CN209842638U

CN209842638U - Optical type underscreen fingerprint identification module

Info

Publication number: CN209842638U
Application number: CN201920110045.2U
Authority: CN
Inventors: 郎欢标
Original assignee: MIKOLTA OPTOELECTRONIC TECHNOLOGY Co Ltd
Current assignee: MIKOLTA OPTOELECTRONIC TECHNOLOGY Co Ltd
Priority date: 2019-01-22
Filing date: 2019-01-22
Publication date: 2019-12-24
Anticipated expiration: 2029-01-22

Abstract

The utility model discloses an optical underscreen fingerprint identification module, which comprises a display screen, an imaging module and an infrared illumination system which are arranged below the display screen, the infrared illumination system is arranged at the periphery of the imaging module, the imaging module comprises a lens module with a near-infrared single waveband, an aperture diaphragm arranged in the lens module and an image sensor arranged below the lens module, the infrared illumination system comprises a free-form surface light guide lens for light distribution, and more than two near-infrared band light sources arranged below the free-form surface light guide lens, wherein after light emitted by the near-infrared band light sources is distributed by the free-form surface light guide lens, the maximum light distribution angle of the emitted light meets the condition that theta is more than 70 degrees, the evenness of the radiance of the fingerprint surface can reach more than 70 percent by covering the whole fingerprint range for imaging. The resolution of the edge field of view of the imaging module at 80 line pairs is about 0.25, and the distortion of the full field of view is controlled within 2%.

Description

Optical type underscreen fingerprint identification module

Technical Field

The utility model relates to a fingerprint identification module, more specifically say, relate to an optical type screen fingerprint identification module down.

Background

The fingerprint identification module of intelligence in machine realizes the discernment to individual fingerprint characteristic through specific response module. Every current smart mobile phone of money can possess a fingerprint identification module, collects and converts user's fingerprint into data through this module, and the storage lies in the specific area of machine storage, calls when using, and the mode that different fingerprint identification techniques collected the fingerprint also is different.

According to the different modes of collecting fingerprints, the fingerprint identification module is mainly divided into a capacitive fingerprint module, a radio frequency fingerprint module and an optical fingerprint module in the day ahead.

Most of smart phones in the day use a capacitive fingerprint sensor assembly, an electric field is formed by a silicon cell microarray and conductive subcutaneous electrolyte, and the pressure difference between the silicon cell microarray and the conductive subcutaneous electrolyte varies due to the fluctuation of the fingerprint, so that accurate fingerprint measurement can be realized. But the sensor surface is easily damaged by using silicon material, so that the service life is reduced. And a fingerprint image is formed by irregularities between ravines and ridges of a fingerprint, so that it is difficult to recognize a dirty finger, a wet finger, or the like, and the finger discrimination rate is low.

The radio frequency fingerprint module comprises two types of radio wave detection and over-production wave detection at the present stage, the principle is similar to the detection of the yield of seabed substances, and the specific form of the fingerprint is detected by the signal reflection of specific frequency. The radio frequency fingerprint module technology is that a sensor emits a trace radio frequency signal to penetrate through the epidermal layer of a finger to control and measure the texture of the inner layer so as to obtain the best fingerprint image. The fingerprint module has the greatest advantage that a finger does not need to be in contact with the fingerprint module, so that the appearance of the mobile phone is not greatly influenced. The defects are that the resolution ratio of the fingerprints is low and the repeatability is poor.

The optical fingerprint module images the fingerprint of a user by utilizing the refraction and reflection of light rays, and then identifies the fingerprint characteristics by an image identification method, and has the advantages that: the imaging resolution is high, and the image recognition of fingerprint characteristics is easier. And it is very pleasing to the eye and practical, hides in the display screen below, and very secret is difficult to be found, and is integrated with the display screen, its mainly used does not have frame screen design, "the HOME key that disappears" and Touch ID fingerprint sensor of smart mobile phone of next generation.

An optical fingerprint recognition sensor using a pinhole array for image stitching has been proposed by two-star electronics corporation of korea (patent No.: US20180012069a 1). As shown in fig. 1, it can realize the identification of fingerprint features with larger area and shorter thickness. Which divides the fingerprint surface and the sensing surface into corresponding small cells. Each cell is imaged through a small hole in the middle. And then the images are spliced again by an image splicing method. However, it has the following disadvantages:

1. the imaging of each small unit is circular, and after the imaging is carried out on the sensor, 4 sides need to be cut off to change the imaging into a square, so that subsequent image splicing can be carried out.

2. The imaging of each unit on the sensor is reversed by 180 degrees, the images of each unit need to be respectively rotated by 180 degrees and then spliced, and the spliced images are correct images. Finally, the characteristics of the spliced images are identified, and the fingerprint characteristics of the user can be identified.

3. Due to the adoption of the pinhole, most light rays can be blocked, and only a small part of light rays can image the fingerprint features through the pinhole, so that the brightness of an image surface is darker, and the contrast of the image is reduced.

4. Because the imaging of each unit needs to be cut, reversed and spliced respectively, the computation amount is large, and the operation of the image identification characteristics after splicing is added, the process is complex, and the computation speed of the image identification is slow.

5. The system requires the use of a larger area image sensor, the size of which is comparable to the size of the fingerprint surface to be identified, resulting in a relatively high cost of the system.

Moreover, convergent technologies have proposed an underscreen fingerprint recognition system using oblique imaging optics (U.S. Pat. No.: US20180005005A 1). Referring to fig. 2, the optical system includes a prism 6170 and a lens 6210 disposed obliquely. Which is used to image and identify the fingerprint area of the 6150 surface. The method has the advantages that a single imaging light path is adopted, imaging is a single image, complex image cutting, splicing and other processing processes are not needed, image processing is relatively simple, and the operation speed is high; in addition, the thickness of the system is relatively thin.

The disadvantages of this system are also evident: the angle of view θ of the imaging system is also relatively small, the angle between the fingerprint region 6150 and the image sensor 6230 is very large, and the resulting fingerprint image is trapezoidal, although the trapezoidal image can be corrected to be square by deflecting the sensor 6230 at an angle or by placing the lens 6210 off-axis. But results in local distortion, reduced imaging resolution, and a reduction in the modulation transfer function curve.

Disclosure of Invention

In order to overcome the above-mentioned defect among the prior art, the utility model provides an optical type screen fingerprint identification module down.

In order to achieve the above object, the utility model provides an optical type screen fingerprint identification module down, including the display screen, install imaging module and infrared lighting system in the display screen below, infrared lighting system installs in imaging module's periphery, imaging module is wide angle imaging module, the angle of vision that imaging module is used for the formation of image exceeds 110, imaging module includes the lens module, sets up the aperture diaphragm in the lens module, installs the image sensor in lens module below, infrared lighting system is including the free curved surface leaded light lens that is used for the grading and install the light source in the near-infrared wave band more than two of free curved surface leaded light lens below or the light source of visible light wave band.

Preferably, the imaging module is a wide-angle imaging module, the lens module includes a wide-angle concave lens, a first convex lens installed below the wide-angle concave lens, and a second convex lens installed below the first convex lens, the aperture stop is disposed between the wide-angle concave lens and the first convex lens, the image sensor is installed below the second convex lens, the second convex lens is a plano-convex lens, the upper surface of the second convex lens is a convex surface, and the lower surface of the second convex lens is plated with an optical medium film that allows infrared light to pass through and blocks visible light to pass through.

Preferably, the lens module includes a wide-angle concave lens, a first convex lens installed below the wide-angle concave lens, a second convex lens installed below the first convex lens, and a filter installed below the second convex lens and used for transmitting infrared light and blocking visible light, the aperture diaphragm is arranged between the first convex lens and the second convex lens, and the image sensor is installed below the filter.

Preferably, the lens module comprises a wide-angle concave lens, a first convex lens arranged below the wide-angle concave lens, a filter plate arranged below the first convex lens and used for transmitting infrared light and blocking visible light, the aperture diaphragm is arranged between the wide-angle concave lens and the first convex lens, and the image sensor is arranged below the filter plate.

Preferably, the wide-angle concave lens and the first convex lens are aspheric lenses, and the upper surface and the lower surface of the wide-angle concave lens and the upper surface and the lower surface of the first convex lens are both high-order aspheric surfaces.

Preferably, the free-form surface light guide lens of the infrared illumination system is annular, the free-form surface light guide lens includes a light condensing surface located above the light source and used for collecting light emitted by the light source, and a free-form surface used for reflecting incident light, the bottom end of the free-form surface is connected with the light condensing surface and inclines from the outer lower part to the inner upper part, and the top end of the free-form surface is connected with a light emitting surface.

Preferably, the light emitting surface is a horizontal surface, the light collecting surface is a convex surface for collecting light emitted by the light source, and the free curved surface is a continuous total reflection light distribution curved surface or a mixture of a plurality of free curved surfaces.

Preferably, the light exit surface is a horizontal surface, the light collection surface is a fresnel light collection surface, and the free-form surface includes a first sawtooth-shaped total reflection surface that is arranged on an outer side surface of the free-form surface light guide lens and inclines from the outer bottom to the inner top, and a second sawtooth-shaped total reflection surface that is arranged on an inner side surface of the free-form surface light guide lens and inclines from the outer bottom to the inner top.

Preferably, an opaque reflecting block is arranged above the first sawtooth total reflection surface of the free-form surface light guide lens, and the reflecting block and the free-form surface light guide lens are integrally formed.

Preferably, the light exit surface is a horizontal surface, the light collection surface is a convex surface for collecting light emitted by the light source, and the free-form surface includes a continuous total reflection surface that is arranged on an outer side surface of the free-form surface light guide lens and is inclined from an outer lower side to an inner upper side, and a sawtooth-shaped total reflection surface that is arranged on an inner side surface of the free-form surface light guide lens and is inclined from an outer lower side to an inner upper side.

Preferably, the maximum light distribution angle of the light beam emitted from the light beam emitting surface is θ, and θ > 70 °.

Preferably, the free-form surface light guide lens is annular, the free-form surface light guide lens comprises a concave surface which is positioned above the light source and used for expanding light rays emitted by the light source, and a sawtooth-shaped refraction curved surface is arranged above the concave surface.

Preferably, the concave surface is a quadric surface or an ellipsoid.

Preferably, the concave surface is an off-axis ellipsoid, and an included angle of 15 ° to 45 ° is formed between the axis of the off-axis ellipsoid and the central optical axis of the imaging module.

Preferably, the maximum light distribution angle of the light passing through the zigzag refractive curved surface is θ, and θ > 80 °.

Preferably, the top surface of the display screen is provided with a fingerprint surface for contacting a fingerprint, and the conjugate distance between the fingerprint surface and the surface of the image sensor is 3.05mm-7.05 mm.

Preferably, the diameter of the imaging area of the fingerprint surface is larger than 6 mm.

Preferably, the imaging module is a near-infrared single-band imaging lens module or a visible multi-band imaging lens module.

Preferably, the wavelength of the light source in the near infrared band is 750mm to 2000 nm;

preferably, the light source is a light emitting diode LED or a white light emitting diode LED with a visible light band with a wavelength of 430mm to 680 mm.

Preferably, the light source is an infrared light emitting diode (IR LED) or a laser emitting tube. Preferably, the imaging lens module is made of an infrared-transmitting resin material which allows infrared light to transmit therethrough and blocks visible light from transmitting therethrough.

Preferably, the surface of the light-emitting surface of the free-form surface light guide lens is a horizontal surface, a non-horizontal surface, a mixed curved surface with a sawtooth microstructure, a micro-lens array surface, a micro-prism array surface, a free-form surface or a frosted surface with a light mixing characteristic.

Preferably, the display screen is an OLED display screen.

Compared with the prior art, the beneficial effects of the utility model reside in that:

the utility model discloses a display screen installs imaging module and infrared lighting system in the display screen below, infrared lighting system installs in imaging module's periphery, imaging module is wide angle imaging module, the angle of view that imaging module is used for the formation of image exceeds 110, imaging module includes the lens module, sets up the aperture diaphragm in the lens module, installs the image sensor in lens module below, infrared lighting system is including the free curved surface leaded light lens that is used for the grading and install the light source more than two in free curved surface leaded light lens below. The maximum light distribution angle of the emitted light meets the condition that theta is larger than 70 degrees so as to cover the whole fingerprint range for imaging, the radiation degree uniformity of the fingerprint surface can reach more than 70 percent, and the uniform illumination of the fingerprint surface can be met, so that the auxiliary imaging module can accurately and clearly image the fingerprint characteristics. The resolution of the edge field of view of the imaging module at 80 line pairs is about 0.25, and the distortion of the full field of view is controlled within 2%.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a structural view of an optical fingerprint recognition sensor using a pinhole array for image stitching, which is proposed by samsung electronics of korea, patent No. US20180012069a 1;

FIG. 2 is a block diagram of an underscreen fingerprint recognition system using tilted imaging optics, U.S. Pat. No. US20180005005A1, issued to convergent science and technology corporation;

fig. 3 is a cross-sectional view of an optical underscreen fingerprint identification module according to an embodiment of the present invention;

fig. 4 is an isometric side exploded view of an optical underscreen fingerprint recognition module according to an embodiment of the present invention;

fig. 5 is an imaging schematic diagram of an imaging module of an optical underscreen fingerprint identification module according to an embodiment of the present invention;

fig. 6 is a light path diagram of an imaging module of an optical underscreen fingerprint identification module according to an embodiment of the present invention;

fig. 7 is a modulation transfer function diagram of an imaging module of an optical underscreen fingerprint identification module according to an embodiment of the present invention;

fig. 8 is a field curvature and distortion diagram of an imaging module of an optical underscreen fingerprint identification module according to an embodiment of the present invention;

fig. 9 is an isometric view of a free-form surface light guide lens of an optical underscreen fingerprint identification module according to an embodiment of the present invention;

fig. 10 is a top view of a free-form surface light guide lens of an optical underscreen fingerprint identification module according to an embodiment of the present invention;

fig. 11 is a bottom view of a free-form surface light guide lens of an optical underscreen fingerprint identification module according to an embodiment of the present invention;

fig. 12 is a light distribution diagram of an infrared illumination system of an optical underscreen fingerprint identification module according to an embodiment of the present invention;

fig. 13 is a computer simulation diagram of an infrared illumination system of an optical underscreen fingerprint identification module according to an embodiment of the present invention;

fig. 14A is a diagram illustrating a simulation result of radiation distribution of a fingerprint surface of an optical underscreen fingerprint identification module according to an embodiment of the present invention;

fig. 14B is a second simulation result diagram of radiation distribution of the fingerprint surface of the optical underscreen fingerprint identification module according to the first embodiment of the present invention;

fig. 14C is a second simulation result diagram of radiation distribution of the fingerprint surface of the optical underscreen fingerprint identification module according to the first embodiment of the present invention;

fig. 14D is a fourth graph showing the simulation result of the radiation distribution of the fingerprint surface of the optical underscreen fingerprint identification module according to the first embodiment of the present invention;

fig. 15 is a cross-sectional view of an optical underscreen fingerprint identification module according to a second embodiment of the present invention;

FIG. 16 is an enlarged view of portion A of FIG. 15;

fig. 17 is a light distribution diagram of an infrared illumination system of an optical underscreen fingerprint identification module according to a second embodiment of the present invention;

fig. 18 is a cross-sectional view of an optical underscreen fingerprint identification module according to a third embodiment of the present invention;

fig. 19 is a cross-sectional view of an optical underscreen fingerprint identification module according to a fourth embodiment of the present invention;

FIG. 20 is an enlarged view of portion B of FIG. 19;

fig. 21 is a light distribution diagram of an infrared illumination system of an optical underscreen fingerprint identification module according to a fourth embodiment of the present invention;

fig. 22 is a cross-sectional view of an optical underscreen fingerprint identification module according to a fifth embodiment of the present invention;

fig. 23 is a light distribution diagram of an infrared illumination system of an optical underscreen fingerprint identification module according to a fifth embodiment of the present invention;

fig. 24 is a cross-sectional view of an optical underscreen fingerprint identification module according to a sixth embodiment of the present invention;

fig. 25 is a light distribution diagram of an infrared illumination system of an optical underscreen fingerprint identification module according to a sixth embodiment of the present invention;

fig. 26 is a light path diagram of an imaging module of an optical underscreen fingerprint identification module according to a seventh embodiment of the present invention;

fig. 27 is an optical path diagram of an imaging module of an optical underscreen fingerprint identification module according to an eighth embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by a person skilled in the art without creative efforts shall be covered by the protection scope of the present invention.

An embodiment of the utility model provides an optical type screen fingerprint identification module down.

Example one

Please refer to fig. 3-6, the utility model provides an optical type is fingerprint identification module under screen, including OLED display screen 110, install imaging module, the infrared lighting system in OLED display screen 110 below, cladding in lens cone 130 in the lens module outside, the infrared lighting system is installed in the periphery of lens cone 130, imaging module includes the lens module, sets up aperture diaphragm 150 in the lens module, installs image sensor 180 in lens module below, the infrared lighting system is including being used for the free curved surface leaded light lens 120 of grading and installing in the light source 190 more than two of free curved surface leaded light lens 120 below, the light source is infrared emitting diode IR LED or laser emission pipe, adopts infrared emitting diode IRLED in this embodiment. Referring to fig. 9-11, the free-form light guide lens 120 has a first flange 124 and a second flange 125 at the sides for mounting and positioning the free-form light guide lens 120, and the light exit surface 123 at the top of the free-form light guide lens 120 further has a spacer 126 for supporting the upper panel. In this embodiment, three infrared light emitting diodes IR LEDs 190 with a wavelength of 940nm are adopted, and the three infrared light emitting diodes IR LEDs 190 are uniformly distributed around the imaging module. The imaging module is a wide-angle imaging system, the field angle of the imaging module is greater than 110 degrees, the field angle of the imaging module of the specific embodiment is 130 degrees, the object plane of the imaging module is a fingerprint plane located above the OLED display screen 110, and the image plane of the imaging module is an image sensor 180 surface.

The imaging module is an imaging lens module with a single near-infrared band or an imaging lens module with multiple visible light bands.

The wavelength of the light source in the near-infrared band is a band of 750mm to 2000nm, and the wavelength of the light source in the near-infrared band adopted in this embodiment is 1000 mm.

In addition, the light source can also select a light source with a wavelength of 430 mm-680 mm in a visible light wave band, such as a light emitting diode LED or a white light emitting diode LED.

The imaging lens module is made of an infrared-transmitting resin material which allows infrared light to transmit and blocks visible light from transmitting, such as infrared-transmitting PC, PE, K26p, and the like.

The lens module includes a wide-angle concave lens 140, a first convex lens 160 disposed below the wide-angle concave lens 140, and a second convex lens 170 disposed below the first convex lens 160, the aperture stop 150 is disposed between the wide-angle concave lens 140 and the first convex lens 160, the image sensor 180 is disposed below the second convex lens 170, the second convex lens 170 is a plano-convex lens, an upper surface 171 of the second convex lens 170 is a convex surface, and a lower surface 172 of the second convex lens 170 is plated with an optical dielectric film that allows infrared light to transmit and blocks visible light to transmit.

The wide-angle concave lens 140 and the first convex lens 160 are aspheric lenses, and the upper surface 141 and the lower surface 142 of the wide-angle concave lens 140 and the upper surface 161 and the lower surface 162 of the first convex lens 160 are high-order aspheric surfaces.

The wide-angle concave lens 140 is made of a material with low refractive index and high dispersion coefficient; the first convex lens 160 and the second convex lens 170 are made of a material with a high refractive index and a low dispersion coefficient.

The imaging mode of the imaging module is as follows: the fingerprint features on the surface of the OLED display screen 110 pass through the wide-angle concave lens 140, the aperture stop 150, the first convex lens 160, and the second convex lens 170 and then enter the image sensor 180 for imaging. The fingerprint characteristics of the surface of the OLED display screen 110 and the sensing surface of the image sensor 180 are object-image conjugate surfaces.

The conjugate distance (total optical length) between the fingerprint surface 111 and the surface of the image sensor 180 is 3.05mm to 7.05mm, and the total optical length is preferably 4.5mm in the present embodiment 1.

The area of the fingerprint surface above the OLED display screen 110 for imaging is larger than 6mm in diameter, and the imaging area of the fingerprint surface in this embodiment 1 is preferably 8mm in diameter.

The imaging principle of the imaging module from the fingerprint surface 111 to the image sensor 180 is shown in fig. 5, the light path diagram of the imaging module from the fingerprint surface 111 to the image sensor 180 is shown in fig. 6, and the modulation transfer function of the design result of the imaging module is shown in fig. 7, wherein the resolution of the middle field of view is about 0.78 at 80 line pairs, and the resolution of the edge field of view is about 0.255 at 80 line pairs. The field curvature and distortion are shown in fig. 8, and the distortion of the full field of view is controlled within 2%.

Table 1 shows the optical system parameters of the imaging module in this embodiment.

TABLE 1

Table 2 shows aspheric coefficients of the upper surface 141 and the lower surface 142 of the wide-angle concave lens 140, and the upper surface 161 and the lower surface 162 of the first convex lens 160 of the imaging module.

TABLE 2

The free-form surface light guide lens is annular, the free-form surface light guide lens 120 surrounds the imaging module, the free-form surface light guide lens 120 comprises a light condensing surface 121 located above the light source 190 and used for collecting light rays emitted by the light source 190 and a free-form surface 122 used for reflecting incident light rays, the bottom end of the free-form surface 122 is connected with the light condensing surface 121 and inclines upwards from the outer lower part to the inner lower part, and the top end of the free-form surface 122 is connected with a light emitting surface 123.

Referring to fig. 12, the light exit surface 123 is a horizontal surface, and the light-condensing surface 121 is a convex surface. The light-emitting surface 123 of the free-form surface light guide lens can also be a non-horizontal surface, a mixed curved surface with a sawtooth microstructure, a micro-lens array surface, a micro-prism array surface, a free-form surface or a frosted surface with light mixing characteristics.

The light emitted by the light source 190 is collected and converged by the light-converging surface 121, the converged light is collimated upwards and incident on the free-form surface 122, the free-form surface 122 is a continuous total reflection light distribution curved surface, the free-form surface 122 turns and distributes light to the incident light, the light distributed by the free-form surface 122 is totally reflected, and the light is emitted at a large inclination angle after being emitted from the light-emitting surface above the free-form surface 122 and uniformly illuminates fingerprints on the upper surface of the OLED display screen. An included angle between the light emitted from the light emitting surface 123 and the optical axis Z1Z2 is a light distribution angle θ, and the maximum light distribution angle is 110 °, which satisfies θ > 70 °, so as to cover the entire fingerprint range for imaging. The finger illuminated by the infrared light of the infrared illumination system is reflected downwards by the reflected light with the fingerprint characteristics, and the reflected light enters the imaging module at the middle position for imaging and identifying the image characteristics.

The 3D image file of the infrared illumination module is input into photometric analysis software for computer simulation, and the ray tracing is shown in fig. 13. The results of the illumination simulation of the fingerprint surface are shown in FIGS. 14A/14B/14C/14D. Here, the observation screen is arranged at a position close to the fingerprint surface 111 above the OLED display screen 110, and the simulation result shows that the radiance uniformity of the fingerprint surface 111 can reach more than 80%. The infrared illumination system can uniformly illuminate the fingerprint surface 11, so that the auxiliary imaging module can accurately and clearly image the fingerprint characteristics.

Example two

Please refer to fig. 15 and 16, the utility model provides an optical type is fingerprint identification module under screen, including OLED display screen 210, install imaging module, the infrared lighting system in OLED display screen 210 below, cladding in lens barrel 230 outside the lens module, the infrared lighting system is installed in the periphery of lens barrel 230, imaging module includes the lens module, sets up aperture diaphragm 250 in the lens module, installs the image sensor 280 in lens module below, the infrared lighting system is including the free curved surface leaded light lens 220 that is used for the grading and install two or more light sources 290 in free curved surface leaded light lens 220 below.

The difference between the second embodiment and the first embodiment is that: the light exit surface 224 of the free-form surface light guide lens 220 is a horizontal surface, the light collection surface 221 is a fresnel light collection surface, and the free-form surface includes a first sawtooth-shaped total reflection surface 222 arranged on the outer side surface of the free-form surface light guide lens and inclined from the outside to the inside and the top, and a second sawtooth-shaped total reflection surface 223 arranged on the inner side surface of the free-form surface light guide lens and inclined from the outside to the inside and the top.

The light distribution mode of the infrared illumination module is shown in fig. 17. The light-gathering surface 221 below the free-form surface light guide lens 220 with a large inclination angle for light distribution and close to the LED is a fresnel surface, and is used for collecting and converging light rays emitted by the light source 290, and the converged light rays are collimated upwards and incident on the free-form surface 222. The free-form surface 222 is a sawtooth-shaped total reflection light distribution curved surface, that is, it is formed by mixing a plurality of free-form surfaces, and the free-form surface 222 is used for turning incident light and distributing light, and the light distributed by total reflection is totally incident on a sawtooth-shaped total reflection surface 223 located below the inner side of the free-form surface light guide lens 220. The incident light is reflected again and distributed by the sawtooth-shaped total reflection surface 223, and then is emitted by the upper emission surface 224 at a large inclination angle, so as to uniformly illuminate the fingerprint on the upper surface of the OLED display screen 210. The light exiting the exit face 224 has a maximum light distribution angle greater than 70 to cover the entire range of the fingerprint used for imaging.

The finger illuminated by the light from the light source 290 of the infrared illumination system is reflected downward with the reflected light of the fingerprint feature, and the reflected light enters the imaging module located at the middle position for imaging and identification of the image feature.

The imaging module is a wide-angle imaging module, the lens module includes a wide-angle concave lens 240, a first convex lens 260 installed below the wide-angle concave lens 240, and a second convex lens 270 installed below the first convex lens 260, the aperture stop 250 is disposed between the wide-angle concave lens 240 and the first convex lens 260, the image sensor 280 is installed below the second convex lens 270, the second convex lens 270 is a plano-convex lens, the upper surface of the second convex lens 270 is a convex surface, and the lower surface of the second convex lens 270 is plated with an optical medium film which allows infrared light to transmit and blocks visible light to transmit.

EXAMPLE III

Please refer to fig. 18, the utility model provides an optical type is fingerprint identification module under screen, including OLED display screen 310, install imaging module, the infrared lighting system in OLED display screen 310 below, cladding in lens module outside lens cone 330, the infrared lighting system is installed in lens cone 330's periphery, imaging module includes the lens module, sets up aperture stop 350 in the lens module, installs the image sensor 380 in lens module below, the infrared lighting system is including the free form surface leaded light lens 320 that is used for the grading and install two or more light sources 390 in free form surface leaded light lens 320 below.

The difference between the third embodiment and the second embodiment is that: an opaque reflecting block 320-b is further disposed above the free-form surface light guide lens 320, and the reflecting block 320-b is used for collecting light leaking from the first sawtooth reflecting surface 322 and reflecting all light emitted from the light source 390 onto a second sawtooth total reflecting surface 323 located below the inner side of the free-form surface light guide lens 320. The second sawtooth-shaped total reflection 323 reflects the incident light again and distributes the light, and the light is emitted at a large inclination angle after being emitted through the light emitting surface 323 above, so that the light is uniformly emitted to the fingerprint on the upper surface of the OLED display screen 310. The light exiting from the light exit surface 323 has a maximum light distribution angle greater than 70 ° to cover the entire range of the fingerprint used for imaging.

In this embodiment, a double-material or double-color molding method is adopted, and the material of the opaque reflecting block 320-b and the material of the transparent free-form surface light guide lens 320 are molded by injection.

The lens module includes a wide-angle concave lens 340, a first convex lens 360 installed below the wide-angle concave lens 340, and a second convex lens 370 installed below the first convex lens 360, the aperture stop 350 is disposed between the wide-angle concave lens 340 and the first convex lens 360, the image sensor 380 is installed below the second convex lens 370, the second convex lens 370 is a plano-convex lens, the upper surface of the second convex lens 370 is a convex surface, and the lower surface of the second convex lens 370 is plated with an optical medium film allowing infrared light to transmit and blocking visible light to transmit

In the second embodiment, compared with the second embodiment, since all the light beams are emitted toward the center of the optical axis Z1Z2 and distributed, the light intensity distribution is stronger at the middle position of the fingerprint surface directly above the imaging module. And the light intensity distribution is slightly weakened at a position close to the periphery.

Example four

Please refer to fig. 19 and 20, the utility model provides an optical type is fingerprint identification module under screen, including OLED display screen 410, install imaging module, the infrared lighting system in OLED display screen 410 below, cladding in lens cone 430 outside the lens module, the infrared lighting system is installed in lens cone 430's periphery, imaging module includes the lens module, sets up aperture stop 450 in the lens module, installs image sensor 480 in lens module below, the infrared lighting system is including being used for the free form surface leaded light lens 420 of grading and installing two or more light sources 490 in free form surface leaded light lens 420 below.

The difference between the fourth embodiment and the first embodiment is that: the free-form surface includes a continuous total reflection surface 422 inclined from the outer lower side to the inner upper side provided on the outer side surface of the free-form surface light guide lens 420 and a jagged total reflection surface 423 inclined from the outer lower side to the inner upper side provided on the inner side surface of the free-form surface light guide lens 420.

Fig. 21 shows a light distribution pattern of the infrared illumination module. In the free-form surface light guide lens 420 with the large inclination angle for light distribution, a light-gathering surface 421 below the free-form surface light guide lens 420 and close to the light source 490 is a convex surface, the light-gathering surface 421 is used for collecting and converging light rays emitted by the light source 490, and the converged light rays are upwards collimated and incident on the continuous total reflection surface 422 above the light-gathering surface. The continuous total reflection surface 422 is a total reflection light distribution curved surface, the continuous total reflection surface 422 is used for turning and distributing incident light, and the light which is subjected to total reflection light distribution by the continuous total reflection surface 422 is totally incident on a sawtooth-shaped total reflection surface 423 positioned below the inner side of the free-form surface light guide lens 420. The sawtooth-shaped total reflection surface 423 reflects and distributes incident light again, and the incident light is emitted through the light emitting surface 424 above the sawtooth-shaped total reflection surface and finally emitted at a large inclination angle, so that fingerprints on the upper surface of the OLED display screen 410 are uniformly illuminated. The maximum light distribution angle θ of the light emitted from the light emitting surface 424 is > 70 ° to cover the entire range of the fingerprint for imaging.

The finger illuminated by the infrared light of the infrared illumination system is reflected downwards by the reflected light with the fingerprint characteristics, and the reflected light enters the imaging module at the middle position for imaging and identifying the image characteristics.

The imaging module is a wide-angle imaging module, an angle of view of the imaging module for imaging is greater than 110 °, the lens module includes a wide-angle concave lens 440, a first convex lens 460 installed below the wide-angle concave lens 440, and a second convex lens 470 installed below the first convex lens 460, the aperture stop 450 is disposed between the wide-angle concave lens 440 and the first convex lens 460, the image sensor 480 is installed below the second convex lens 470, the second convex lens 470 is a plano-convex lens, an upper surface of the second convex lens 470 is a convex surface, and an optical medium film allowing infrared light to transmit and blocking visible light to transmit is plated on a lower surface of the second convex lens 470.

EXAMPLE five

Please refer to fig. 22, the utility model provides an optical type is fingerprint identification module under screen, including OLED display screen 510, install imaging module, infrared lighting system in OLED display screen 510 below, cladding in lens barrel 530 in the lens module outside, infrared lighting system installs in the periphery of lens barrel 530, imaging module is wide angle imaging module, imaging module includes the lens module, sets up aperture diaphragm 550 in the lens module, installs the image sensor 580 in lens module below, infrared lighting system is including the free-form surface leaded light lens 520 that is used for the grading and install the light source 590 more than two below free-form surface leaded light lens 520.

The difference between the fifth embodiment and the first embodiment is that: the free-form surface light guide lens 520 comprises a concave surface 521 located above the light source 590 and used for expanding light emitted by the light source 590, a sawtooth-shaped refraction curved surface 522 is arranged above the concave surface 521, and the concave surface 521 is a quadric surface or an elliptical surface. In this embodiment, the shape of the concave surface 521 is preferably an elliptical surface, referring to fig. 23, the concave surface 521 first expands the infrared light emitted from the light source 590, and the expanded light passes through the upper zigzag refractive curved surface 522 to perform a second expansion and distribution of light, and finally emits the light at a large inclination angle, so as to form a substantially uniform radiance distribution on the fingerprint surface above the OLED display 510. The light rays distributed from the zigzag refractive curved surface 522 have a maximum light distribution angle theta > 0 deg. so as to cover the whole range of the fingerprint for imaging.

The imaging module is a wide-angle imaging module, an angle of view of the imaging module for imaging exceeds 110 °, the imaging module includes a wide-angle concave lens 540, a first convex lens 560 installed below the wide-angle concave lens 540, and a second convex lens 570 installed below the first convex lens 560, the aperture stop 550 is disposed between the wide-angle concave lens 540 and the first convex lens 560, the image sensor 580 is installed below the second convex lens 570, the second convex lens 570 is a plano-convex lens, an upper surface of the second convex lens 570 is a convex surface, and an optical dielectric film allowing infrared light to transmit and blocking visible light to transmit is plated on a lower surface of the second convex lens 570.

EXAMPLE six

Please refer to fig. 24, the utility model provides an optical type is fingerprint identification module under screen, including OLED display screen 610, install imaging module, the infrared lighting system in OLED display screen 610 below, cladding in lens module outside lens cone 630, the infrared lighting system is installed in the periphery of lens cone 630, imaging module includes the lens module, sets up aperture diaphragm 650 in the lens module, installs image sensor 680 in lens module below, the infrared lighting system is including the free form light guide lens 520 that is used for the grading and install in two or more light sources 690 of free form light guide lens 620 below.

The difference between the sixth embodiment and the fifth embodiment is that: the concave surface 621 is an off-axis ellipsoid, an included angle of 15-45 degrees is formed between the axis of the off-axis ellipsoid and the central optical axis Z1Z2 of the imaging module, and the axis of the off-axis ellipsoid is off-axis 30 degrees inward in the embodiment. Referring to fig. 25, the concave surface 621 deflects infrared light emitted by the LED590, most of the deflected infrared light is deflected toward the inner axis Z1Z2, the deflected infrared light is expanded and distributed by the upper zigzag refractive curved surface 622, and finally emitted at a large inclination angle, so as to form a substantially uniform radiance distribution on the fingerprint surface above the OLED display 610. The light rays distributed by the zigzag-shaped refraction curved surface 622 have the maximum light distribution angle theta larger than 70 degrees so as to cover the whole fingerprint range for imaging.

The imaging module is a wide-angle imaging module, the field angle that the imaging module is used for imaging exceeds 110 °, the imaging module includes a wide-angle concave lens 640, a first convex lens 660 installed below the wide-angle concave lens 640, a second convex lens 670 installed below the first convex lens 660, the aperture stop 650 is disposed between the wide-angle concave lens 640 and the first convex lens 660, the image sensor 680 is installed below the second convex lens 670, the second convex lens 670 is a plano-convex lens, the upper surface of the second convex lens 670 is a convex surface, and the lower surface of the second convex lens 670 is plated with an optical medium film that allows infrared light to transmit and blocks visible light to transmit.

EXAMPLE seven

Please refer to fig. 26, the utility model provides an optical type screen is fingerprint identification module down, including OLED display screen 710, install imaging module, the infrared lighting system in OLED display screen 710 below, cladding lens cone 730 in the lens module outside, the infrared lighting system is installed in the periphery of lens cone 730, imaging module includes the lens module, sets up aperture diaphragm 750 in the lens module, installs the image sensor 780 in lens module below, the infrared lighting system is including the free form leaded light lens 720 that is used for the grading and install the light source 790 more than two in free form leaded light lens 720 below.

The seventh embodiment differs from the first embodiment in that: the lens module includes a wide-angle concave lens 740, a first convex lens 750 installed below the wide-angle concave lens 740, a second convex lens 770 installed below the first convex lens 750, and a filter 780 installed below the second convex lens 770 and used for transmitting infrared light and blocking visible light, wherein the aperture stop 760 is disposed between the first convex lens 750 and the second convex lens 770, and the image sensor 790 is installed below the filter 780.

The imaging module is a wide-angle imaging lens, the field angle of the imaging module is greater than 110 degrees, the field angle of the imaging module in this embodiment is 130 degrees, the object plane of the imaging module is a fingerprint plane located on the OLED display screen 710, and the image plane of the imaging module is the surface of the image sensor 790.

The conjugate distance (total optical length) between the fingerprint surface and the surface of the image sensor is 3.05mm-7.05mm, and the total optical length is 4.8mm in the embodiment.

The area of the fingerprint surface above the OLED display screen 710 for imaging is larger than 6mm in diameter, and the imaging area of the fingerprint surface in this embodiment is 8mm in diameter.

Example eight

Please refer to fig. 27, the utility model provides an optical type is fingerprint identification module under screen, including OLED display screen 810, install imaging module, the infrared lighting system in OLED display screen 810 below, cladding lens cone 830 in the lens module outside, the infrared lighting system is installed in the periphery of lens cone 830, imaging module includes the lens module, sets up aperture diaphragm 850 in the lens module, installs the image sensor 880 in lens module below, the infrared lighting system is including the free form light guide lens 820 that is used for the grading and install two or more light sources 890 in free form light guide lens 820 below.

The difference between the eighth embodiment and the first embodiment is that: the lens module includes a wide-angle concave lens 840, a first convex lens 860 disposed below the wide-angle concave lens 840, and a filter 870 disposed below the first convex lens 860 for transmitting infrared light and blocking visible light, the aperture stop 850 is disposed between the wide-angle concave lens 840 and the first convex lens 860, and the image sensor 880 is disposed below the filter 870.

The imaging module is a wide-angle imaging lens, the field angle of the imaging module is greater than 110 degrees, the field angle of the imaging module in this embodiment is 130 degrees, the object plane of the imaging module is a fingerprint plane located above the OLED display screen 810, and the image plane of the imaging module is the surface of the image sensor 880.

The conjugate distance (total optical length) between the fingerprint surface and the surface of the image sensor 880 is 3.05mm-7.05mm, and the total optical length is 3.97718mm in this embodiment.

The area of the fingerprint surface above the OLED display screen 810 for imaging is larger than 6mm in diameter, and the imaging area of the fingerprint surface in this embodiment is about 7mm in diameter.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention should be equivalent replacement modes, and all are included in the scope of the present invention.

Claims

1. The utility model provides an optical type fingerprint identification module under screen which characterized in that: the imaging module comprises a lens module with a single near-infrared waveband, an aperture diaphragm arranged in the lens module, and an image sensor arranged below the lens module, wherein the imaging module comprises a free-form surface light guide lens for light distribution and light sources arranged in more than two near-infrared wavebands below the free-form surface light guide lens or light sources arranged in visible waveband.

2. The optical underscreen fingerprint recognition module of claim 1, wherein: the imaging module is wide-angle imaging module, imaging module includes wide-angle concave lens, installs in the first convex lens of wide-angle concave lens below, installs in the second convex lens of first convex lens below, the aperture diaphragm sets up between wide-angle concave lens and first convex lens, image sensor installs in second convex lens below, the second convex lens is plano-convex lens, the upper surface of second convex lens is the convex surface, the lower surface of second convex lens is plated and is allowed the infrared light to see through, blocks the optical medium membrane that visible light saw through.

3. The optical underscreen fingerprint recognition module of claim 1, wherein: the lens module comprises a wide-angle concave lens, a first convex lens arranged below the wide-angle concave lens, a second convex lens arranged below the first convex lens, a filter plate arranged below the second convex lens and used for transmitting infrared light and blocking visible light, an aperture diaphragm is arranged between the first convex lens and the second convex lens, and the image sensor is arranged below the filter plate.

4. The optical underscreen fingerprint recognition module of claim 1, wherein: the lens module comprises a wide-angle concave lens, a first convex lens arranged below the wide-angle concave lens, and a filter arranged below the first convex lens and used for transmitting infrared light and blocking visible light, wherein the aperture diaphragm is arranged between the wide-angle concave lens and the first convex lens, and the image sensor is arranged below the filter.

5. The optical underscreen fingerprint recognition module of any one of claims 2-4, wherein: imaging module's wide angle concave lens and first convex lens are the aspheric surface lens, the upper surface and the lower surface of wide angle concave lens and first convex lens are the high order aspheric surface.

6. The optical underscreen fingerprint recognition module of claim 5, wherein: the free-form surface light guide lens comprises a light gathering surface and a free-form surface, wherein the light gathering surface is positioned above the light source and used for collecting light rays emitted by the light source, the free-form surface is used for reflecting incident light rays, the bottom end of the free-form surface is connected with the light gathering surface and inclines upwards from the outside to the inside, and the top end of the free-form surface is connected with a light emitting surface.

7. The optical underscreen fingerprint recognition module of claim 6, wherein: the light emergent surface is a horizontal plane, the light condensing surface is a convex surface used for collecting light emitted by the light source, and the free curved surface is a continuous total reflection light distribution curved surface or a mixture of a plurality of free curved surfaces.

8. The optical underscreen fingerprint recognition module of claim 6, wherein: the free-form surface comprises a first sawtooth-shaped total reflection surface and a second sawtooth-shaped total reflection surface, the first sawtooth-shaped total reflection surface is arranged on the outer side surface of the free-form surface light guide lens, the first sawtooth-shaped total reflection surface inclines from the outer lower side to the inner upper side, the second sawtooth-shaped total reflection surface is arranged on the inner side surface of the free-form surface light guide lens, and the second sawtooth-shaped total reflection surface inclines from the outer lower side to the inner.

9. The optical underscreen fingerprint recognition module of claim 8, wherein: an opaque reflecting block is arranged above the first sawtooth total reflection surface of the free-form surface light guide lens.

10. The optical underscreen fingerprint recognition module of claim 9, wherein: the reflecting block and the free-form surface light guide lens are integrally formed through double-material or double-color injection molding.

11. The optical underscreen fingerprint recognition module of claim 6, wherein: the free-form surface comprises a continuous total reflection surface which is arranged on the outer side surface of the free-form surface light guide lens and inclines from the outer lower part to the inner upper part, and a sawtooth-shaped total reflection surface which is arranged on the inner side surface of the free-form surface light guide lens and inclines from the outer lower part to the inner upper part.

12. An optical underscreen fingerprint recognition module according to any one of claims 6-11, wherein: in the infrared illumination system, the maximum light distribution angle of the light emitted from the light emitting surface is theta which is larger than 70 degrees.

13. An optical underscreen fingerprint recognition module according to any one of claims 6-11, wherein: the top surface of the display screen is provided with a fingerprint surface for contacting a fingerprint, and the conjugate distance between the fingerprint surface and the surface of the image sensor is 3.0mm-7.0 mm.

14. The optical underscreen fingerprint recognition module of claim 13, wherein: the diameter of the imaging area of the fingerprint surface is more than 6 mm.

15. The optical underscreen fingerprint recognition module of claim 5, wherein: the appearance of the free-form surface light guide lens of the infrared illumination system is annular, the free-form surface light guide lens comprises a concave surface which is positioned above the infrared light source and used for expanding the beam of light emitted by the infrared light source, and a sawtooth-shaped refraction curved surface is arranged above the concave surface.

16. The optical underscreen fingerprint recognition module of claim 15, wherein: the concave surface of the free-form surface light guide lens is a quadric surface or an elliptical surface.

17. The optical underscreen fingerprint recognition module of claim 15, wherein: the concave surface of the free-form surface light guide lens is an off-axis ellipsoid, and an included angle of 15-45 degrees is formed between the axis of the off-axis ellipsoid and the central optical axis of the imaging module.

18. An optical underscreen fingerprint recognition module according to any one of claims 15-17, wherein: the maximum light distribution angle of the light rays of the free-form surface light guide lens passing through the sawtooth-shaped refraction curved surface is theta, and theta is larger than 70 degrees.

19. An optical underscreen fingerprint recognition module according to any one of claims 15-17, wherein: the top surface of the display screen is provided with a fingerprint surface for contacting a fingerprint, and the conjugate distance between the fingerprint surface and the surface of the image sensor is 3.05mm-7.05 mm.

20. The optical underscreen fingerprint recognition module of claim 19, wherein: the diameter of the imaging area of the fingerprint surface is more than 6 mm.

21. The optical underscreen fingerprint recognition module of claim 1, wherein: the imaging module is an imaging lens module with a single near-infrared band or an imaging lens module with multiple visible light bands.

22. The optical underscreen fingerprint recognition module of claim 1, wherein: the wavelength of the light source of the near infrared band is 750 mm-2000 nm.

23. The optical underscreen fingerprint recognition module of claim 1, wherein: the light source is an infrared light emitting diode (IR LED) or an infrared laser emission tube.

24. The optical underscreen fingerprint recognition module of claim 21, wherein: the imaging lens module is made of an infrared-transmitting resin material which allows infrared light to transmit and blocks visible light from transmitting.

25. The optical underscreen fingerprint recognition module of claim 1, wherein: the surface of the light emitting surface of the free-form surface light guide lens is a horizontal surface, a non-horizontal surface, a mixed curved surface with a sawtooth microstructure, a micro-lens array surface, a micro-prism array surface, a free-form surface or a frosted surface with light mixing characteristics.

26. The optical underscreen fingerprint recognition module of claim 1, wherein: the light source is a light emitting diode LED or a white light emitting diode LED with the wavelength of 430 mm-680 mm in a visible light wave band.