patents

Abstract

The utility model relates to an infrared macro ultra-wide angle large image surface LCD screen lower fingerprint lens, wherein an optical system of the lens comprises a front group lens A, a diaphragm C, a rear group lens B, a parallel flat plate and an IMA image surface which are sequentially arranged along a light path direction, the front group lens A comprises a meniscus negative lens, and the rear group lens B is sequentially provided with a first biconvex lens and a second biconvex lens along an incident light path; the front mirror surface and the rear mirror surface of the negative meniscus lens, the first biconvex lens and the second biconvex lens are aspheric surfaces; the air space between the negative meniscus lens and the first biconvex lens is 0.4 mm-0.5 mm, and the air space between the first biconvex lens and the second biconvex lens is 0.2 mm-0.3 mm. The lens has the characteristics of large field angle, low distortion and low focal length, can perform corresponding fingerprint identification work in an infrared band, and solves the problems that the existing low-cost LCD screen cannot reach the brightness of an OLED screen, so that effective projection cannot be performed, and fingerprints on the screen cannot be identified.

Description

Fingerprint lens under big image plane LCD screen of infrared microspur super wide angle

Technical Field

The utility model relates to the field of lenses, in particular to an infrared macro wide-angle large-image-plane LCD (liquid crystal display) lower fingerprint lens.

Background

Due to the popularization of the high-end intelligent machine, the application of fingerprint unlocking under the screen is more and more extensive, and the requirement of people on the fingerprint unlocking lens is more and more high. However, the existing under-screen fingerprint unlocking application adopts an under-screen fingerprint module system with an OLED screen matched with visible light. Most of the smart phones at the middle and low ends adopt LCD screens, and the mobile phones with the LCD screens cannot adopt an underscreen fingerprint unlocking system because the light transmission of the LCD screens is poor.

SUMMERY OF THE UTILITY MODEL

In view of the above, the present invention is to provide an infrared macro ultra-wide angle large image plane LCD lower fingerprint lens with a large field angle, low distortion and low focal length, which can perform fingerprint identification in the infrared band.

The utility model is realized by adopting the following scheme: an optical system of the lens comprises a front group lens A, a diaphragm C, a rear group lens B, a parallel flat plate and an IMA image surface which are sequentially arranged along the direction of a light path, wherein the front group lens A comprises a meniscus negative lens, and the rear group lens B is sequentially provided with a first biconvex lens and a second biconvex lens along the incident light path; the front mirror surface and the rear mirror surface of the negative meniscus lens, the first biconvex lens and the second biconvex lens are aspheric surfaces; the air space between the negative meniscus lens and the first biconvex lens is 0.4 mm-0.5 mm, and the air space between the first biconvex lens and the second biconvex lens is 0.2 mm-0.3 mm.

Further, the total focal length f of the optical system, the focal length f1 of the negative meniscus lens, the focal length f2 of the first biconvex lens, and the focal length f3 of the second biconvex lens satisfy the following relationships: -0.7< f1/f2< -0.5, 2.0< f2/f <2.3, 1.8< f3/f < 2.1.

Further, the thicknesses of the negative meniscus lens, the first biconvex lens and the second biconvex lens are 0.913mm, 0.879mm and 0.514mm, respectively.

Furthermore, the meniscus negative lens, the first biconvex lens and the second biconvex lens are all made of EP 5000.

Compared with the prior art, the utility model has the following beneficial effects: the fingerprint lens under the infrared microspur super-wide-angle large-image-surface LCD screen has the characteristics of large field angle, low distortion and low focal length, can perform corresponding fingerprint identification work in an infrared band, and solves the problems that the existing low-cost LCD screen cannot reach the brightness of an OLED screen, so that effective projection cannot be performed, and fingerprints on the screen cannot be identified.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to specific embodiments and accompanying drawings.

Drawings

FIG. 1 is a schematic diagram of an optical system of a lens barrel according to the present invention;

FIG. 2 is a schematic diagram of MTF values of the lens of the present invention;

FIG. 3 is a schematic view of the curvature of field and optical distortion of the lens of the present invention;

the reference numbers in the figures illustrate: 100-front group lens A; 110-negative meniscus lens; 200-rear group lens B; 210-a first biconvex lens; 220-a second biconvex lens; 300-a diaphragm; 400-parallel plates; 500-IMA image plane.

Detailed Description

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

As shown in fig. 1 to 3, an optical system of the lens includes a front group lens a, a diaphragm C, a rear group lens B, a parallel flat plate and an IMA image plane, which are sequentially arranged along a light path direction, wherein the front group lens a includes a meniscus negative lens, and the rear group lens B is sequentially provided with a first biconvex lens and a second biconvex lens along an incident light path; the front mirror surface and the rear mirror surface of the negative meniscus lens, the first biconvex lens and the second biconvex lens are aspheric surfaces; the air space between the negative meniscus lens and the first biconvex lens is 0.4mm to 0.5mm, preferably 0.49mm, the air space between the first biconvex lens and the second biconvex lens is 0.2mm to 0.3mm, preferably 0.28mm, and the air space between the second biconvex lens and the parallel flat plate is 0.211 mm.

When light enters, a light path sequentially enters the front group of lenses A, the diaphragm C, the rear group of lenses B and the parallel flat plate, and finally imaging is carried out on an IMA image surface; the first biconvex lens and the second biconvex lens of the rear group lens B are made of high-refractive-index materials, and when light passes through, secondary aberration and distortion can be corrected, so that the lens system can be well corrected through reasonable collocation of the surface types.

The lens effectively solves the problems that the existing low-cost LCD screen cannot reach the brightness of an OLED screen, so that effective projection cannot be carried out, and fingerprints on the screen cannot be identified. Only one 940nm infrared LED light source is needed to be matched, and corresponding fingerprint identification work can be carried out in the infrared band. The 940nm wave band is a near-infrared light source and invisible to naked eyes, and the problem that eyes are injured in the bright area of the screen is effectively solved.

In the present embodiment, the total focal length f of the optical system, the focal length f1 of the meniscus negative lens, the focal length f2 of the first biconvex lens, and the focal length f3 of the second biconvex lens satisfy the following relationship: -0.7< f1/f2< -0.5, 2.0< f2/f <2.3, 1.8< f3/f < 2.1.

In the present embodiment, the thicknesses of the negative meniscus lens, the first biconvex lens and the second biconvex lens are 0.913mm, 0.879mm and 0.514mm, respectively.

In this embodiment, the negative meniscus lens, the first biconvex lens and the second biconvex lens are all made of EP 5000.

In this embodiment, the central radius of curvature of the front mirror surface of the negative meniscus lens is-173.635 mm, and the central radius of curvature of the rear mirror surface is 0.644 mm; the central curvature radius of the front mirror surface of the first biconvex lens is 2.286mm, and the central curvature radius of the rear mirror surface is-1.581 mm; the central curvature radius of the front mirror surface of the second biconvex lens is 1.854mm, and the central curvature radius of the rear mirror surface is-1.586 mm. The surface form equation of the aspherical surface is as follows:

wherein z is a distance vector from a vertex of the aspheric surface when the aspheric surface is at a position having a height of R along the optical axis direction, c is a curvature of a paraxial region of the aspheric surface, c =1/R, R is a curvature radius, c is a reciprocal of the curvature radius, k is a conic coefficient, a1 is an aspheric 2 nd order coefficient, a2 is an aspheric 4 th order coefficient, a3 is an aspheric 6 th order coefficient, a4 is an aspheric 8 th order coefficient, a5 is an aspheric 10 th order coefficient, a6 is an aspheric 12 th order coefficient, a7 is an aspheric 14 th order coefficient, and a8 is an aspheric 16 th order coefficient. The aspheric coefficients of the three aspheric lenses of the negative meniscus lens, the first biconvex lens and the second biconvex lens are as follows:

the optical system composed of the lens achieves the following optical indexes:

(1) focal length: EFFL =0.76 mm;

(2) f number = 1.45;

(3) the field angle: 2w is more than or equal to 121 degrees;

(4) the diameter of the imaging circle is larger than phi 2.46;

(5) working spectral range: 930nm to 970 nm;

(6) the total optical length TTL is less than or equal to 4.75mm, and the optical back intercept is more than or equal to 0.9 mm;

(7) F-Tan (theta) distortion = -2%.

Any embodiment disclosed herein above is meant to disclose, unless otherwise indicated, all numerical ranges disclosed as being preferred, and any person skilled in the art would understand that: the preferred ranges are merely those values which are obvious or representative of the technical effect which can be achieved. Since the numerical values are too numerous to be exhaustive, some of the numerical values are disclosed in the present invention to illustrate the technical solutions of the present invention, and the above-mentioned numerical values should not be construed as limiting the scope of the present invention.

If the utility model discloses or relates to parts or structures which are fixedly connected to each other, the fixedly connected parts can be understood as follows, unless otherwise stated: a detachable fixed connection (for example using bolts or screws) is also understood as: non-detachable fixed connections (e.g. riveting, welding), but of course, fixed connections to each other may also be replaced by one-piece structures (e.g. manufactured integrally using a casting process) (unless it is obviously impossible to use an integral forming process).

In addition, terms used in any technical solutions disclosed in the present invention to indicate positional relationships or shapes include approximate, similar or approximate states or shapes unless otherwise stated.

Any part provided by the utility model can be assembled by a plurality of independent components or can be manufactured by an integral forming process.

The foregoing is directed to preferred embodiments of the present invention, other and further embodiments of the utility model may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. However, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention are within the protection scope of the technical solution of the present invention.

Claims (4)

1. The utility model provides a big image plane LCD screen of infrared microspur fingerprint camera lens down which characterized in that: the optical system of the lens comprises a front group lens A, a diaphragm C, a rear group lens B, a parallel flat plate and an IMA image surface which are sequentially arranged along the direction of a light path, wherein the front group lens A comprises a meniscus negative lens, and the rear group lens B is sequentially provided with a first biconvex lens and a second biconvex lens along the incident light path; the front mirror surface and the rear mirror surface of the negative meniscus lens, the first biconvex lens and the second biconvex lens are aspheric surfaces; the air space between the negative meniscus lens and the first biconvex lens is 0.4 mm-0.5 mm, and the air space between the first biconvex lens and the second biconvex lens is 0.2 mm-0.3 mm.

2. The infrared macro ultra-wide-angle large-image-plane LCD screen lower fingerprint lens of claim 1, which is characterized in that: the total focal length f of the optical system, the focal length f1 of the meniscus negative lens, the focal length f2 of the first biconvex lens, and the focal length f3 of the second biconvex lens satisfy the following relationships: -0.7< f1/f2< -0.5, 2.0< f2/f <2.3, 1.8< f3/f < 2.1.

3. The infrared macro ultra-wide-angle large-image-plane LCD screen lower fingerprint lens of claim 1, which is characterized in that: the thicknesses of the negative meniscus lens, the first biconvex lens and the second biconvex lens are respectively 0.913mm, 0.879mm and 0.514 mm.

4. The infrared macro ultra-wide-angle large-image-plane LCD screen lower fingerprint lens of claim 3, which is characterized in that: the meniscus negative lens, the first biconvex lens and the second biconvex lens are all made of EP 5000.

Images