CN212160210U

CN212160210U - Lens system, detection module and optical detection device

Info

Publication number: CN212160210U
Application number: CN202020120042.XU
Authority: CN
Inventors: 肖业卫
Original assignee: Shenzhen Fushi Technology Co Ltd
Current assignee: Shenzhen Fushi Technology Co Ltd
Priority date: 2019-12-25
Filing date: 2020-01-19
Publication date: 2020-12-15
Anticipated expiration: 2030-01-19

Abstract

The utility model discloses a lens system, it includes the first lens that has negative focal power, has positive focal power second lens and has the third lens of positive focal power that arrange in proper order along the optical axis from the thing side to picture side. The first lens, the second lens and the third lens respectively comprise a pair of aspheric optical areas close to the object side and the image side, the optical axis of the lens system sequentially passes through the central point of each optical area, and the surface rise and the half aperture of each optical area have preset variation ranges. The utility model also provides a detect module and optical detection device.

Description

Lens system, detection module and optical detection device

Technical Field

The utility model relates to the field of photoelectric technology, especially, relate to a lens system, and use detection module, optical detection device and electronic equipment of this lens system.

Background

With the technical progress and the improvement of living standard of people, users demand more functions and fashionable appearance for electronic products such as mobile phones, tablet computers, cameras and the like. At present, the development trend of electronic products such as mobile phones and the like is to have a higher screen occupation ratio and have fingerprint detection or other biological characteristic detection functions. In order to improve the screen occupation ratio to realize a full screen or a nearly full screen effect, the lens module is required to be arranged below the screen of the electronic product so as to perform the biological characteristic detection under the screen in an imaging mode. However, because the electronic products generally have the design requirements of miniaturization and thinness, the space under the screen is very limited, and the existing lens module can not meet the requirements in terms of size and optical function.

SUMMERY OF THE UTILITY MODEL

In view of this, the utility model provides a can improve lens system, detection module, optical detection device and electronic equipment of prior art problem.

One aspect of the present invention is to provide a lens system, including a first lens having negative refractive power, a second lens having positive refractive power, and a third lens having positive refractive power, which are sequentially arranged along an optical axis from an object side to an image side;

the first lens comprises a first surface close to an object side and a second surface close to an image side, the first surface and the second surface respectively comprise a first optical area and a second optical area which are used for deflecting light rays for imaging, and the first optical area and the second optical area are both aspheric surfaces in central symmetry shapes and respectively provided with a first central point and a second central point;

the second lens comprises a third surface close to the object side and a fourth surface close to the image side, the third surface and the fourth surface respectively comprise a third optical area and a fourth optical area which are used for deflecting light rays for imaging, and the third optical area and the fourth optical area are both aspheric surfaces in central symmetry shapes and respectively provided with a third central point and a fourth central point; and

the third lens comprises a fifth surface close to the object side and a sixth surface close to the image side, the fifth surface and the sixth surface respectively comprise a fifth optical area and a sixth optical area which are used for deflecting light rays for imaging, and the fifth optical area and the sixth optical area are both aspheric surfaces in central symmetry shapes and respectively provided with a fifth central point and a sixth central point;

the optical axis passes through the first center point to the sixth center point, the first center point to the sixth center line point are respectively taken as original points, the direction from the object side to the image side along the optical axis is the positive direction of the surface vector height, wherein the value range of the surface vector height of the point on the first optical area is-0.019 mm to 0.25mm, the value range of the distance between the point on the first optical area and the optical axis is 0mm to 1.3mm, the value range of the surface vector height of the point on the second optical area is 0mm to 0.5mm, the value range of the distance between the point on the second optical area and the optical axis is 0mm to 0.5mm, the value range of the surface vector height of the point on the third optical area is 0mm to 0.056mm, the range of the distance between the point on the third optical area and the optical axis is 0mm to 0.5mm, and the value range of the surface vector height of the point on the fourth optical area is-0.083 mm to 0mm, the distance between a point on the fourth optical area and the optical axis ranges from 0mm to 0.5mm, the surface rise of a point on the fifth optical area ranges from-0.055 mm to 0.015mm, the distance between a point on the fifth optical area and the optical axis ranges from 0mm to 0.45mm, the surface rise of a point on the sixth optical area ranges from 0mm to 0.55mm, and the distance between a point on the sixth optical area and the optical axis ranges from-0.45 mm to 0 mm.

In some embodiments, on the first optical region, the surface rise corresponding to a point 0.2mm apart from the optical axis is-0.0093 mm, the surface rise corresponding to a point 0.4mm apart from the optical axis is-0.0181 mm, the surface rise corresponding to a point 0.6mm apart from the optical axis is-0.0089 mm, the surface rise corresponding to a point 0.8mm apart from the optical axis is 0.0221mm, the surface rise corresponding to a point 1.0mm apart from the optical axis is 0.0785mm, and the surface rise corresponding to a point 1.2mm apart from the optical axis is 0.1944 mm.

In some embodiments, on the second optical region, a point on the second optical region at a distance of 0.2mm from the optical axis corresponds to a surface rise of 0.0508mm, and a point at a distance of 0.4mm from the optical axis corresponds to a surface rise of 0.2562 mm.

In some embodiments, in the third optical region, a surface rise corresponding to a point at a distance of 0.1mm from the optical axis is 0.0055mm, a surface rise corresponding to a point at a distance of 0.2mm from the optical axis is 0.0210mm, a surface rise corresponding to a point at a distance of 0.3mm from the optical axis is 0.0416mm, and a surface rise corresponding to a point at a distance of 0.4mm from the optical axis is 0.0528 mm.

In some embodiments, on the fourth optical zone, the surface rise corresponding to a point 0.1mm apart from the optical axis is-0.0031 mm, the surface rise corresponding to a point 0.2mm apart from the optical axis is-0.0136 mm, the surface rise corresponding to a point 0.3mm apart from the optical axis is-0.0357 mm, and the surface rise corresponding to a point 0.4mm apart from the optical axis is-0.0793 mm.

In some embodiments, in the fifth optical region, the surface rise corresponding to a point at a distance of 0.1mm from the optical axis is 0.0036mm, the surface rise corresponding to a point at a distance of 0.2mm from the optical axis is 0.0110mm, the surface rise corresponding to a point at a distance of 0.3mm from the optical axis is 0.0104mm, and the surface rise corresponding to a point at a distance of 0.4mm from the optical axis is-0.0531 mm.

In some embodiments, in the sixth optical region, the surface rise corresponding to a point 0.1mm apart from the optical axis is-0.0107 mm, the surface rise corresponding to a point 0.2mm apart from the optical axis is-0.0427 mm, the surface rise corresponding to a point 0.3mm apart from the optical axis is-0.0972 mm, the surface rise corresponding to a point 0.4mm apart from the optical axis is-0.1852 mm, and the surface rise corresponding to a point 0.5mm apart from the optical axis is-0.3794.

In some embodiments, the thickness of the first lens along the optical axis varies from 0.22mm to 0.27mm, the effective focal length of the first lens varies from-0.5 mm to-0.7 mm, the thickness of the second lens along the optical axis varies from 0.42mm to 0.46mm, the effective focal length of the second lens varies from 0.8mm to 1.2mm, the thickness of the third lens along the optical axis varies from 0.40mm to 0.45mm, and the effective focal length of the third lens varies from 0.6mm to 1.0 mm.

In some embodiments, a distance between the second center point and the third center point along the optical axis ranges from 0.48mm to 0.52mm, and a distance between the fourth center point and the fifth center point along the optical axis ranges from 0.19mm to 0.25 mm.

In some embodiments, the optical distortion of the lens system is less than 4%, the effective focal length of the lens system ranges from 0.20mm to 0.50mm, the F-number of the lens system is less than 1.3, and the field angle of the lens system is greater than 125 degrees.

The utility model discloses an aspect one kind detects module, it includes as preceding arbitrary embodiment the lens system and set up in the image sensor of image side of lens system, image sensor includes the light sensing face, the light sensing face is used for receiving the warp light signal after the transmission of lens system converts the signal of telecommunication into corresponding in order to realize detecting, the light sensing face does the imaging surface of lens system.

In some embodiments, a distance between the sixth central point and the light sensing surface along the optical axis ranges from 0.6mm to 0.7mm, and a distance between the first central point of the first lens and the light sensing surface along the optical axis ranges from 2mm to 3 mm.

In some embodiments, the maximum image height imaged on the light sensing surface varies from 1.0mm to 1.5 mm.

An aspect of the utility model provides an optical detection device, it includes:

the protective layer comprises an upper surface and a lower surface which are oppositely arranged, and the upper surface is used for being directly touched by an external object during detection;

the display module is positioned below the lower surface and used for displaying pictures through the protective layer; and

the detection module according to any one of the preceding embodiments, which is located below the lower surface, is configured to receive a detection beam returned by an external object to image a portion of the external object touching the upper surface.

In some embodiments, the upper surface of the protective layer is an object plane of the lens system, and a distance between the upper surface of the protective layer and the first center point along the optical axis ranges from 2.3mm to 2.8 mm.

In some embodiments, the lens system has a predetermined field angle range, an area of the upper surface of the protective layer within the field angle range is defined as a field area, the field area has a field center, the optical axis of the lens system passes through the field center, and the distance between a point on the boundary of the field area and the field center varies from 3mm to 5 mm.

In some embodiments, the display module includes a bottom surface facing the detection module, a variation range of a distance between the bottom surface of the display module and the first center point along the optical axis is 0.8mm to 1.2mm, and a variation range of a distance between the bottom surface of the display module and the light sensing surface along the optical axis direction is 3mm to 4 mm.

The beneficial effects of the utility model reside in that, the light emitting area edge of luminous chip aligns each other with the nearest top edge of circuit board distance protective layer lower surface, makes the light emitting area of luminous chip can be close to furthest the lower surface emission measuring beam of protective layer, in order to reduce the energy loss of measuring beam in the projection process.

Drawings

Fig. 1 is a schematic front plan view illustrating an optical detection device applied to an electronic device according to an embodiment of the present invention;

FIG. 2 is a schematic partial cross-sectional view of the optical detection device of FIG. 1 taken along line II-II;

FIG. 3 is a schematic structural diagram of an embodiment of the display module shown in FIG. 2;

FIG. 4 is a schematic structural diagram of another embodiment of the display module shown in FIG. 2;

FIG. 5 is a schematic diagram of an embodiment of the optical inspection device of FIG. 2;

FIG. 6 is a schematic diagram of another embodiment of the optical inspection device of FIG. 2;

FIG. 7 is a schematic diagram of an imaging optical path of a lens system of the detection module shown in FIG. 2;

FIG. 8 is a cross-sectional view of the first lens of FIG. 7 taken through a plane passing through the optical axis;

FIG. 9 is a cross-sectional view of the second lens of FIG. 7 taken through a plane passing through the optical axis;

FIG. 10 is a cross-sectional view of the third lens of FIG. 7 taken through a plane passing through the optical axis;

FIG. 11 is a graph of the optical transfer function of the lens system of FIG. 7 as a function of the spatial frequency of the sample fringes;

FIG. 12 is a graph of optical transfer function versus image height dimension for the lens system depicted in FIG. 7;

FIG. 13 is an optical distortion diagram of the lens system of FIG. 7;

fig. 14 is an astigmatic field curvature diagram of the lens system illustrated in fig. 7.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

In the detailed description of the embodiments of the invention, it will be understood that when a substrate, a sheet, a layer, or a pattern is referred to as being "on" or "under" another substrate, another sheet, another layer, or another pattern, it can be "directly" or "indirectly" on the other substrate, the other sheet, the other layer, or the other pattern, or one or more intervening layers may also be present. The thickness and size of each layer in the drawings of the specification may be exaggerated, omitted, or schematically represented for clarity. Further, the sizes of the elements in the drawings do not completely reflect actual sizes.

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

The following disclosure provides many different embodiments, or examples, for implementing different features of the invention. In order to simplify the disclosure of the present invention, the components and settings of the specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. Furthermore, the present invention may repeat reference numerals and/or reference letters in the various examples, which are repeated for purposes of simplicity and clarity and do not in themselves dictate a relationship between the various embodiments and/or configurations discussed. In addition, the present disclosure provides examples of various specific processes and materials, but one of ordinary skill in the art may recognize applications of other processes and/or use of other materials.

Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention may be practiced without one or more of the specific details, or with other structures, components, and so forth. In other instances, well-known structures or operations are not shown or described in detail to avoid obscuring aspects of the invention.

Referring to fig. 1 to fig. 2, fig. 1 is a schematic front plan view illustrating an optical detection device 10 applied to an electronic apparatus 1 according to an embodiment of the present invention. FIG. 2 is a schematic partial cross-sectional view of the optical detection device 10 of FIG. 1 taken along line II-II. The optical detection device 10 is used for detecting the biological characteristics of an external object 1000. The optical inspection device 10 has a length direction along the Y-axis, a width direction along the X-axis, and a thickness direction along the Z-axis. The optical detection device 10 has a central axis 113 parallel to the longitudinal direction Y, and the optical detection device 10 is substantially axisymmetric with respect to the central axis 113. Optionally, the line II-II is a central axis 113 of the optical detection apparatus 10 or a parallel line located on the central axis 113. The electronic device 1 has a shape corresponding to the optical detection apparatus 10, and accordingly has a length direction along the Y-axis, a width direction along the X-axis, and a thickness direction along the Z-axis. The electronic device 1 comprises a top part 13 and a bottom part 14 which are oppositely arranged along the length direction Y of the electronic device. In some embodiments, the electronic device 1 is, for example, a mobile phone, which may include an earphone 130, a front camera 132, and a sound sensor 140. The earpiece 130 and the front camera 132 may be positioned near the top 13 of the electronic device 1. The sound sensor 140, for example: a microphone may be disposed on the electronic device 1 proximate the base 14.

The optical detection device 10 comprises a display screen 12. The display screen 12 includes a protection layer 100 and a display module 104 sequentially arranged from top to bottom.

The protective layer 100 includes a non-transparent region 210 and a transparent region 220 that are contiguous. The non-transparent area 210 is located around the transparent area 220. The periphery of the transparent area 220 refers to an area other than the edge of one or more sides of the transparent area 220. The transparent region 220 is capable of transmitting visible light and invisible light. The non-transparent region 210 is capable of blocking visible light so that elements inside the display screen 12 are not visible to a user in the non-transparent region 210. The protective layer 100 includes an upper surface 101 and a lower surface 102 disposed opposite each other. The upper surface 101 includes an upper surface of the transparent region 220 and an upper surface of the non-transparent region 210. The lower surface 102 includes a lower surface of the transparent region 220 and a lower surface of the non-transparent region 210.

Illustratively, the main body of the protective layer 100 may be made of a transparent material, such as, but not limited to, transparent glass, a transparent polymer material, or any other transparent material. The protective layer 100 may have a single-layer structure or a multi-layer structure. The protective layer 100 is a substantially thin plate having a predetermined length, width and thickness. The protective layer 100 has a length direction along the Y-axis, a width direction along the X-axis, and a thickness direction along the Z-axis.

Optionally, in some embodiments, the protective layer 100 may include a transparent substrate 103 and an optical film layer 107. The transparent substrate 103 is capable of transmitting visible light and non-visible light, and is a main body portion of the protective layer 100. The optical film layer 107 is disposed on the lower surface 102 of the non-transparent region 210 of the protection layer 100, and the non-transparent region 210 of the protection layer 100 blocks visible light through the optical film layer 107. The non-transparent region 210 of the protection layer 100 includes the optical film layer 107 and a portion of the transparent substrate 103 facing the optical film layer 107. The transparent region 220 of the protection layer 100 includes a portion of the transparent substrate 103 where the optical film layer 107 is not disposed. The transparent substrate 103 is, for example, but not limited to, glass, plastic, resin, or any other transparent material. The optical film layer 107 is a material capable of absorbing visible light.

Optionally, in some embodiments, the optical film layer 107 may be omitted or integrated in the transparent substrate 103.

It is understood that the protective layer 100 may include a plastic film, a tempered film, or other films attached by a user during actual use, and the upper surface 101 of the protective layer 100 is a surface that the external object 1000 directly contacts when performing biometric detection. The upper surface 101 may be an outermost surface of the optical detection device 10, or the upper surface 101 may be an outermost surface of an electronic apparatus 1 comprising the optical detection device 10. In the present application, for example and without limitation, the external object 1000 may be a finger and the biometric detection may be fingerprint detection or fingerprint feature detection.

The display module 104 is located below the lower surface 102 of the protection layer 100, and can emit visible light through the protection layer 100 to realize a display function, such as but not limited to displaying images or characters. The protection layer 100 is used for protecting the display module 104 from the external environment.

Optionally, in some embodiments, the display module 104 is an active light emitting display module, such as but not limited to an organic light emitting diode display module (OLED display module). As shown in fig. 3, the display module 104 includes a first electrode layer 1041, an organic light emitting layer 1042, a second electrode layer 1043, a reflective layer 1044, and a substrate 1045 stacked in sequence from top to bottom, wherein the first electrode layer 1041 is located on a side of the display module 104 facing the protection layer 100. The organic light emitting layer 1042 emits visible light for display under the control of electric signals applied by the first electrode layer 1041 and the second electrode layer 1043. The visible light emitted upward from the organic light emitting layer 1042 is transmitted through the first electrode layer 1041 and the protection layer 100 to display a picture. The visible light emitted downward from the organic light emitting layer 1042 is reflected by the reflective layer 1044 and then sequentially passes through the second electrode layer 1043, the organic light emitting layer 1042, the first electrode layer 1041 and the protective layer 100, and then can also be used for displaying a picture. The display module 104 is located below the passivation layer 100 and substantially opposite to the transparent region 220, and the visible light emitted from the organic light emitting layer 1042 is emitted from the transparent region 220 of the passivation layer 100 to be seen by a user. It can be understood that, by selecting the substrate 1045 with different hardness, the organic light emitting display module 104 may be a rigid display screen that cannot be bent, or may be a flexible display screen that can be bent.

Optionally, in some embodiments, the display module 104 is a passive light emitting display module, such as but not limited to a liquid crystal display module (LCD display module) or an electronic paper display module. As shown in fig. 4, the display module 104 includes, for example, a display panel 105 and a backlight unit 106, the display panel 105 is located below the protection layer 100, and the backlight unit 106 is located below the display panel 105. The backlight unit 106 is used for providing visible light to the display panel 105. The backlight unit 106 may include a reflective sheet (not shown), a light guide plate (not shown), and an optical film set (not shown) stacked in this order from top to bottom. The backlight unit 106 may further include a backlight (not shown) disposed adjacent to one side of the light guide plate. The backlight is used for emitting visible light, and the visible light enters the light guide plate from the side of the light guide plate adjacent to the backlight, is transmitted by the light guide plate, and then is emitted to the display panel 105 through the optical film set. The reflector plate is used for reflecting the visible light emitted from the bottom surface of the light guide plate back to the inside of the light guide plate so as to improve the utilization rate of the visible light. The optical film set is used to diffuse and/or brighten the visible light emitted from the light guide plate and provide the visible light to the display panel 105. The optical film set may include one or more diffusion sheets and/or brightness enhancement films.

The display panel 105 is located below the protection layer 100 and substantially opposite to the transparent area 220, the display panel 105 realizes a function of displaying a picture by modulating the throughput of visible light, and the visible light modulated by the display panel 105 is emitted from the transparent area 220 and is seen by a user through picture contents displayed by the display module 104.

The display panel 105 is, for example but not limited to, a liquid crystal display panel, and may include an array substrate (not shown), a liquid crystal layer (not shown), and a color filter substrate (not shown) sequentially stacked from bottom to top. Accordingly, the optical inspection device 10 is, for example, but not limited to, a liquid crystal optical inspection device or a liquid crystal display. It is understood that the lcd module 104 is generally a rigid display screen that is not bendable.

The optical detection device 10 further includes a detection module 19, and the detection module 19 is located below the display module 104 and is configured to receive the detection light beam 11 returned by the external object 1000 and convert the detection light beam into an electrical signal. Since the detection beam 11 returned through the external object 1000 carries the biometric information of the external object 1000, the biometric information of the external object 1000 can be obtained by analyzing the electrical signal converted from the detection beam 11 returned through the external object 1000, and thus can be used for biometric detection and identification of the external object 1000. The biometric information may be any one or more of, but not limited to, skin texture information such as fingerprints and palm prints, living body information such as blood oxygen, heartbeat, and pulse, depth information, or three-dimensional image information. In the present application, the external object is a finger, and the biometric information to be detected is fingerprint information.

It is understood that if the display module 104 is a passive light emitting display module including a backlight unit 106, the detection module 19 is located below the backlight unit 106, and the detection light beam 11 returned by the external object 1000 needs to pass through the backlight unit 106 and be received by the detection module 19. The detection beam 11 may also be transmitted by the reflective sheet, the light guide plate and the optical film set of the backlight unit 106.

Optionally, in some embodiments, the detection light beam 11 may be emitted by the display module 104. For example, the display module 104 is an OLED display module, the visible light emitted by the OLED display module can be used as the detection light beam 11, and the wavelength range of the detection light beam 11 is, for example, 380 nanometers (nm) to 780 nm.

Optionally, in some embodiments, as shown in fig. 5, the optical detection apparatus 10 may further include a light source module 16, where the light source module 16 is configured to emit a detection light beam 11 to the external object 1000. The detection beam 11 is, for example, but not limited to, near infrared light with a wavelength ranging from 750 nm to 2000 nm, or near infrared light with a wavelength ranging from 800 nm to 2000 nm, or other invisible light that can be used for biometric detection and identification.

Optionally, the light source module 16 may be disposed below the non-transparent region 210 of the protection layer 100 and beside the display module 104. The light source module 16 emits the detection beam 11 to the external object 1000 above the protection layer 100 through the protection layer 100. Optionally, all or part of the detection beam 11 is transmitted through the optical film layer 107 disposed on the non-transparent region 210 when transmitting through the protection layer 100, and the optical film layer 107 is capable of transmitting the detection beam 11 and blocking visible light, such as but not limited to infrared ink capable of transmitting infrared light or near infrared light and blocking visible light. It is understood that in other or modified embodiments, all or part of the detection beam 11 may not pass through the optical film layer 107 when passing through the protection layer 100. For example, the detection light beam 11 emitted by the light source module 16 can be emitted to the external object 1000 through the transparent area 220 of the protection layer 100 via the display module 104. In this case, the optical film layer 107 may have only a function of blocking visible light.

Optionally, as shown in fig. 6, the light source module 16 may also be located below the display module 104 and directly opposite to the transparent area 220 of the protection layer 100. The light source module 16 emits the detection beam 11 to the external object 1000 above the protection layer 100 through the display module 104 and the protection layer 100.

It is understood that, in other or modified embodiments, the light source module 16 may also be disposed at other suitable positions of the optical detection apparatus 10, as long as the light source module 16 can emit the detection light beam 11 to the external object 1000 to achieve detection, and this is not particularly limited in this application.

Alternatively, the detection light beam 11 emitted by the light source module 16 may be directly transmitted through at least the protection layer 100 to be emitted to the external object 1000. Alternatively, the detection light beam 11 emitted by the light source module 16 may be transmitted by a light guide element (not shown) and then emitted to the external object 1000 through at least the protection layer 100. As long as the detection light beam 11 emitted by the light source module 16 can be finally emitted to the external object 1000 to realize detection, this is not specifically limited in this application.

When the detection is performed, the external object 1000 is in contact with the upper surface 101 of the protection layer 100 located at the outermost side, the detection beam 11 is irradiated to the external object 1000 located above the protection layer 100, and the detection beam 11 returned by the external object 1000 passes through the protection layer 100 and the display module 104 and is received by the detection module 19 and converted into a corresponding electric signal to realize the detection.

Optionally, in some embodiments, the manner of returning the detection beam 11 through the external object 1000 includes, but is not limited to, the detection beam 11 entering the inside of the external object 1000 located above the protection layer 100 and then being transmitted out of the surface of the external object 1000 and returning; alternatively, the detection beam 11 propagates by total reflection at least within the protective layer 100 and returns by diffuse reflection at a position where the external object 1000 is in contact with the protective layer 100; alternatively, the detection beam 11 is transmitted through the protective layer 100 and then reflected by the external object 1000 to return. The upper surface 101 of the protective layer 100 has a detection area DA that can be directly touched by the external object 1000 during detection, and the detection light beam 11 returned through the external object 1000 passes through the protective layer 100 from the detection area DA and can return downward to the detection module 19.

Optionally, in some embodiments, as shown in fig. 7, the detection module 19 includes a lens system 190 and an image sensor 196. The lens system 190 is an optical imaging system including a plurality of lenses, the image sensor 196 includes a light sensing surface 198, the light sensing surface 198 is configured to receive light signals transmitted by the lens system 190 and convert the light signals into corresponding electrical signals, and the detection module 19 realizes biometric detection of the external object 1000 by imaging a portion of the external object 1000 in contact with the upper surface 101 of the protective layer 100. Specifically, the detection module 19 images the detection light beam 11 returned by the external object 1000 on the light sensing surface 198 of the image sensor 196 through the lens system 190, the image sensor 196 converts the image of the external object 1000 formed on the light sensing surface 198 into a corresponding electric signal, and the biological characteristic information of the external object 1000 can be acquired by analyzing the image of the external object 1000. For example, the external object 1000 is a finger, and the image of the external object 1000 detected by the detection module 19 is a fingerprint image of a portion of the finger in contact with the upper surface 101 of the protection layer 100.

The lens system 190 has a preset Field Of View (FOV) range, which is a stereo space range facing the object side with the equivalent optical center Of the lens system 190 as a vertex. The field angle range of the lens system 190 is defined as the maximum spatial range in which the lens system 190 can image the external object 1000. The detection light beam 11 returning via the portion of the external object 1000 located within the field angle range can be imaged by the detection module 19 and converted into a corresponding electrical signal for detection.

The field of view of the lens system 190 has a corresponding field of view in a plane passing through the optical axis OA of the lens system 190. It should be noted that, without particular limitation, the field angle of the lens system 190 described in the present application may be a field angle of an XZ plane, a field angle of a YZ plane, or a field angle of another plane or direction. It is understood that the field angles of the lens system 190 in different planes form the field angle range of stereo in space, and the field angle range of the lens system 190 may be at least part of a cone, or other stereo shapes. The area covered by the field angle range of the lens system 190 on different planes is the field area VA of the detection module 19 on the plane, and an object on the plane located in the field area VA can be imaged by the lens system 190 because of being within the field angle range, and thus can be effectively detected by the detection module 19. The area of the upper surface 101 of the protective layer 100 within the field angle range of the lens system 190 is defined as the field area VA of the detection module 19 on the upper surface 101, the area of the upper surface 101 of the protective layer 100 for the external object 1000 to contact during detection is defined as the detection area DA, and the detection area DA includes at least a portion of the field area VA, so that at least a portion of the external object 100 contacting the detection area DA can be detected by the detection module 19. Optionally, in some embodiments, the field area VA is the same as the detection area DA, or the field area VA is smaller than the detection area DA and entirely located within the detection area DA. The optical inspection device 1 can display an image through the display module 104 to mark the position of the inspection area DA on the upper surface 101 of the protective layer 100 when an inspection is needed.

Optionally, in some embodiments, the lens system 190 has a range of variation of the field angle such as, but not limited to: 100 to 140 degrees or 120 to 150 degrees.

Referring to fig. 7 to 10, the lens system 190 of the detection module 19 is an optical imaging system including one or more lenses, and is used for focusing and imaging the detection light beam 11 returned from the external object 1000 on the light sensing surface 198 of the image sensor 196. The lenses may be made, for example, by an injection molding process of a resin material, each lens having a pair of surfaces capable of deflecting light, an imaging beam passing through the lens entering the lens from one of the side surfaces and exiting the lens from the opposite side surface, which may be spherical or aspherical. Each of the surfaces includes an optical area for deflecting light rays, and the portion of the lens other than the optical area is mainly used for assembling and matching the lens.

Optionally, in some embodiments, the lens system 190 includes a first lens 191, a second lens 192, and a third lens 193 arranged in order along the optical axis OA from an object side to an image side. Wherein the first lens 191 has a negative optical power, the second lens 192 has a positive optical power, and the third lens 193 has a positive optical power.

As shown in fig. 8, the first lens 191 includes a first surface 1911 close to the object side and a second surface 1912 close to the image side. The first surface 1911 includes a first optical zone 1913 for deflecting light rays for imaging. The first optical zone 1913 is located in the middle portion of the first surface 1911 and is a centrosymmetric aspheric surface with a concave center position. The first optical zone 1913 has a first center point 1914, and the optical axis OA of the lens system 190 passes through the first center point 1914.

Fig. 8 is a cross-sectional view of the first lens 191 taken through a plane passing through the optical axis OA. With the first center point 1914 as the origin of coordinates, the direction from the object side to the image side along the optical axis OA is the positive direction z1 of the surface vector height coordinate axis, and the direction to the right along the perpendicular optical axis OA is the positive direction h1 of the radial coordinate axis of the first optical zone 1913, a coordinate system is established on the cross-sectional view of the first optical zone 1913 to mark the positions of the partial points on the first optical zone 1913. Wherein the absolute value of the radial coordinate value of the point on the first optical zone 1913 is in the range of 0mm (Millimeter, mm) to 1.3mm, and the surface sagittal coordinate value of the point on the first optical zone 1913 is in the range of-0.0190 mm to 0.25 mm. It is understood that in the above coordinate system, the absolute value of the radial coordinate value of a point on the first optical zone 1913 is the distance from the optical axis OA of the point. The correspondence between the surface rise coordinate values and the radial coordinate values of the seven representative points selected on the first optical zone 1913 is shown in the following table:

the second surface 1912 includes a second optical zone 1915 for deflecting light rays for imaging. The second optical zone 1915 is located in the middle portion of the second surface 1912 and is a centrosymmetric aspheric surface with a concave center. The second optical zone 1915 has a second center point 1916, and the optical axis OA of the lens system 190 passes through the second center point 1916. With the second center point 1916 as the origin of coordinates, the direction from the object side to the image side along the optical axis OA is the positive direction z2 of the surface vector height coordinate axis, the direction to the right along the perpendicular optical axis OA is the positive direction h2 of the radial coordinate axis of the second optical zone 1915, and a coordinate system is established on the cross-sectional view of the second optical zone 1915 to mark the positions of the partial points on the second optical zone 1915. Wherein the absolute value of the radial coordinate value of the point on the second optical zone 1915 ranges from 0mm to 0.5mm, and the variation range of the surface rise coordinate value of the second optical zone 1915 ranges from 0mm to 0.5000 mm. It is understood that in the above coordinate system, the absolute value of the radial coordinate value of a point on the second optical zone 1915 is the distance from the optical axis OA of the point. The correspondence between the surface rise coordinate values and the radial coordinate values of the three representative points selected on the second optical zone 1915 is shown in the following table:

the first center point 1914 of the first optical zone 1913 and the second center point 1916 of the second optical zone 1915 are aligned with each other along the optical axis OA, a distance T1 between the first center point 1914 and the second center point 1916 along the optical axis OA is a thickness of the first lens 191 along the optical axis OA, and the distance T1 may range from 0.22mm to 0.27 mm. Optionally, in some embodiments, the distance T1 is, for example: 0.23mm, 0.25mm, or 0.26 mm. The first lens 191 has an Effective Focal Length fl (EFL) measured at 632.8nm, and the Effective Focal Length f1 of the first lens 191 varies from-0.5 mm to-0.7 mm. Optionally, in some embodiments, the effective focal length f1 of the first lens 191 is, for example: -0.54mm, -0.60mm, or-0.68 mm.

As shown in fig. 9, the second lens element 192 includes a third surface 1923 close to the object side and a fourth surface 1924 close to the image side, the third surface 1923 is an aspheric surface convex toward the object side, and the fourth surface 1924 is an aspheric surface convex toward the image side. The third surface 1923 includes a third optical region 1921 for deflecting light rays for imaging. The third optical region 1921 is located in a middle portion of the third surface 1923, and is a centrosymmetric aspheric surface protruding toward the object side. The third optical region 1921 has a third center point 1922, and the optical axis OA of the lens system 190 passes through the third center point 1922.

Fig. 9 is a cross-sectional view of the second lens 192 taken through a plane passing through the optical axis OA. With the third center point 1922 as the origin of coordinates, the direction from the object side to the image side along the optical axis OA is the positive direction z3 of the surface vector height coordinate axis, the direction to the right along the vertical optical axis OA is the positive direction h3 of the radial coordinate axis of the third optical region 1921, and a two-dimensional coordinate system is established on the cross-sectional view of the third optical region 1921 to mark the positions of some points on the third optical region 1921. The absolute value of the radial coordinate value of a point on the third optical region 1921 ranges from 0mm to 0.5mm, and the value of the surface rise coordinate value of the third optical region 1921 ranges from 0mm to 0.0560 mm. It is understood that, in the coordinate system, an absolute value of a radial coordinate value of a point on the third optical region 1921 is a distance from the point to the optical axis OA. The correspondence between the surface vector height coordinate values and the radial coordinate values of the five representative points selected on the third optical region 1921 is shown in the following table:

the fourth surface 1924 includes fourth optical regions 1925 for deflecting light rays for imaging. The fourth optical region 1925 is located in the middle of the fourth surface 1924 and is a centrosymmetric aspheric surface convex towards the image side. The fourth optical region 1924 has a fourth center point 1926, and the optical axis OA of the lens system 190 passes through the fourth center point 1926. With the fourth center point 1926 as the origin of coordinates, the direction from the object side to the image side along the optical axis OA is the positive direction z4 of the surface vector height coordinate axis, the direction to the right along the vertical optical axis OA is the positive direction h3 of the radial coordinate values of the fourth optical region 1924, and a coordinate system is established on the cross-sectional view of the fourth optical region 1924 to mark the positions of the partial points on the fourth optical region 1924. The absolute value range of the radial coordinate value of the point on the fourth optical region 1924 is 0mm to 0.5mm, and the value range of the surface rise coordinate value of the fourth optical region 1924 is-0.0830 mm to 0 mm. It is understood that, in the coordinate system, an absolute value of a radial coordinate value of a point on the fourth optical region 1924 is a distance from the point to the optical axis OA. The correspondence between the surface rise values and the radial coordinate values of the five representative points selected on the fourth optical region 1924 is shown in the following table:

a third central point 1922 of the third optical region 1921 and a fourth central point 1926 of the fourth optical region 1925 are aligned with each other along the optical axis OA, a distance T2 between the third central point 1922 and the fourth central point 1926 along the optical axis OA is a thickness of the second lens 192 along the optical axis OA, and the variation range of the distance T2 may be 0.42mm to 0.46 mm. Optionally, in some embodiments, the distance T2 is, for example: 0.43mm, 0.44mm, or 0.45 mm. The second lens 192 has an effective focal length f2, and the effective focal length f2 of the second lens 192 ranges from 0.8mm to 1.2mm, as measured at 632.8 nm. Optionally, in some embodiments, the effective focal length f2 of the second lens 192 is, for example: 1.00mm, 1.06mm, or 1.15 mm.

As shown in fig. 10, the third lens 193 includes a fifth surface 1935 close to the object side and a sixth surface 1936 close to the image side. The fifth surface 1935 includes a fifth optical area 1931 for deflecting light rays for imaging. The fifth optical region 1931 is located in a middle portion of the fifth surface 1935, and is a centrosymmetric aspheric surface convex toward the object side. The fifth optical area 1931 has a fifth central point 1932, and the optical axis OA of the lens system 190 passes through the fifth central point 1932.

Fig. 10 is a cross-sectional view of the third lens 193 taken through a plane passing through the optical axis OA. Taking the fifth central point 1932 as an origin of coordinates, a direction from the object side to the image side along the optical axis OA being a positive direction z5 of a surface vector height coordinate axis, and a direction to the right along the vertical optical axis OA being a positive direction h5 of a radial coordinate axis of the fifth optical region 1931, and establishing a coordinate system on a cross-sectional view of the fifth optical region 1931. Wherein, the absolute value range of the radial coordinate axis of the point on the fifth optical area 1931 is 0mm to 0.45mm, and the value range of the surface rise coordinate value of the fifth optical area 1931 is-0.0550 mm to 0.015 mm. It is understood that, in the coordinate system, an absolute value of a radial coordinate value of a point on the fifth optical area 1931 is a distance from the point to the optical axis OA. The correspondence between the surface vector height coordinate values and the radial coordinate values of the five representative points selected on the fifth optical region 1931 is shown in the following table:

the sixth surface 1936 includes a sixth optical area 1933 for deflecting light rays for imaging. The sixth optical area 1933 is located in the middle of the sixth surface 1936 and is a centrosymmetric aspheric surface convex toward the image side. The sixth optical area 1933 has a sixth center point 1934, and the optical axis OA of the lens system 190 passes through the sixth center point 1934. Taking the sixth central point 1934 as an origin of coordinates, a direction from the object side to the image side along the optical axis OA is a positive direction z6 of a surface vector height coordinate axis, a direction to the right along the vertical optical axis OA is a positive direction h5 of a radial coordinate axis of the sixth optical area 1933, and a coordinate system is established on a cross-sectional view of the sixth optical area 1933. Wherein, the absolute value range of the radial coordinate value of the point on the sixth optical area 1933 is 0mm to 0.55mm, and the value range of the surface rise coordinate value of the sixth optical area 1933 is-0.45 mm to 0 mm. It is understood that, in the coordinate system, an absolute value of a radial coordinate value of a point on the sixth optical area 1933 is a distance from the point to the optical axis OA. The correspondence between the surface vector height coordinate values and the radial coordinate values of the six representative points selected on the sixth optical area 1933 is shown in the following table:

a fifth central point 1932 of the fifth optical area 1935 and a sixth central point 1934 of the sixth optical area 1936 are aligned with each other along the optical axis OA, a distance T3 between the fifth central point 1932 and the sixth central point 1934 along the optical axis OA is a thickness of the third lens 193 along the optical axis OA, and the variation range of the distance T3 may be 0.40mm to 0.45 mm. Optionally, in some embodiments, the distance T3 is, for example: 0.42mm, 0.43mm, or 0.44 mm. The third lens 193 has an effective focal length f3, and the effective focal length f3 of the third lens 193 ranges from 0.6mm to 1.0mm, measured with light having a wavelength of 632.8 nm. Optionally, in some embodiments, the effective focal length f3 of the third lens 193 is, for example: 0.65mm, 0.70mm, or 0.86 mm.

Center points 1914 and 1916 of

optical regions

1913 and 1915 on the first lens 191 and

center points

1922 and 1926 of

optical regions

1921 and 1925 on the second lens 192 are aligned with each other along an optical axis OA direction, wherein a distance D1 along the optical axis OA between a second center point 1916 of the first lens 191 facing the image side and a third center point 1922 of the second lens 192 facing the object side is a relative distance between the first lens 191 and the second lens 192, and the variation range of the distance D1 is 0.48mm to 0.52 mm. Optionally, in some embodiments, the distance D1 is, for example: 0.50 mm.

Center points 1922 and 1926 of

optical regions

1921 and 1925 and

center points

1932 and 1934 of

optical regions

1931 and 1933 on the second lens 192 and the third lens 193 are aligned with each other along an optical axis OA direction, a distance D2 between a fourth center point 1926 facing the image side of the second lens 192 and a fifth center point 1932 facing the object side of the third lens 193 along the optical axis OA is a relative distance between the second lens 192 and the third lens 193, and the distance D2 ranges from 0.19mm to 0.25 mm. Optionally, in some embodiments, the distance D2 is, for example: 0.22 mm.

The lens system 190 also has an effective focal length f as an imaging system, and the effective focal length f of the lens system 190 ranges from 0.20mm to 0.50mm when measured with light having a wavelength of 632.8 nm. Optionally, in some embodiments, the effective focal length f of the lens system is, for example: 0.25mm, 0.33mm, or 0.45 mm. The F number of the lens system is less than 1.3, and the relative illumination is greater than 46%.

Optionally, in some embodiments, the lens system 190 may further include a diaphragm 194. The stop 194 is located between the second lens 192 and the third lens 193. The diaphragm 194 is provided with a light through hole 1940, and the aperture of the light through hole 1940 ranges from 0.53mm to 0.75 mm. Optionally, in some embodiments, the aperture of the light passing hole 1940 is, for example: 0.55mm, 0.58mm, 0.64mm, or 0.73 mm. The detection light beam 11 modulated by the first lens 191 and the second lens 192 passes through the light-passing hole 1940 and is focused by the third lens 193 to be imaged on the light sensing surface 198 of the image sensor 196. The depth of field of the image of the lens system 190 and the brightness of the formed image can be correspondingly adjusted by adjusting the aperture of the light-passing hole 1940, and part of the imaging light with poor imaging quality and the stray light reflected by non-imaging objects can be eliminated, so that the imaging quality of the lens system 190 is improved.

Optionally, in some embodiments, the detection module 19 further includes a filter 195. The filter 195 is disposed between the third lens 193 and the light sensing surface 198 of the image sensor 196, and the thickness of the filter 195 along the optical axis OA direction ranges from 0.18mm to 0.23 mm. Optionally, the thickness of the filter 195 in the optical axis OA direction is, for example: 0.19mm, 0.21mm, or 0.23 mm. The distance D3 between the filter 195 and the sixth center point 1934 of the third lens 193 along the optical axis OA ranges from 0.36mm to 0.42 mm. Optionally, the distance D3 is, for example: 0.37mm, 0.39mm, or 0.41 mm. The filter 195 is used to filter out other light having a different wavelength from the detection beam 11, so as to reduce the influence of the other light on the imaging of the detection beam 11.

The sixth surface 1936 of the third lens 193 is the surface of the lens system 190 closest to the light sensing surface 198. Wherein a sixth center point 1934 on the sixth surface 1936 is a vertex of the sixth surface 1936 closest to the light sensing surface 198, and a distance D4 between the sixth center point 1934 and the light sensing surface 198 along an optical axis OA is a Back Focal Length (BFL) of the lens system 190. The spacing D4 may range from 0.6mm to 0.7mm, alternatively, in some embodiments, the spacing D4 is, for example, 0.63mm, 0.66mm, or 0.68 mm.

The first surface 1911 of the first lens 191 is a lens surface farthest from the light sensing surface 198 in the lens system 190. A distance D5 between the first central point 1914 of the first surface 1911 and the light sensing surface 198 along the optical axis OA is an optical total length of the lens system 190, and the distance D5 ranges from 2.0mm to 3.0 mm. Optionally, in some embodiments, the distance D5 is, for example: 2.52 mm.

The display screen 12 includes a protection layer 100 and a display module 104 located below the protection layer 100, an upper surface 101 of the protection layer 100 is an outer surface of the display screen 12 located at an outermost side, the display module 104 includes a bottom surface 1040 facing the detection module 19, and the bottom surface 1040 of the display module 104 is a bottom surface of the display screen 12. When the external object 1000 touches the outer surface 101 of the display screen 12 during detection, the lens system 190 located below the display screen 100 images the external object 1000 in contact with the outer surface 101 of the display screen 12 on the light sensing surface 198 of the image sensor 196. The outer surface 101 of the display 12 is the object plane of the whole optical imaging system, and the light sensing surface 198 of the image sensor 196 is the image plane of the whole optical imaging system. The field area VA of the lens system 190 on the outer surface 101 of the display screen 12 is the maximum area that the lens system 190 can image on the object plane. The field area VA has a field center 15, and the optical axis OA of the lens system 19 passes through the field center 15. The distance D6 between the points on the boundary of the field of view area VA and the field of view center 15 reflects the size of the field of view area VA to some extent, and the distance D6 ranges from 3mm to 5 mm. Optionally, in some embodiments, the field of view area is circular or elliptical, and the separation distance D6 is, for example, 3.2mm, 4.16mm, or 4.73 mm. The variation range of the maximum image height of the image formed by the lens system 190 on the light sensing surface 198 is 1.0mm to 1.5 mm. Optionally, in some embodiments, the maximum image height is, for example: 1.16mm, 1.36mm, or 1.45 mm. The distance D7 between the bottom surface 1040 of the display screen 12 and the light sensing surface 198 along the optical axis OA direction is the total optical length of the optical detection device 10, and the variation range of the distance D7 is 3mm to 4 mm. Optionally, in some embodiments, the distance D7 is, for example: 3.25mm, 3.49mm, 3.68mm or 3.79 mm. The surface of the first lens 191 closest to the display screen 12 is a first surface 1911, a distance D8 between a first central point 1914 of a first optical zone 1913 on the first surface 1911 and the outer surface 101 of the display screen 12 along the optical axis OA direction is an object distance of the optical detection apparatus 10, and the distance D8 varies from 2.3mm to 2.8 mm. Optionally, in some embodiments, the distance D8 is, for example, 2.45mm, 2.59mm, 2.64mm, or 2.73 mm. A distance D9 between the bottom surface 1040 of the display screen 12 and the first center point 1914 of the first lens 191 along the optical axis OA direction is an Air gap (Air gap) between the detection module 19 and the display screen 12, and the variation range of the distance D9 is 0.8mm to 1.2 mm. Optionally, in some embodiments, the distance D9 is, for example: 0.85mm, 0.99mm, 1.05mm, or 1.16 mm.

As shown in fig. 11 and 12, fig. 11 is a graph of Modulation Transfer Function (MTF) of the lens system 190 as a Function of Spatial Frequency (Spatial Frequency) of a sample stripe, and fig. 12 is a graph of optical Transfer Function (MTF) of the lens system 190 as a Function of image height size. As can be seen from fig. 11 and 12, the MTF value of the image formed by the lens system 190 on the optical axis OA for the stripe with a spatial frequency of 50 (line pair/mm, lp/mm) is greater than 0.8, and the MTF value in the image height range of 70% is greater than 0.5, so that it can be seen that the lens system 190 has a high resolution in most of the imaging range. As shown in fig. 13 and 14, fig. 13 is an optical distortion diagram of the lens system 190, and fig. 14 is an astigmatic field curvature diagram of the lens system. As can be seen from fig. 13 and 14, the optical distortion of the lens system 190 is less than 4%, and the difference between the focal positions of the meridional rays T and the sagittal rays S is small in most regions of the imaging range, so that the lens system 190 has a good image restoration capability. To sum up, the lens system 190 provided by the embodiment of the present application has the characteristics of a wide angle and a short focus, a wide field angle range, a small optical total length, and the like, and can meet the requirements of small space and high optical imaging quality of sensing under a screen.

In the embodiments and modifications of the present application, the optical detection device 10 may be a mobile phone, a tablet computer, an intelligent watch, an augmented reality/virtual reality device, a human body motion detection device, an auto-driven automobile, an intelligent home device, a security device, a medical device, an intelligent robot, or the like, or any of the above components.

It will be appreciated that although fingerprints are generally described in the context of this application for illustrative purposes, the lens system and its modified embodiments are not limited to detection of fingerprints, and the detection object of the lens system and its modified embodiments can be any object to be imaged. Generally, a test object may have various characteristics including a biological characteristic. It should be noted that, as an example, the embodiment of the present invention is described with a finger print as a detection object, and it can be understood that lines such as a palm, a toe, a palm print, and a skin surface texture can also be used as features of the detection object or an external object to be detected.

It should be noted that the optical detection device 10 and other or other embodiments are described in the embodiments of the present application, and the structures, numbers, positions, driving methods, and the like of the light source module 16, the detection module 19, the protection layer 100, the optical film layer 107, the display module 104, the lens, the image sensor, and the like can be applied to the embodiments described in the present application and other or modified embodiments, and the replacement, modification, extension, arrangement, combination, matching, increase/decrease, omission, multiplexing, and the like of the embodiments are all within the scope of protection of the present application.

It should be noted that, those skilled in the art can understand that, without creative efforts, some or all of the embodiments of the present invention, and some or all of the deformation, replacement, alteration, split, combination, extension, etc. of the embodiments should be considered as covered by the inventive idea of the present invention, and belong to the protection scope of the present invention.

Any reference in this specification to "one embodiment," "an embodiment," "example embodiment," etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature or structure is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature or structure in connection with other ones of the embodiments.

The orientations or positional relationships indicated in the specification of "length", "width", "upper", "lower", "left", "right", "front", "rear", "back", "front", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., which may appear in the present invention, are orientations or positional relationships indicated on the basis of the drawings, and are only for convenience of describing the embodiments of the present invention and simplifying the description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Like reference numbers and letters refer to like items in the figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures. Meanwhile, in the description of the present invention, the terms "first", "second", and the like are used only for distinguishing the description, and are not to be construed as indicating or implying relative importance. In the description of the present invention, "plurality" or "a plurality" means at least two or two unless specifically defined otherwise. In the description of the present invention, it should be noted that, unless explicitly stated or limited otherwise, "disposed," "mounted" or "connected" is to be understood in a broad sense, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; either directly or indirectly through intervening media, or may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The above description is only for the specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto, and any person skilled in the art can easily think of the changes or substitutions within the technical scope of the present invention, and all should be covered within the protection scope of the present invention. The terms used in the following claims should not be construed to limit the invention to the specific embodiments disclosed in the specification. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A lens system is characterized by comprising a first lens with negative focal power, a second lens with positive focal power and a third lens with positive focal power which are sequentially arranged from an object side to an image side along an optical axis;

2. A lens system according to claim 1, wherein, in the first optical region, a surface rise corresponding to a point at a distance of 0.2mm from the optical axis is-0.0093 mm, a surface rise corresponding to a point at a distance of 0.4mm from the optical axis is-0.0181 mm, a surface rise corresponding to a point at a distance of 0.6mm from the optical axis is-0.0089 mm, a surface rise corresponding to a point at a distance of 0.8mm from the optical axis is 0.0221mm, a surface rise corresponding to a point at a distance of 1.0mm from the optical axis is 0.0785mm, and the surface rise corresponding to a point at a distance of 1.2mm from the optical axis is 0.1944 mm.

3. The lens system according to claim 1, characterized in that, on the second optical region, a point at a distance of 0.2mm from an optical axis corresponds to a surface rise of 0.0508mm, and a point at a distance of 0.4mm from an optical axis corresponds to a surface rise of 0.2562 mm.

4. The lens system according to claim 1, characterized in that, on the third optical region, a surface rise corresponding to a point at a distance of 0.1mm from an optical axis is 0.0055mm, a surface rise corresponding to a point at a distance of 0.2mm from an optical axis is 0.0210mm, a surface rise corresponding to a point at a distance of 0.3mm from an optical axis is 0.0416mm, and a surface rise corresponding to a point at a distance of 0.4mm from an optical axis is 0.0528 mm.

5. The lens system according to claim 1, characterized in that, on the fourth optical region, a surface rise of-0.0031 mm corresponding to a point at a distance of 0.1mm from the optical axis, a surface rise of-0.0136 mm corresponding to a point at a distance of 0.2mm from the optical axis, a surface rise of-0.0357 mm corresponding to a point at a distance of 0.3mm from the optical axis, and a surface rise of-0.0793 mm corresponding to a point at a distance of 0.4mm from the optical axis.

6. The lens system according to claim 1, characterized in that, on the fifth optical region, a surface rise corresponding to a point at a distance of 0.1mm from the optical axis is 0.0036mm, a surface rise corresponding to a point at a distance of 0.2mm from the optical axis is 0.0110mm, a surface rise corresponding to a point at a distance of 0.3mm from the optical axis is 0.0104mm, and a surface rise corresponding to a point at a distance of 0.4mm from the optical axis is-0.0531 mm.

7. The lens system according to claim 1, characterized in that, on the sixth optical region, a surface rise of-0.0107 mm corresponds to a point at a distance of 0.1mm from the optical axis, a surface rise of-0.0427 mm corresponds to a point at a distance of 0.2mm from the optical axis, a surface rise of-0.0972 mm corresponds to a point at a distance of 0.3mm from the optical axis, a surface rise of-0.1852 mm corresponds to a point at a distance of 0.4mm from the optical axis, and a surface rise of-0.3794 corresponds to a point at a distance of 0.5mm from the optical axis.

8. The lens system according to claim 1, wherein a thickness of the first lens along the optical axis varies from 0.22mm to 0.27mm, an effective focal length of the first lens varies from-0.5 mm to-0.7 mm, a thickness of the second lens along the optical axis varies from 0.42mm to 0.46mm, an effective focal length of the second lens varies from 0.8mm to 1.2mm, a thickness of the third lens along the optical axis varies from 0.40mm to 0.45mm, and an effective focal length of the third lens varies from 0.6mm to 1.0 mm.

9. The lens system according to claim 1, wherein a variation range of a distance between the second center point and the third center point along the optical axis is 0.48mm to 0.52mm, and a variation range of a distance between the fourth center point and the fifth center point along the optical axis is 0.19mm to 0.25 mm.

10. The lens system according to any one of claims 1 to 9, wherein an optical distortion of the lens system is less than 4%, an effective focal length of the lens system varies from 0.20mm to 0.50mm, an F-number of the lens system is less than 1.3, and a field angle of the lens system is greater than 125 degrees.

11. A detection module, comprising a lens system as claimed in any one of claims 1 to 10 and an image sensor disposed on an image side of the lens system, wherein the image sensor includes a light sensing surface for receiving a light signal transmitted by the lens system and converting the light signal into a corresponding electrical signal to implement detection, and the light sensing surface is an imaging surface of the lens system.

12. The detecting module according to claim 11, wherein a distance between the sixth center point and the photo-sensing surface along the optical axis ranges from 0.6mm to 0.7mm, and a distance between the first center point of the first lens and the photo-sensing surface along the optical axis ranges from 2mm to 3 mm.

13. The detecting module of claim 11, wherein the maximum image height imaged on the light sensing surface varies from 1.0mm to 1.5 mm.

14. An optical inspection apparatus, comprising:

the detection module of any one of claims 11 to 13, located below the lower surface, the detection module configured to receive a detection beam returned by an external object to image a portion of the external object touching the upper surface.

15. The optical inspection device of claim 14, wherein the upper surface of the protection layer is an object plane of the lens system, and a distance between the upper surface of the protection layer and the first center point along the optical axis varies from 2.3mm to 2.8 mm.

16. The optical inspection device as claimed in claim 14, wherein the lens system has a predetermined field angle range, an area of the upper surface of the protective layer within the field angle range is defined as a field area, the field area has a field center, the optical axis of the lens system passes through the field center, and the distance between a point on the boundary of the field area and the field center varies from 3mm to 5 mm.

17. The optical inspection device of claim 14, wherein the display module includes a bottom surface facing the inspection module, a variation range of a distance between the bottom surface of the display module and the first center point along the optical axis is 0.8mm to 1.2mm, and a variation range of a distance between the bottom surface of the display module and the light sensing surface along the optical axis is 3mm to 4 mm.