CN111709330B - Optical detection system and electronic equipment - Google Patents

Abstract

The application discloses an optical detection system, which comprises a first lens and a second lens with overlapping field of view ranges, an image sensor positioned below the first lens and the second lens, and a processor. The image sensor includes a plurality of first photosensitive units and a plurality of second photosensitive units, respectively. The first photosensitive unit is used for receiving the imaging light converged by the first lens and converting the imaging light into corresponding electric signals. The second photosensitive unit is used for receiving the light rays focused and imaged by the second lens and converting the light rays into corresponding electric signals. The processing module is used for comparing differences of images formed by the external objects in the overlapping view field range through the first lens and the second lens respectively, and judging that the external objects are three-dimensional objects when the differences are larger than or equal to a preset threshold value. The application also discloses an optical detection system and electronic equipment.

Description

Optical detection systems and electronic equipment

Technical field

The present application relates to the field of optoelectronic technology, and in particular to an optical detection system and electronic equipment that utilize optical imaging principles to detect external objects.

Background technique

At present, the optical fingerprint recognition function of electronic products such as mobile phones and tablet computers is usually realized by identifying the flat fingerprint image obtained when the user's finger presses the surface of the screen. It is relatively easy for criminals to break through low-cost flat fake fingerprint props, such as: Attach the tape or picture printed with the fingerprint pattern to the fingerprint recognition area on the screen surface. Therefore, the optical fingerprint recognition function of existing electronic products has obvious security risks.

Contents of the invention

In view of this, the present invention provides an optical detection system and electronic equipment that can improve the problems of the existing technology.

One aspect of the present application provides an optical detection system for detecting an external object, which is characterized by including:

A first lens having a first field of view range and used for imaging external objects within the first field of view range;

The second lens has a second field of view range and is used for imaging external objects within the second field of view range. The first field of view range and the second field of view range at least partially overlap, defining the first field of view range. The overlapping portion of the field range and the second field of view range is the overlapping field of view range;

An image sensor is located below the first lens and the second lens. The image sensor includes a plurality of first photosensitive units and a plurality of second photosensitive units. The first photosensitive units are used to receive images through the first lens. The concentrated imaging light is converted into a corresponding electrical signal, and the second photosensitive unit is used to receive the light condensed and imaged by the second lens and converted into a corresponding electrical signal;

A processing module for comparing the difference between the first image formed by the first lens and the second image formed by the second lens of the external object within the overlapping field of view, and when the difference is When it is greater than or equal to the preset threshold, it is determined that the external object is a three-dimensional object.

In some embodiments, a lens module is further included. The lens module is located below the display screen. The lens module includes a plurality of small lenses arranged in an array. The first lens and the second lens are respectively One of the plurality of small lenses.

In some embodiments, the external object includes a first feature point and a second feature point, and the distance between the corresponding image points of the first feature point and the second feature point on the first image is A distance, the distance between the corresponding image points of the first feature point and the second feature point on the second image is the second distance, and the difference between the first image and the second image is the The difference between the first spacing and the second spacing, the preset threshold is the threshold of the difference between the first spacing and the second spacing.

In some embodiments, the external object includes a first feature point and a second feature point, and the difference between the grayscale values of the corresponding image points of the first feature point and the second feature point on the first image is is the first grayscale difference. The difference between the grayscale values of the corresponding image points of the first feature point and the second feature point on the second image is the second grayscale difference. The first image and the second grayscale difference are The difference between the images is the difference between the first grayscale difference and the second grayscale difference, and the preset threshold is the threshold of the difference between the first grayscale difference and the second grayscale difference.

In some embodiments, the external object is a part of the fingerprint pattern of the user's finger located within the overlapping field of view, the first feature point is a fingerprint ridge, and the second feature point is a fingerprint valley.

In some embodiments, the distance between the image points formed by the first feature point and the second feature point on the first image and the second image respectively ranges from 100 μm to 300 μm.

In some embodiments, the proportion of the overlapping field of view range in the first field of view range and the second field of view range is greater than or equal to 30%.

In some embodiments, the display screen is an active light-emitting display screen, and the light emitted by the display screen can be used to illuminate external objects to form the first image and/or the second image; or

The display screen is a passive light-emitting display module, and the under-screen optical detection system also includes an excitation light source for providing light required for detection.

In some embodiments, the processing module is also configured to compare the first image and/or the second image of the external object with a pre-stored external object template, and identify the external object according to the comparison result. identity.

One aspect of the present application provides an electronic device, including the optical detection system provided in the above embodiment.

The beneficial effect of the present application is that the optical detection system of the present application determines whether the external object is a three-dimensional object by comparing whether there are differences due to parallax between external object images obtained from different viewing angles, which can effectively prevent criminals from taking advantage of Flat imitations printed with images of external objects attack the recognition function of the optical detection system and improve the security of electronic equipment.

Description of the drawings

Figure 1 is a schematic structural diagram of an under-screen optical detection system provided by an embodiment of the present application applied to an electronic device;

Figure 2 is a three-dimensional structural view of the optical detection system according to the first embodiment of the present application;

Figure 3 is a partial cross-sectional schematic diagram of the optical detection system shown in Figure 2 along line III-III;

Figure 4 is an imaging optical path diagram of the first lens and the second lens described in Figure 3;

Figure 5 is a schematic diagram of the functional modules of the optical detection system according to the first embodiment of the present application;

Figure 6 is a partial cross-sectional schematic diagram of the optical detection system according to the second embodiment of the present application;

Specific embodiments

In the detailed description of the embodiments of the present application, it should be understood that when a substrate, sheet, layer or pattern is referred to as being "on" or "under" another substrate, another sheet, another layer or another pattern, it It may be "directly" or "indirectly" on another substrate, another sheet, another layer or another pattern, or one or more intermediate layers may also be present. For purposes of clarity, the thickness and size of each layer in the drawings of this specification may be exaggerated, omitted, or schematically represented. In addition, the sizes of components in the drawings do not entirely reflect actual sizes.

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this application.

The following disclosure provides many different embodiments or examples for implementing different structures of the present application. To simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the application. Furthermore, this application may repeat reference numbers and/or reference letters in different examples, such repetition being for the purposes of simplicity and clarity and does not by itself indicate a relationship between the various embodiments and/or arrangements discussed. In addition, this application provides examples of various specific processes and materials, but one of ordinary skill in the art will recognize the application of other processes and/or the use of other materials.

Further, the described features and structures 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 present application. However, those skilled in the art should realize that the technical solution of the present application can also be practiced without one or more of the specific details, or by adopting other structures, components, etc. In other instances, well-known structures or operations are not shown or described in detail to avoid obscuring the disclosure.

Please refer to FIG. 1 , which is a schematic structural diagram of an embodiment of the electronic device of the present application. The electronic device 1 includes an under-screen optical detection system 10 for detecting external objects 2 . The under-screen optical detection system 10 includes a protective layer 12 , a display screen 14 and an optical detection system 16 located below the display screen 14 . The display screen 14 is located below the protective layer 12 . The display screen 14 is used to display images. The protective layer 12 can transmit the light emitted by the display screen 14 for displaying images and protect the display screen 14 from damage. The optical detection system 16 is used to receive light from the external object 2 through the protective layer 12 and the display screen 14, and convert the received light into corresponding electrical signals to perform corresponding information sensing. The optical detection system 16 is, for example, used to perform sensing of biometric information, such as but not limited to fingerprint information, palmprint information and other texture feature information, and/or blood oxygen information, heartbeat information, and pulse information. and other living body information. However, the present application is not limited to this, and the optical detection system 16 can also be used to perform other information sensing, such as depth information sensing, proximity sensing, and so on. In this application, the external object 2 is a user's finger and the optical detection system 16 performs fingerprint sensing as an example for explanation.

The electronic device 1 is, for example, but not limited to suitable types of electronic products such as consumer electronic products, household electronic products, vehicle-mounted electronic products, financial terminal products, etc. Among them, consumer electronic products include mobile phones, tablet computers, notebook computers, desktop monitors, all-in-one computers, etc. Home electronic products include smart door locks, TVs, refrigerators, etc. Vehicle-mounted electronic products include vehicle navigation systems, vehicle-mounted touch interactive devices, and the like. Financial terminal products include ATM machines, self-service terminals, etc.

It should be noted in advance that in this application, the optical detection system 16 has multiple different embodiments. For the sake of clarity, the optical detection systems 16 in different embodiments are labeled with different numbers 16a and 16b respectively. Make a distinction. Furthermore, for the convenience of description, the same reference numerals in different embodiments of the optical detection system 16 may represent the same components, or may represent similar components that have been modified, replaced, expanded, or combined.

Optionally, in some embodiments, the display screen 14 may be an active light-emitting display screen, such as but not limited to an organic light-emitting diode display screen (OLED display screen). The display screen 14 can be used as an excitation light source to provide light for detection, such as but not limited to visible light with a wavelength range between 400 and 780 nanometers (nm). Alternatively, in other embodiments, the display screen 14 may also be a passive light-emitting display screen, such as but not limited to a liquid crystal display screen (LCD screen) or an electronic paper display screen. The electronic device 1 using a passive light-emitting display screen requires an additional excitation light source to provide light for detection, such as but not limited to near-infrared light with a wavelength range between 800 and 1000 nm. However, alternatively, an electronic device using an active light-emitting display screen may be additionally provided with an excitation light source to provide light for detection.

Optionally, in some embodiments, the protective layer 12 may include transparent materials, such as but not limited to transparent glass, transparent polymers, any other transparent materials, and the like. The protective layer 12 may have a single-layer structure or a multi-layer structure. The protective layer 12 is generally a thin plate with a predetermined length, width, and thickness. It can be understood that the protective layer 12 may include a plastic film, a tempered film, or other film layers attached by the user during actual use. The outer surface 120 of the protective layer 12 may be the outermost surface of the electronic device 1 . During detection, the external object 2 may directly contact the outer surface 120 of the protective layer 12 .

Please refer to Figures 2, 3 and 5 together. Figure 2 is a three-dimensional structural view of the optical detection system 16a in the first embodiment of the present application. FIG. 3 is a partial cross-sectional view of the optical detection system 16a shown in FIG. 2 along line III-III. FIG. 5 is a schematic diagram of the functional modules of the optical detection system 16a according to the first embodiment of the present application. The optical detection system 16a includes a lens module 160 and an image sensor 162 disposed below the lens module 160. The lens module 160 is used to collect light to the image sensor 162 to image the external object 2 . The image sensor 162 is used to convert the received light into corresponding electrical signals.

The lens module 160 includes a plurality of small lenses 1600 (Mini-Lens). The plurality of small lenses 1600 are disposed above the image sensor 162 and are spaced apart from each other. The plurality of small lenses 1600 are used to focus light onto the image sensor 162 to image the external object 2 .

Optionally, in this embodiment, the plurality of small lenses 1600 are arranged in a regular array. Further optionally, the plurality of small lenses 1600 may be arranged in a rectangular array, for example but not limited to. However, alternatively, in other embodiments, the plurality of small lenses 1600 may also be arranged irregularly.

Optionally, in this embodiment, the lens module 160 further includes a first substrate 1603, and the plurality of small lenses 1600 are provided on the first substrate 1603. The first substrate 1603 is made of transparent material, such as but not limited to transparent acrylic resin, lens glass, UV glue, etc. The first substrate 1603 may be integrally formed with the plurality of small lenses 1600 . Alternatively, the plurality of small lenses 1600 and the first substrate 1603 are components produced independently of each other, and the plurality of small lenses 1600 are fixed on the first substrate 1603 through adhesive or other means.

Optionally, the plurality of small lenses 1600 are convex lenses. Further optionally, the plurality of small lenses 1600 are spherical lenses or aspherical lenses.

Optionally, the plurality of small lenses 1600 are made of transparent materials, such as but not limited to transparent acrylic resin, lens glass, UV glue, etc.

Optionally, in this embodiment, the optical detection system 16 further includes a second substrate 163 located below the image sensor 162 . The second substrate 163 may provide support for the image sensor 162 and electrical connection with external circuitry. The second substrate 163 is, for example, a flexible circuit board or a rigid circuit board.

Optionally, in this embodiment, the optical detection system 16 further includes a filter layer 164 disposed on the image sensor 162 . The filter layer 164 transmits light for detection within a preset wavelength range and filters out other light outside the preset wavelength range. Optionally, in some other embodiments, the filter layer 164 can also be coated on the light incident surfaces of the plurality of small lenses 1600 .

Optionally, in this embodiment, the optical detection system 16a further includes a light-shielding layer 165, which is provided on the first substrate 1603 and located in the spacing area between the plurality of small lenses 1600. . The light-shielding layer 165 is used to block light to reduce stray light that is not condensed by the small lens 1600 from irradiating the image sensor 162 and causing interference to detection.

Alternatively, in other embodiments, the light-shielding layer 165 may be disposed at different positions. For example, the light-shielding layer 165 is disposed between the light filter layer 164 and the first substrate 1603, and the light-shielding layer 165 has light-transmitting holes (not shown) corresponding to the plurality of small lenses 1600. Alternatively, the light-shielding layer 165 is disposed between the filter layer 164 and the image sensor 162 , and the light-shielding layer 165 has light-transmitting holes corresponding to the plurality of small lenses 1600 . This application is not limited to this.

Optionally, in other embodiments, the optical detection system 16 may also include a protective film (not shown) disposed on the plurality of small lenses 1600 . The protective film can cover the plurality of small lenses 1600 and/or the light-shielding layer 165 to prevent moisture, dust, scratches, etc. In some embodiments, the protective film can also be omitted.

The image sensor 162 includes a plurality of photosensitive units 1624 as well as readout circuits and other auxiliary circuits electrically connected to the photosensitive units 1624 . The photosensitive unit 1624 is a photo detector such as but not limited to a photodiode. The photosensitive unit 1624 is used to receive the imaging light collected by the lens module 160 and convert it into a corresponding electrical signal to obtain the biometric information of the external object 2 . The external object 2 is, for example, but not limited to, the user's finger, palm, etc., and the biometric information is, for example, but not limited to, the fingerprint image data of the user's finger. Optionally, the area size of a single photosensitive unit 1624 ranges from 5 microns (μm)*5 μm to 10 μm*10 μm, for example.

Optionally, in this embodiment, the plurality of photosensitive units 1624 are arranged in an array. However, alternatively, in some embodiments, the arrangement of the plurality of photosensitive units 1624 may also form a regular or irregular two-dimensional pattern. Each of the small lenses 1600 has a preset field of view (Filed Of View, FOV), and each of the small lenses 1600 is capable of imaging the external objects 2 within the field of view on multiple corresponding areas of the image sensor 162 . on the photosensitive unit 1624, and then converted into corresponding image data.

For the convenience of description, the area where the plurality of photosensitive units 1624 that can receive light through the small lens 1600 is defined as the photosensitive area of the small lens 1600. Some or all of the plurality of small lenses 1600 are in the image. Each sensor 162 has a corresponding photosensitive area. In this application, each small lens 1600 has a corresponding photosensitive area on the image sensor 162 as an example for description. Each of the small lenses 1600 can image the external object 2 within the respective field of view in the corresponding photosensitive area. Optionally, in this embodiment, the photosensitive area of each small lens 1600 includes a plurality of photosensitive units 1624, such as but not limited to: an array of 10*10 photosensitive units 1624, or a 100*100 photosensitive unit. An array of units 1624, or an array of photosensitive units 1624 of any size between 10*10 and 100*100, or 100 to 10,000 photosensitive units 1624.

Optionally, in this embodiment, each of the small lenses 1600 has the same shape and optical parameters, such as but not limited to: the same focal length, field of view range, surface curvature, etc. The photosensitive surface of the photosensitive unit 1624 on the image sensor 162 is substantially parallel to the outer surface of the protective layer 12 . The plurality of small lenses 1600 are disposed on the same horizontal plane. The optical centers of the multiple small lenses 1600 are aligned with the corresponding photosensitive surfaces. The distance between the photosensitive surfaces of the units 1624 is approximately the same, and the distance between the optical centers of the plurality of small lenses 1600 and the outer surface 120 of the protective layer 12 is also approximately the same. Therefore, in this embodiment, the imaging light path formed by each small lens 1600 and the corresponding photosensitive unit 1624 has the same imaging parameters, such as but not limited to: the same image distance and magnification. However, alternatively, in some other embodiments, the plurality of small lenses 1600 may also have different shapes and optical parameters.

Taking the external object 2 as the user's finger as an example, when detecting the fingerprint of the finger, the user presses the finger on the preset detection area on the outer surface 120 of the protective layer 12 , and the fingerprint of the finger is consistent with the detection area of the outer surface 120 of the protective layer 12 contact. It can be understood that the detection area is located within the field of view of the plurality of small lenses 1600, and the plurality of small lenses 1600 can image the fingerprint in contact with the detection area on the image sensor 162 corresponding to the respective field of view. on the photosensitive area, and converted into corresponding fingerprint image data by the photosensitive unit 1624 in the photosensitive area. The fingerprint of the finger includes a ridge and a valley. The ridge of the fingerprint is in direct contact with the surface of the protective layer 12 , and the valley of the fingerprint is separated from the surface of the protective layer 12 by a certain gap. Because the ridges and valleys have different contact conditions with the surface of the protective layer 12, the imaging light from the ridges and valleys respectively has different light intensities when they reach the corresponding photosensitive units 1624 (it can be considered that the brightness of the light is different). This results in a light and dark fingerprint image corresponding to the ridge and valley lines. The fingerprint image includes feature point information of multiple ridge and valley lines, which can be used to detect and identify fingerprints by further comparing and verifying it with pre-stored fingerprint template data.

One of the plurality of small lenses 1600 is defined as a first lens 1601, which has a corresponding first field of view range FOV1. The image sensor 162 has a first photosensitive area 1621 corresponding to the first lens 1601, and the photosensitive unit 1624 in the first photosensitive area 1621 is defined as a first photosensitive unit 1624a. The first lens 1601 is used to image the external object 2 within the first field of view range FOV1. The first photosensitive unit 1624a receives the light condensed and imaged by the first lens 1601 and converts it into corresponding image data (such as :electric signal). The first lens 1601 and the first photosensitive unit 1624a constitute a first imaging module 166 capable of imaging the external object 2 within the first field of view range FOV1.

Another one of the plurality of small lenses 1600 is defined as a second lens 1602, which has a corresponding second field of view range FOV2. The image sensor 162 has a second photosensitive area 1622 corresponding to the second lens 1602, and the photosensitive unit 1624 in the second photosensitive area 1622 is defined as a second photosensitive unit 1624b. The second lens 1602 is used to image the external object 2 within the second field of view range FOV2. The second photosensitive unit 1624b receives the light condensed and imaged by the second lens 1602 and converts it into corresponding image data (such as :electric signal). The second lens 1602 and the second photosensitive unit 1624b constitute a second imaging module 168 capable of imaging the external object 2 within the second field of view range FOV2.

The first field of view range FOV1 and the second field of view range FOV2 at least partially overlap, and the overlapping portion of the first field of view range FOV1 and the second field of view range FOV2 is defined as an overlapping field of view range. The first imaging module 166 forms a first image for the external object 2 (such as a user's finger) within the overlapping field of view, and the second imaging module 168 forms a second image for the external object 2 within the overlapping field of view. image.

As shown in FIG. 4 , FIG. 4 is an imaging optical path diagram of the first lens and the second lens in FIG. 3 . The external object 2 includes a first feature point A and a second feature point B. The first feature point A has a corresponding first imaging point A1 on the first image. The second feature point B has a corresponding first imaging point A1 on the first image. has a corresponding second imaging point B2 on the second image, the first feature point A has a corresponding third imaging point A3 on the second image, and the second feature point B has a corresponding fourth imaging point on the second image B4.

If the external object 2 is a planar object, such as but not limited to: tape or pictures printed with fingerprint patterns, etc. The planar external object 2 includes a first feature point A and a second feature point C. When the planar external object 2 is placed on the detection area within the overlapping field of view, all points on the planar external object 2 are in contact with the surface of the detection area within the overlapping field of view, and the first imaging module 166 The first image formed by the planar external object 2 within the overlapping field of view is consistent with the second image formed by the second imaging module 168 of the planar external object 2 within the overlapping field of view.

Specifically, the distance between the first imaging point A1 corresponding to the first feature point A on the first image and the second imaging point C2 corresponding to the second feature point C on the first image can be defined as First pitch A1C2. The distance between the third imaging point A3 corresponding to the first feature point A on the second image and the fourth imaging point C4 corresponding to the second feature point C on the second image can be defined as the second distance A3C4 . The consistency between the first image and the second image means that there is no difference between the first image and the second image or that the difference is less than a preset threshold, which is reflected in the image size as the distance between the first distance A1C2 and the second image. The second distance A3C4 is the same, or the difference between the first distance A1C2 and the second distance A3C4 is less than a preset difference threshold. The difference in gray value between the first imaging point A1 corresponding to the first feature point A on the first image and the second imaging point C2 corresponding to the second feature point C on the first image can be defined as The first grayscale difference. The difference in gray value between the third imaging point A3 corresponding to the first feature point A on the second image and the fourth imaging point C4 corresponding to the second feature point C on the second image can be defined as Second grayscale difference. The consistency between the first image and the second image in terms of image grayscale is reflected in the fact that the first grayscale difference is the same as the second grayscale difference, or the first grayscale difference is the same as the second grayscale difference. The difference between the differences is less than the preset difference threshold.

If the external object 2 is a three-dimensional object, such as but not limited to: the user's finger, when the three-dimensional finger is in surface contact with the detection area within the overlapping field of view, the fingerprint ridge of the three-dimensional finger will be in contact with the detection area within the overlapping field of view. The surface is in contact with a certain distance between the fingerprint valley and the surface of the detection area. There will be factors between the first image formed by the first imaging module 166 on the stereoscopic fingers within the overlapping field of view and the second image formed by the second imaging module 168 on the stereoscopic fingers within the overlapping field of view. Differences caused by parallax. Therefore, by analyzing whether there are differences between the images of the same external object 2 obtained from different viewing angles, it can be determined whether the external object 2 is three-dimensional, thereby preventing criminals from using flat imitations printed with images of the external object 2 to damage all objects. The recognition function of the optical detection system 16 is attacked.

Specifically, the fingerprint ridge of the three-dimensional finger is the first feature point A, and the fingerprint valley of the three-dimensional finger is the second feature point B. The fingerprint ridge A corresponds to the third feature point on the first image. The distance between an imaging point A1 and the second imaging point B2 corresponding to the fingerprint valley B on the first image can be defined as the first distance A1B2. The distance between the third imaging point A3 corresponding to the fingerprint ridge A on the second image and the fourth imaging point B4 corresponding to the fingerprint valley B on the second image may be defined as the second distance A3B4. The difference between the first image and the second image in terms of image size is reflected in the fact that the difference between the first distance A1B2 and the second distance A3B4 is greater than or equal to a preset difference threshold. The difference in gray value between the first imaging point A1 corresponding to the fingerprint ridge A on the first image and the second imaging point B2 corresponding to the fingerprint valley B on the first image can be defined as the first Grayscale difference. The difference in gray value between the third imaging point A3 corresponding to the fingerprint ridge A on the second image and the fourth imaging point B4 corresponding to the fingerprint valley B on the second image can be defined as the second Grayscale difference. The difference between the first image and the second image is reflected in the image grayscale in that the difference between the first grayscale difference and the second grayscale difference is greater than or equal to a preset difference threshold.

Optionally, in this embodiment, the first feature point A and the second feature point B of the external object 2 selected by the optical detection system 16 during detection are respectively adjacent fingerprint ridges and fingerprint valleys on the three-dimensional finger. The part is the fingerprint ridge and fingerprint valley that are closest to each other. The first distance A1B2 corresponding to the fingerprint ridge A and the fingerprint valley B on the first image and the corresponding second distance A3B4 on the second image may range from 100 μm to 300 μm. This value range may be based on The optical parameters of the lens module 160 and the adjustment of the positional relationship between the lens module 160 , the image sensor 162 and the protective layer 12 change.

Optionally, in some other embodiments, the first feature point A and the second feature point B of the external object 2 selected by the optical detection system 16 during detection can also be non-adjacent fingerprint ridges on the three-dimensional finger. Department and fingerprint valley.

Optionally, in this embodiment, the first lens 1601 and the second lens 1602 are respectively a pair of adjacent small lenses 1600 among the plurality of small lenses 1600, so that the first lens 1601 The first field of view range FOV1 and the second field of view range FOV2 of the second lens 1602 have overlapping fields of view ranges that overlap with each other. The proportion of the overlapping field of view range in the first field of view range FOV1 and the second field of view range FOV2 exceeds a preset ratio value, for example, greater than or equal to 30%.

Optionally, in some other embodiments, one or more small lenses 1600 may be spaced between the first lens 1601 and the second lens 1602, as long as the first viewing angle of the first lens 1601 is satisfied. The overlapping field of view range can be formed between the field range FOV1 and the second field of view range FOV2 of the second lens 1602, and the proportion of the overlapping field of view range meets the aforementioned requirements.

The optical detection system 16 also includes a processing module. The processing module is used to compare the difference between the first image formed by the first lens 1601 and the second image formed by the second lens 1602 of the external object 2 within the overlapping field of view, And based on the comparison result, it is determined whether the external object 2 is a three-dimensional object or a planar object. Wherein, if the difference between the first image and the second image of the external object 2 is greater than or equal to the preset threshold, then the external object 2 is determined to be a three-dimensional object; if the difference between the first image and the second image of the external object 2 If the difference between the two images is less than the preset threshold, it is determined that the external object 2 is a planar object.

Specifically, as shown in FIG. 4 , the external object 2 includes a first feature point A and a second feature point B. The distance between the first imaging point A1 and the second imaging point B2 corresponding to the first feature point A and the second feature point B on the first image is a first distance A1B2. The distance between the third imaging point A3 and the fourth imaging point B4 corresponding to the first feature point A and the second feature point B on the second image is the second distance A3B4. Optionally, in some embodiments, the difference between the first image and the second image may be the difference between the first distance A1B2 and the second distance A3B4, and the preset threshold is the first distance A1B2 and the second distance A3B4. The threshold for the difference between the spacing and the second spacing.

The difference between the grayscale values of the first imaging point A1 and the second imaging point B2 corresponding to the first feature point A and the second feature point B on the first image is a first grayscale difference. The difference in grayscale values between the third imaging point A3 and the fourth imaging point B4 corresponding to the first feature point A and the second feature point B on the second image is a second grayscale difference. Optionally, in some embodiments, the difference between the first image and the second image is the difference between the first grayscale difference and the second grayscale difference, and the preset threshold is the third grayscale difference. The threshold value of the difference between the first gray level difference and the second gray level difference.

Optionally, in this embodiment, the external object 2 is the user's finger, the first feature point A is the fingerprint ridge of the finger, and the second feature point B is the fingerprint valley of the finger. Optionally, in some other embodiments, the external object 2 may also be other three-dimensional objects, and the first feature point A and the second feature point B may be points on the external object 2 that are respectively located on different planes.

It can be understood that, before comparing the first image and the second image, the processing module 161 can determine the first feature point A and the second image by performing feature matching on the first image and the second image. The corresponding image points of the second feature point B on the first image and the second image respectively.

Optionally, in this embodiment, the processing module 161 determines whether the external object is three-dimensional based on the difference between the images of the external object 2 acquired from different viewing angles by two imaging modules with mutually overlapping fields of view. It can be understood that in some other embodiments, the processing module 161 can also acquire multiple images of the external object 2 located within the overlapping fields of view from different viewing angles through two or more imaging modules with overlapping fields of view. image, and perform statistical analysis on the differences between the acquired images of the external object 2, such as mean difference analysis, standard deviation analysis, etc., and then compare them with the preset difference threshold to determine the external Whether object 2 is three-dimensional.

Optionally, in this embodiment, the processing module 161 may also be used to compare the first image and/or the second image of the external object 2 with a pre-stored template of the external object 2, and based on the comparison The result identifies the identity of said external object 2.

It can be understood that, in some embodiments, the processing module 161 performs the above comparison and identification after determining that the external object 2 is a three-dimensional object. The processing module 161 does not perform subsequent comparison and identification after determining that the external object 2 is a planar object, thereby saving energy consumption of the optical detection system 16 .

Optionally, in some embodiments, the processing module may be connected to the image sensor 162 to receive image data converted by the image sensor 162 according to the image of the external object 2 formed by the lens module 160 . Optionally, in other embodiments, the optical detection system may also include a memory 18, and the image data converted by the image sensor 162 according to the image of the external object 2 may be stored in the memory 18, so The processing module 161 obtains the image data of the external object 2 from the memory 18 .

Optionally, in some embodiments, the processing module 161 may be firmware solidified in the memory 18 or a computer software code stored in the memory 18 . The processing module 161 is executed by a corresponding one or more processors (not shown) to control related components to implement corresponding functions. The processor may be, for example, but not limited to, an application processor (Application Processor, AP), a central processing unit (CPU), a microprocessor (MCU), etc. The memory 18 includes, but is not limited to, flash memory (Flash Memory), electrically erasable programmable read only memory (EEPROM), programmable read only memory (PROM), and hard disks. The memory 18 can be used to store the external object 2 template for identifying the identity of the external object 2, various preset thresholds, the image data of the external object 2 acquired by the image sensor 162, and the comparison and judgment process. Intermediate data generated, etc.

Optionally, in some embodiments, the processor 17 and/or the memory 18 may be integrated on the same substrate as the image sensor 162 . Optionally, in some other embodiments, the processor 17 and/or the memory 18 may also be provided on the host of the electronic device 1, such as the main circuit board of a mobile phone.

Optionally, in some embodiments, the function of the processing module 161 can also be implemented by hardware, for example, by any one of the following technologies or a combination thereof: having a module for implementing logical functions on the data signal. Discrete logic circuits of logic gates, application specific integrated circuits with suitable combinational logic gates, programmable gate arrays (PGA), field programmable gate arrays (FPGA), etc. It can be understood that the above-mentioned hardware used to implement the function of the processing module 161 can be integrated on the same substrate as the image sensor 162 , or can be provided on the host of the electronic device 1 .

Compared with the prior art, the optical detection system 16 of the present application determines whether the external object 2 is a three-dimensional object by comparing whether there are differences due to parallax between the images of the external object 2 acquired from different viewing angles, which can effectively prevent Criminals use planar imitations printed with images of external objects 2 to attack the recognition function of the optical detection system 16 , thereby improving the security of the electronic device 1 .

As shown in Figure 6, Figure 6 is a partial cross-sectional schematic diagram of the optical detection system 16b according to the second embodiment of the present application. The structural difference between the optical detection system 16b and the optical detection system 16a of the first embodiment is that the first imaging module 166 and the second imaging module 168 of the optical detection system 16b are independent optical imaging modules respectively. The first imaging module 166 includes a first lens 1601 and a first image sensor 162 . The second imaging module 168 includes a second lens 1602 and a second image sensor 162 . The optical detection system 16b does not use the structure of the small lens 1600 array to image the external object 2, but instead uses the independent first lens 1601 and the second lens 1602 to image the external object 2 respectively. The first lens 1601 and the second lens 1602 are respectively imaged on the first image sensor 162a and the second image sensor 162b that are independent of each other, rather than on different areas of the same image sensor 162.

Optionally, in some embodiments, the optical detection system 16b may also include more than two independent imaging modules with overlapping fields of view, and obtain multiple images of the external object 2 located within the overlapping fields of view from different viewing angles. images. The processing module 161 (refer to Figure 5) can perform statistical analysis on the differences between the acquired images of the external object 2, such as mean difference analysis, standard deviation analysis, etc., and then compare them with the preset differences. The threshold is compared to determine whether the external object 2 is three-dimensional.

It should be noted that those skilled in the art can understand that part or all of the embodiments of the present application, as well as modifications, replacements, changes, disassemblies, combinations, Extensions, etc. should be considered to be covered by the creative ideas of this application and belong to the protection scope of this application.

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 present application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Additionally, when a particular feature or structure is described in connection with any embodiment, it is claimed that it is within the skill of those skilled in the art to implement such feature or structure in conjunction with other embodiments of these embodiments.

"Length", "width", "top", "bottom", "left", "right", "front", "back", "back", "front", "vertical" that may appear in this application specification ", "horizontal", "top", "bottom", "inside", "outside", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the present application and The simplified description is not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be construed as a limitation on the present application. Similar reference numbers and letters refer to similar items in the drawings, so that once an item is defined in one drawing, it does not need further definition or explanation in subsequent drawings. Meanwhile, in the description of the present application, the terms "first", "second", etc. are only used to differentiate the description and cannot be understood as indicating or implying relative importance. In the description of this application, "a plurality" or "a plurality" means at least two or two, unless otherwise expressly and specifically limited. In the description of this application, it should also be noted that, unless otherwise clearly stipulated and limited, "setting", "installation" and "connection" should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection. , or integrally connected; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood on a case-by-case basis.

The above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person familiar with the technical field can easily think of changes or replacements within the technical scope disclosed in the present application. should be covered by the protection scope of this application. The terms used in the claims should not be construed as limiting the application to the specific embodiments disclosed in the specification. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims (7)

1. An optical inspection system for inspecting an external object, comprising:

a first lens having a first field of view for imaging an external object within the first field of view;

a second lens having a second field of view range for imaging an external object within the second field of view range, the first field of view range and the second field of view range at least partially overlapping, defining a portion of the first field of view range and the second field of view range overlapping each other as an overlapping field of view range;

the lens module is positioned below the display screen and comprises a plurality of small lenses which are arranged in an array, and the first lens and the second lens are respectively one of the small lenses;

The image sensor is positioned below the first lens and the second lens, and comprises a plurality of first photosensitive units and a plurality of second photosensitive units, wherein the first photosensitive units are used for receiving imaging light converged by the first lens and converting the imaging light into corresponding electric signals, and the second photosensitive units are used for receiving the light converged by the second lens and converting the imaging light into corresponding electric signals; and

the processing module is used for comparing differences between a first image formed by the external object through the first lens and a second image formed by the second lens in the overlapping view field range, and judging that the external object is a three-dimensional object when the differences are larger than or equal to a preset threshold value;

wherein the difference between the first image and the second image comprises:

the external object comprises a first characteristic point and a second characteristic point, the distance between the first characteristic point and the second characteristic point on the corresponding image points of the first image is a first interval, the distance between the first characteristic point and the second characteristic point on the corresponding image points of the second image is a second interval, the difference between the first image and the second image is the difference value between the first interval and the second interval, and the preset threshold value is the threshold value of the difference value between the first interval and the second interval;

Or the external object comprises a first characteristic point and a second characteristic point, the difference of gray values of corresponding image points of the first characteristic point and the second characteristic point on the first image is a first gray level difference, the difference of gray values of corresponding image points of the first characteristic point and the second characteristic point on the second image is a second gray level difference, the difference between the first image and the second image is the difference of the first gray level difference and the second gray level difference, and the preset threshold is the threshold of the difference of the first gray level difference and the second gray level difference.

2. The optical detection system of claim 1, wherein the external object is a portion of a fingerprint trace of a user's finger within the overlapping field of view, the first feature point is a fingerprint ridge, and the second feature point is a fingerprint valley.

3. The optical detection system according to claim 1, wherein the first feature point and the second feature point are formed on the first image and the second image at a pitch ranging from 100 μm to 300 μm, respectively.

4. The optical detection system of claim 1, wherein the overlapping field of view range in the first field of view range and the second field of view range is greater than or equal to 30%.

5. The optical detection system of claim 1, wherein the display screen is an actively illuminated display screen, light emitted by the display screen being usable to illuminate an external object to form the first image and/or the second image; or alternatively

The display screen is a passive luminous display module, and the optical detection system under the display screen further comprises an excitation light source for providing light required by detection.

6. The optical detection system according to claim 1, wherein the processing module is further configured to compare the first image and/or the second image of the external object with a pre-stored external object template, and identify the identity of the external object according to the comparison result.

7. An electronic device comprising an optical detection system according to any one of claims 1-6.