Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In modern information society, there are a large number of scenes that need the user to carry out fingerprint authentication in daily life, have greatly promoted people's convenience of life. In the prior art, whether a user is himself or not is often verified through fingerprint image information, but the technologies can be cracked through stickers, 3D printing models and the like, and the safety of the technologies cannot be guaranteed. Therefore, in the embodiment of the invention, a fingerprint living body identification device is provided for determining whether an object to be detected is a living body fingerprint of a user.
Fig. 1a is a schematic structural diagram of a fingerprint living body identification apparatus according to an embodiment of the present invention, and fig. 1b is a top view of a fingerprint living body identification apparatus according to an embodiment of the present invention. As shown in fig. 1a and 1b, the fingerprint biometric apparatus includes: the light source module 200, the spectral imaging chip 100, the signal processing circuit module, and the recognition module 400. The signal processing circuit module is not separately shown in fig. 1a and 1b, because the signal processing circuit module may be integrated in the spectral imaging chip 100, or may be a part independent of the spectral imaging chip 100 in the fingerprint biometric apparatus, for example, a computer, etc., which is not particularly limited in the embodiment of the present invention. The display screen 300 may include a cover glass, a touch module, and a display module. The display screen 300 is provided with a fingerprint detection area 301, and an object 500 to be detected can be placed in the fingerprint detection area 301. The object 500 to be detected may be a living fingerprint of the user himself, a living fingerprint of another person, a sticker carrying fingerprint information, a 3D print model, or the like, which is not particularly limited in the embodiment of the present invention.
The light source module 200 is used for illuminating the object 500 to be detected in the fingerprint detection area, and the light source module 200 may be a separate part independent of the display screen, such as an LED light source, or a laser light source with a certain wavelength, such as 940nm laser, or the like. In addition, the light source module may be integrated in the display screen 300, and is a part of a self-luminous display module in the display screen 300, which is not particularly limited in the embodiment of the present invention. The upper surface of the light source module 200 may be provided with a lens for converging the light beam emitted from the light source module.
After being reflected by the object 500 to be detected, a target beam can be obtained, and the target beam is incident on the spectral imaging chip 100. After the target beam irradiates, the pixel point corresponding to each modulation unit in the light modulation layer of the spectral imaging chip 100 has spectrum information, and the pixel point corresponding to each non-modulation unit in the light modulation layer has light intensity information. The spectrum information refers to light intensity information corresponding to light with different wavelengths at the pixel point corresponding to each modulation unit. The light modulation effect of different modulation units on different wavelengths may be the same or different, and may be set according to needs, which is not particularly limited in the embodiment of the present invention. Thus, the spectral imaging chip 100 can determine spectral information as well as light intensity information. And then the signal processing circuit module respectively determines the spectrum information and the image information of the object to be detected 500 according to the spectrum information and the light intensity information. When the signal processing circuit module is integrated within the spectral imaging chip, it can be considered that the spectral imaging chip has a function of determining the spectral information and the image information of the object to be detected 500.
In the fingerprint living body recognition device, the vertical distance from the light source module to the display screen can be 0mm-30mm, and correspondingly, the vertical distance from the light source module to the spectrum imaging chip can be 0mm-30 mm. The vertical distance from the light source module to the display screen can be 0.5mm-20mm, and correspondingly, the vertical distance from the light source module to the spectrum imaging chip can be 0.5mm-20 mm. It should be noted that, in the respective embodiments, the spectral imaging chip is attached to the display screen by an adhesive, and even if the spectral imaging chip is provided with the adhesive between the spectral imaging chip and the display screen, it is understood that the distance is 0mm, that is, errors caused by assembly, fixing, etc. do not affect the starting point of the present invention.
The identification module 400 is electrically connected to the signal processing circuit module, and the identification module 400 can acquire the spectral information and the image information of the object 500 to be detected determined by the signal processing circuit module, and identify whether the object 500 to be detected is a living fingerprint of the target user according to the spectral information and the image information of the object 500 to be detected. The fingerprint image information and fingerprint spectrum information of the target user may be stored in advance in the recognition module 400, first, the image information of the object 500 to be detected determined by the spectrum imaging chip 100 may be compared with the fingerprint image information of the target user stored in advance in the recognition module 400, and if the two are the same or have an error within a preset range, it may be determined that the object to be detected is an object belonging to the target user. Then, the spectrum information of the object 500 to be detected determined by the spectrum imaging chip 100 is compared with the fingerprint spectrum information stored in advance in the recognition model 400, and if the spectrum information and the fingerprint spectrum information are the same or have the error within the preset range, the living fingerprint of the target user can be determined.
The fingerprint living body identification device provided by the embodiment of the invention comprises a display screen, a light source module, a spectrum imaging chip, a signal processing circuit module and an identification module, wherein a fingerprint detection area is arranged on the display screen, a target light beam obtained by irradiating an object to be detected in the fingerprint detection area through the light source module and reflecting the object to be detected is incident on the spectrum imaging chip, the spectrum imaging chip determines spectrum information and light intensity information, the signal processing circuit module determines spectrum information and image information of the object to be detected, and finally the identification module identifies whether the object to be detected is a living body fingerprint of a target user according to the spectrum information and the image information of the object to be detected. Compared with the existing fingerprint identification device, the fingerprint living body identification device provided by the embodiment of the invention can realize fingerprint living body identification, is beneficial to improving the stability of device performance, reduces the volume, weight and cost of a spectrum device, and greatly improves the anti-counterfeiting capacity of a fingerprint identification system. In addition, compared with the traditional image sensor, the spectrum imaging chip adopted in the embodiment of the invention can obtain spectrum information without influencing the spatial resolution and imaging quality of the formed image, and is convenient for grasping more comprehensive information of the object to be detected. In addition, because the spectrum information of the object to be detected can be used for uniquely identifying the object to be detected, whether the object to be detected is the living fingerprint of the target user can be judged through the spectrum information of the object to be detected, the detection accuracy can be improved, and the fingerprint identity verification realized through the fingerprint living identification device is safer and more reliable.
On the basis of the above embodiment, the fingerprint living body identification device provided in the embodiment of the present invention, the spectral imaging chip includes: a light modulation layer and an image sensing layer which are sequentially laminated along the thickness direction; at least one modulation unit and at least one non-modulation unit are distributed along the surface of the light modulation layer; the image sensing layer is distributed with a plurality of sensing units along the surface, and each modulating unit and each non-modulating unit respectively correspond to at least one sensing unit along the thickness direction; the signal processing circuit module is electrically connected with the sensing unit.
Specifically, fig. 2 is a schematic structural diagram of a spectral imaging chip in the fingerprint living body recognition device according to the embodiment of the present invention. As shown in fig. 2, the spectral imaging chip 100 may include: the light modulation layer 110, the image sensing layer 120 and the signal processing circuit module 130, i.e. the signal processing circuit module 130 in the embodiment of the invention, are integrated in the spectral imaging chip 100. The light modulation layer 110, the image sensing layer 120, and the signal processing circuit module 130 are sequentially stacked in the thickness direction. The light modulation layer 110 has at least one modulation unit 1101 and at least one non-modulation unit 1102 distributed along the surface. The image sensing layer 120 has a plurality of sensing units 1201 distributed along the surface, and each modulating unit 1101 and each non-modulating unit 1102 respectively correspond to at least one sensing unit 1201 along the thickness direction, and at least one modulating unit 1101 and a plurality of non-modulating units 1102 around the modulating unit 1101 and the corresponding sensing units 120 form a pixel point of the spectral imaging chip 100. The signal processing circuit module 130 is electrically connected to the sensing unit 1201 on the image sensing layer 120, and the signal processing circuit module 130 is used for determining image information and spectrum information of an object to be detected.
The thickness of the light modulation layer 110 is 60nm to 1200nm, and the light modulation layer 110 may be directly prepared on the image sensing layer 120. Specifically, one or more layers of materials are directly grown on the image sensing layer 120 and then etched to prepare a modulating unit, or the modulating unit is directly etched on the image sensing layer 120 to obtain the light modulating layer 110. The image sensing layer 120 may be specifically a CIS wafer, and each sensing unit in the image sensing layer 120 corresponds to one pixel in the CIS wafer, for detecting the light beam passing through the light modulation layer. The light modulation layer is directly monolithically integrated on the CIS wafer from the wafer level, and the preparation of the spectrum imaging chip can be completed by utilizing the one-time flow sheet of the CMOS process.
Each modulating unit 1101 may be a micro-nano structure unit for modulating the target beam, and each non-modulating unit 1102 has no modulating capability and cannot modulate the target beam. Each non-modulating cell 1102 may be either a blank cell or a solid cell that does not have modulating capability but can directly transmit the target beam and is of the same material as the modulating cell. Each modulation unit 1101 on the light modulation layer 110 may be directly prepared on the surface of a photosensitive area of the CIS wafer, and an area of the CIS wafer where no modulation unit is prepared corresponds to a non-modulation unit on the light modulation layer, which is also a conventional RGB or black and white pixel. Because the light modulation layer of the spectrum imaging chip comprises the modulation units and the non-modulation units, the spectrum information of the pixel point corresponding to each modulation unit, namely the spectrum information modulated by each modulation unit and detected by the corresponding sensing unit, can be obtained, and the light intensity information of the pixel point corresponding to each non-modulation unit, namely the light intensity information modulated by each non-modulation unit and detected by the corresponding sensing unit can be obtained.
The signal processing circuit module 130 can determine the spectrum information of the object to be detected according to the spectrum information of the pixel point corresponding to each modulation unit after the irradiation of the target beam, specifically, the spectrum information obtained by each modulation unit is encoded onto the corresponding sensing unit of the CIS wafer, and then the spectrum information is obtained by reconstructing by adopting a unit array response processing method. The spectrum reconstruction algorithm can specifically include, but is not limited to, a least square method, a non-negative least square method, an analog annealing method, a Tikhonov regularization method, a truncated singular value decomposition method, a sparse optimization method and the like.
Because the spectrum information of the pixel point corresponding to each modulation unit cannot be used for determining the image information of the object to be detected, the image information of the object to be detected needs to be determined according to the light intensity information of the pixel point corresponding to each non-modulation unit after the irradiation of the target light beam. The specific mode can ignore the light intensity information of the pixel points corresponding to each modulation unit, and only the light intensity information of the pixel points corresponding to all non-modulation units is adopted to determine the image information of the object to be detected; the light intensity information of the pixel points corresponding to each modulating unit can be determined through the light intensity information of the pixel points corresponding to each non-modulating unit, and then the image information of the object to be detected can be determined by combining the light intensity information of the pixel points corresponding to all the non-modulating units. This is not particularly limited in the embodiments of the present invention.
On the basis of the above embodiment, the fingerprint living body identification apparatus provided in the embodiment of the present invention, the signal processing circuit module is specifically configured to:
determining fitting light intensity information of the pixel points corresponding to each modulation unit based on the light intensity information of the pixel points corresponding to a plurality of non-modulation units around each modulation unit after the target light beam is irradiated;
And determining the image information of the object to be detected based on the fitting light intensity information of the pixel points corresponding to each modulation unit and the light intensity information of the pixel points corresponding to each non-modulation unit.
Specifically, when determining the image information of the object to be detected, the signal processing circuit module in the embodiment of the invention may first determine the fitting light intensity information of the pixel points corresponding to each modulation unit according to the light intensity information of the pixel points corresponding to at least one non-modulation unit around each modulation unit after the irradiation of the target light beam. The surrounding of each modulation unit refers to a position of which the distance from the modulation unit is within a preset range, and the preset range can be set according to needs, which is not particularly limited in the embodiment of the present invention. For example, 8 positions such as left, upper right, lower left, and lower left, which are closest to the modulation unit, may be around each modulation unit, or a position which is next closest to the modulation unit may be around each modulation unit. The number of non-modulation cells around each modulation cell is related to the structure of the light modulation layer, and the light modulation layer is generally rectangular in structure, and the position closest to the modulation cell is exemplified around each modulation cell, so that there are 3 cells around each cell at the vertex position, 5 cells around each cell at other edge positions except the vertex position, and 8 cells around each cell at other edge positions. If the structure of the light modulation layer is as shown in fig. 3, there are at most 5 non-modulation units around each modulation unit, and at least 3 non-modulation units; if the structure of the light modulation layer is as shown in fig. 4, there are at most 6 non-modulation units around each modulation unit, and at least 0 non-modulation units; if the structure of the light modulation layer is as shown in fig. 5, there are at most 4 non-modulation units around each modulation unit, and at least 0 non-modulation units; if the structure of the light modulation layer is as shown in fig. 6, there are 8 non-modulation units around each modulation unit.
Taking the structure of the light modulation layer shown in fig. 6 as an example, the light intensity information of the pixel points corresponding to at least one non-modulation unit around each modulation unit can be fitted, so as to determine the fitting light intensity information of the pixel points corresponding to each modulation unit. The fitting method may be an arithmetic average, a weighted average, or a method of selecting a median of the light intensity information, which is not particularly limited in the embodiment of the present invention.
Then, according to the fitting light intensity information of the pixel points corresponding to each modulation unit and the light intensity information of the pixel points corresponding to each non-modulation unit, the image information of the object to be detected can be determined. The image information is complete image information, and comprises light intensity information of each pixel point.
In the embodiment of the invention, the fitting light intensity information of the pixel points corresponding to each modulation unit is determined through the light intensity information of the pixel points corresponding to at least one non-modulation unit around each modulation unit after the irradiation of the target light beam, so that the determined image information of the object to be detected is complete image information according to the fitting light intensity information of the pixel points corresponding to each modulation unit and the light intensity information of the pixel points corresponding to each non-modulation unit, thereby ensuring the integrity of the image and not influencing the integral imaging.
On the basis of the above embodiment, the fingerprint living body identification apparatus provided in the embodiment of the present invention, the signal processing circuit module is specifically configured to:
And filtering the light intensity information of the pixel points corresponding to the non-modulation units around any modulation unit based on a smooth filtering method to obtain fitting light intensity information of the pixel points corresponding to any modulation unit.
Specifically, in the embodiment of the invention, when determining the fitting light intensity information of the pixel point corresponding to each modulation unit, the fitting light intensity information can be specifically realized by a smoothing filtering method. The smoothing filtering method may include median filtering, smoothing filtering, gaussian filtering, and the like.
For median filtering, if the size of the filtering window is 3*3 pixels, the light intensity information of the pixel corresponding to any modulation unit a is:
f(x,y)＝median[f(x-1,y-1),f(x,y-1),f(x+1,y-1),f(x-1,y),f(x+1,y),f(x-1,y+1),f(x,y+1),f(x+1,y+1)]
Wherein media represents median operation, f (x, y) is light intensity information of a pixel point corresponding to the modulation unit A, and (x, y) is coordinate value of the pixel point corresponding to the modulation unit A; f (x-1, y-1) is the light intensity information of the pixel point corresponding to the non-modulation unit at the lower left of the modulation unit A, and if the lower left of the modulation unit A is not the non-modulation unit, the value is 0; f (x, y-1) is the light intensity information of the pixel point corresponding to the non-modulation unit below the modulation unit A, and if the non-modulation unit below the modulation unit A is not the modulation unit, the value is 0; f (x+1, y-1) is a pixel point corresponding to a non-modulation unit at the lower right of the modulation unit A, and if the lower right of the modulation unit A is not the non-modulation unit, the value is 0; f (x-1, y) is a pixel point corresponding to a non-modulation unit on the left of the modulation unit A, and if the modulation unit A is not a non-modulation unit on the left, the value is 0; f (x+1, y) is a pixel point corresponding to a non-modulation unit on the right of the modulation unit a, and if the modulation unit a is not a non-modulation unit on the right, the value is 0; f (x-1, y+1) is a pixel point corresponding to a non-modulation unit at the upper left of the modulation unit A, and if the upper left of the modulation unit A is not the non-modulation unit, the value is 0; f (x, y+1) is a pixel point corresponding to a non-modulation unit above the modulation unit A, and if the non-modulation unit above the modulation unit A is not the modulation unit, the value is 0; f (x+1, y+1) is a pixel point corresponding to a non-modulation unit at the upper right of the modulation unit a, and if the upper right of the modulation unit a is not a non-modulation unit, the value is 0.
For the mean value filtering, if the size of the filtering window is 3*3 pixels, the light intensity information of the pixel corresponding to any modulation unit A is:
f(x,y)＝[f(x-1,y-1)+f(x,y-1)+f(x+1,y-1)+f(x-1,y)+f(x+1,y)+f(x-1,y+1)+f(x,y+1)+f(x+1,y+1)]/8
for gaussian filtering, if the size of the filtering window is 3*3 pixels, the light intensity information of the pixel corresponding to any modulation unit a is:
f(x,y)＝0.111*[f(x-1,y-1)+f(x+1,y-1)+f(x-1,y+1)+f(x+1,y+1)]+0.139*[f(x,y-1)+f(x-1,y)+f(x+1,y)+f(x,y+1)]
Wherein, 0.11 and 0.139 are the weights of the light intensity information of the corresponding pixel points respectively.
On the basis of the foregoing embodiments, the fingerprint living body identification apparatus provided in the embodiment of the present invention, the signal processing circuit module is specifically configured to:
inputting an initial image obtained based on the light intensity information of the pixel points corresponding to all the non-modulation units after the target light beam is irradiated into a fitting model to obtain the image information of the object to be detected output by the fitting model;
The fitting model is constructed based on an antagonistic neural network, and is obtained by training based on a blank sample image with blank pixels and a complete sample image label without the blank pixels, corresponding to the blank sample image.
Specifically, in the embodiment of the invention, when determining the image information of the object to be detected, the method can be realized by a machine learning method such as an antagonistic neural network. In the embodiment of the invention, a fitting model is built by antagonizing a neural network, and training is carried out on the fitting model through a blank sample image with blank pixels and a complete sample image label without blank pixels corresponding to the blank sample image. And finally, inputting an initial image obtained based on the light intensity information of the pixel points corresponding to all the non-modulation units after the target light beam is irradiated into a fitting model to obtain the image information of the object to be detected output by the fitting model. The complete sample image label refers to an actual complete sample image corresponding to the empty sample image.
In the embodiment of the invention, the fitting model constructed based on the antagonistic neural network is introduced, so that the image information of the object to be detected can be determined more quickly and accurately.
On the basis of the above embodiment, the fingerprint living body identification apparatus provided in the embodiment of the present invention further includes: fitting model training module for:
Training the generator in the countermeasure neural network based on the vacancy sample image and the complete sample image label corresponding to the vacancy sample image, and performing competition authentication on the trained generator based on the discriminator in the countermeasure neural network;
and taking the trained generator as the fitting model.
Specifically, the antagonistic neural network includes a generator and a discriminator, the generator takes a blank sample image as input, and generates a complete sample image corresponding to the blank sample image as output. The discriminator takes as input a plurality of complete sample images including complete sample image tags and complete sample images generated by the generator. During training, the generator and discriminator compete with each other. The object of the generator is to output the complete sample image with high discrimination score through the discriminator as much as possible, and the object of the discriminator is to make the label of the complete sample image with high score as much as possible and make the score of the complete sample image output by the generator as low as possible. After training, a generator is obtained, and the generator obtained through training is used as a fitting model.
On the basis of the above embodiment, in the fingerprint living body identification device provided in the embodiment of the present invention, each modulation unit in the light modulation layer includes a plurality of modulation subunits, and each modulation subunit is in a hole structure or a columnar structure.
Specifically, in an embodiment of the present invention, each modulation unit in the light modulation layer includes a plurality of modulation subunits distributed along the surface. The modulation subunit may have a hole structure or a columnar structure. The modulation subunits that are in a hole-like structure may be referred to as modulation holes and the modulation subunits that are in a columnar structure may be referred to as modulation columns. It should be noted that the same modulation unit may include only the modulation hole or the modulation column, or may include both the modulation hole and the modulation column, so that the modulation unit including the modulation hole may be referred to as Kong Diaozhi units, and the modulation unit including the modulation column may be referred to as a column modulation unit.
Preferably, the light modulation layer may be silicon nitride having a thickness of 200nm to 500 nm. The light modulation layer may have 1000 to 250000 cells distributed thereon, each cell having a size of 100 μm2～40000μm2. Wherein the modulation units account for 10% of the total unit number, and the rest 90% are non-modulation units.
The light modulation layer may also be silicon with a thickness of 100-400nm as a preferred solution. The light modulation layer may have 1000 to 250000 cells distributed thereon, each cell having a size of 100 μm2～40000μm2. Wherein the modulation units account for 15% of the total unit number, and the rest 85% are non-modulation units.
Based on the foregoing embodiments, in the fingerprint living body identification apparatus provided in the embodiments of the present invention, the modulation unit in the optical modulation layer may be a micro-nano structural unit, and is obtained by etching. The structure of the light modulation layer is shown in fig. 3-6. In fig. 3, a plurality of different modulation units are distributed at the edge position of the light modulation layer, each modulation unit may correspond to one or more sensing units, the modulation units may occupy or not occupy the edge position, may be continuously or discontinuously distributed, and may be located at any edge position, the rest positions of the light modulation layer are non-modulation units, i.e. no modulation units are engraved, and are blank units, and the target light beam may be directly transmitted to the RGB or black and white pixels of the CIS wafer below the light modulation layer. Under each cell (including modulating cells and non-modulating cells) of the light modulating layer there is a corresponding sensing cell. Each modulation unit in the light modulation layer has different modulation effects on light with different wavelengths, the modulation modes of the input spectrum between the modulation units can be the same or different, and the different modulation modes can include but are not limited to scattering, absorption, transmission, reflection, interference, excimer, resonance enhancement and other effects, and the final effect of the modulation effects is that the transmission spectrum of the light with different wavelengths after passing through the modulation units is different. After the light is modulated by the modulation unit, the light intensity information is detected by the corresponding sensing unit below the modulation unit. Each unit and the sensing unit below the unit form a pixel point. The intensity distribution of each wavelength on a pixel point can be obtained through an algorithm.
In fig. 4, a plurality of different modulation units are distributed at the edge position and the middle position of the light modulation layer, each modulation unit can correspond to one or more sensing units, the modulation units can be located at any edge position or middle position, can be distributed continuously or discontinuously, and can be selected at random. Each modulation unit may be an array of a plurality of identical modulation subunits or an array of a plurality of different modulation subunits.
In fig. 5, every four modulation units on the optical modulation layer are a group of modulation units, every four non-modulation units are a group of non-modulation units, and every group of modulation units is distributed at intervals with every group of non-modulation units.
In fig. 6, 8 positions around each modulation unit on the light modulation layer are all non-modulation units, and no other modulation units exist.
On the basis of the above embodiment, in the fingerprint living body identification apparatus provided in the embodiment of the present invention, the hole cross-sectional shapes of different modulation subunits of the hole-like structure in each modulation unit are not completely the same; and/or the number of the groups of groups,
The structural parameters of the different modulation subunits of each modulation unit, which are the porous structures, are not identical.
Specifically, in the embodiment of the present invention, the hole cross-sectional shapes of different modulation holes in each modulation unit may be the same, may be completely different, or may be partially the same or partially different. That is, all modulation apertures within the same modulation unit have the same or different aperture cross-sectional shapes. The structural parameters of the modulation apertures in each modulation unit may also be identical, may also be completely different or may be partially identical and partially different. Whether the hole cross-sectional shapes of different modulation holes in each modulation unit are the same does not affect whether the structural parameters are the same. The cross-sectional shape of the hole includes a circle, an ellipse, a cross, a regular polygon, a star, or a rectangle. The structural parameters may include, but are not limited to, parameters such as the period, radius, side length, duty cycle, thickness, major axis length, minor axis length, rotation angle, or number of angles of the modulation aperture in each modulation unit. The modulation holes can be arranged row by row or column by column according to a preset periodic sequence, or arranged in an array according to a gradual change sequence of the size of the structural parameters.
Since the modulation effect is affected by the different cross-sectional shapes and/or different structural parameters of the modulation holes in the modulation unit, the modulation effect can be changed by changing the shape of the modulation holes in the modulation unit. The change in the structural parameter may be a change in the structural parameter of any combination of the above.
The period of the modulation hole in each column modulation unit can be value between 50nm and 800nm, and the duty ratio can be value between 5% and 95%. The period of the modulation hole can be also between 80nm and 600nm, and the duty ratio can be also between 10% and 90%.
The different modulation units have different modulation effects on the spectrum, which may include, but are not limited to, scattering, absorption, transmission, reflection, interference, surface plasmons, resonance, etc. By changing the structural parameters (including but not limited to one of the parameters such as period, radius, side length, duty cycle and thickness or any combination of the parameters) and arrangement mode of the modulation holes in the column modulation unit, the modulation effect can be changed, and the sensitivity to the difference between different spectrums can be improved by increasing the number of modulation columns.
On the basis of the above embodiments, in the fingerprint living body identification apparatus provided in the embodiment of the present invention, the structural shape and the column height of different modulation subunits of the columnar structure in each modulation unit are the same, and the arrangement of all the modulation subunits in each modulation unit has C4 symmetry.
Specifically, each column modulation unit comprises a plurality of modulation columns, all the modulation columns in the same column modulation unit have the same structural shape, and each modulation column is arranged row by row or column by column according to a preset cycle sequence and has C4 symmetry. All the modulation columns in the same column modulation unit have the same height, and the modulation column heights of different column modulation units can be the same or different. The structural parameters of the modulation column may include height, longitudinal section structural parameters, cross section structural parameters, and the like. The shape of the modulation columns may be as shown in fig. 7, including but not limited to cylinders, cubes, cones, bells, etc. The longitudinal cross-sectional shape of the modulation column may be as shown in fig. 8, including but not limited to rectangular, trapezoidal, triangular, bell-shaped, etc. The cross-sectional shape of the modulation column includes rectangular, circular, etc.
The height of the modulation column can take a value between 100nm and 400 nm. For cylindrical modulation columns, the diameter of the modulation column can take on values between 10nm and 300 nm. For a cube modulation column, the cross section of the modulation column can be square or rectangular, and the side length can be between 10nm and 400 nm. For a truncated cone-shaped modulation column, the diameters of the two circular sections of the modulation column can be between 10nm and 400 nm. For conical modulation columns, the diameter of the bottom circle of the modulation column can take on values between 10nm and 400 nm. For a bell-shaped modulation column, the diameter of the bottom circle of the modulation column can take a value between 10nm and 400 nm.
On the basis of the above embodiment, in the fingerprint living body identification device provided in the embodiment of the present invention, the modulation subunit of the columnar structure is integrally formed, or is formed by stacking multiple layers of modulation columns.
Specifically, as shown in fig. 9, the spectral imaging chip includes: the light modulation layer 110, the image sensing layer 120 and the signal processing circuit module 130, i.e. the signal processing circuit module 130 in the embodiment of the invention, are integrated in the spectral imaging chip 100. The modulation unit of the light modulation layer 110 includes a modulation column, and the modulation column is integrally formed. As shown in fig. 10, the modulation columns may also be formed by stacking multiple layers of sub-modulation columns, each layer of sub-modulation columns may have the same or different structural shape, each layer of sub-modulation columns may be a cube, a cylinder, etc., each layer of sub-modulation columns may have the same or different materials, and may be any one of metal or medium. In fig. 10, the modulation column is formed by stacking a plurality of layers of rectangular parallelepiped.
The same column modulation unit may include only modulation columns obtained by integral molding, modulation columns formed by lamination, and different modulation columns formed by integral molding and lamination.
On the basis of the above embodiment, the fingerprint living body identification apparatus provided in the embodiment of the present invention further includes: a lens group;
The light source module is arranged between the display screen and the spectrum imaging chip, and the lens group is arranged between the light source module and the spectrum imaging chip; or alternatively
The light source module is arranged below a non-fingerprint detection area of the display screen, and the lens group and the spectrum imaging chip are sequentially arranged below the fingerprint detection area;
The lens group is used for collimating and incidence the target light beam on the spectrum imaging chip so as to enable the target light beam to be imaged on the spectrum imaging chip.
Specifically, as shown in fig. 11, the lens group 600 is disposed between the display screen 300 and the spectral imaging chip 100, and the lens group 600 is disposed between the light source module 200 and the spectral imaging chip 100.
As shown in fig. 12, the light source module 200 is disposed below the non-fingerprint detection area of the display screen 300, and the lens group 600 and the spectral imaging chip 100 are sequentially disposed below the fingerprint detection area of the display screen 300.
Filters may be integrated into the lens assembly to filter out light in a particular wavelength range of interest, such as 400nm to 598nm, and to remove other interfering light. The vertical thickness of the lens module may be 0.5mm-20mm. Preferably, the vertical thickness of the lens module may be 5mm to 10mm.
The lens group can smoothly guide the target light beam to be incident on the spectrum imaging chip so as to ensure that the target light beam is imaged on the spectrum imaging chip.
On the basis of the above-described embodiments, the modulation unit includes, but is not limited to, a one-dimensional photonic crystal, a two-dimensional photonic crystal, a surface plasmon, a metamaterial, a super surface, and the like. Specific materials may include silicon, germanium, silicon germanium materials, silicon compounds, germanium compounds, metals, group III-V materials, and the like, wherein silicon compounds include, but are not limited to, silicon nitride, silicon dioxide, silicon carbide, and the like.
On the basis of the embodiment, in the longitudinal direction, the light modulation layer may include at least one layer of sub-modulation layer disposed along the thickness direction, and the materials of each layer of sub-modulation layer may be the same or different, so as to increase the modulating capability of the light modulation layer on the spectrum of the target beam, so that the sampling capability of the light modulation layer on the target beam is stronger, and the spectrum recovery precision is beneficial to being improved. The light modulation layer may have the following four cases in the longitudinal direction.
1) As shown in fig. 13, the polarization-independent light modulation layer is a single material layer, including the first sub-modulation layer 117, and the thickness of the light modulation layer is 60nm to 1200nm.
2) As shown in fig. 14 and 15, the polarization-independent light modulation layer 110 may include a plurality of sub-modulation layers, each of which is different in material. The thickness of each sub-modulation layer is 60 nm-1200 nm. The material of each sub-modulation layer may include silicon, germanium, silicon germanium materials, silicon compounds including, but not limited to, silicon nitride, silicon dioxide, silicon carbide, etc., germanium compounds, metals, group III-V materials, etc. Such as the embodiment shown in fig. 14, the light modulation layer includes a first sub-modulation layer 117 and a second sub-modulation layer 118; such as the embodiment shown in fig. 15, the light modulation layer includes a first sub-modulation layer 117, a second sub-modulation layer 118, and a third sub-modulation layer 119.
3) As shown in fig. 16, the polarization-independent light modulation layer 110 may include a plurality of sub-modulation layers, each of which is different in material. The thickness of each sub-modulation layer is 60 nm-1200 nm. One or more of the sub-modulation layers may not be penetrated by modulation aperture 116. The material of each sub-modulation layer may include silicon, germanium, silicon germanium materials, silicon compounds including, but not limited to, silicon nitride, silicon dioxide, silicon carbide, etc., germanium compounds, metals, group III-V materials, etc.
4) As shown in fig. 17, the polarization independent light modulation layer 110 is prepared by directly etching a structure on the light detection layer 122 of the backside illuminated CIS wafer, and the etching depth is 60nm to 1200nm.
On the basis of the above embodiment, in the longitudinal structure, the light modulation layer may not be penetrated by the modulation column or the modulation hole, the modulation column may have a certain thickness, specifically may be 60nm to 1200nm, and the thickness of the entire light modulation layer may be 120nm to 2000nm. The thickness of the modulation hole can be 160 nm-1000 nm, and the thickness of the whole light modulation layer is 220 nm-1500 nm.
On the basis of the embodiment, on the longitudinal structure, the light modulation layer can be formed by two layers of different materials, namely a silicon layer and a gold layer, wherein the thickness of the silicon layer can be 60-1200 nm, and the thickness of the gold layer can be 60-1200 nm.
Based on the foregoing embodiments, the image sensing layer in the embodiments of the present invention is specifically a CIS wafer, and the CIS wafer may be either a front-illuminated type or a back-illuminated type. As shown in fig. 18, the front-illuminated CIS wafer includes a light detection layer 122 and a metal line layer 121 connected in the thickness direction of an image sensing layer; the light detection layer 122 is below the metal line layer 121, the CIS wafer does not integrate the micro lenses and the optical filters, and the light modulation layer is directly integrated onto the metal line layer 121. The metal line layer 121 is used for performing preliminary signal processing on the spectrum signal received by the wafer, so as to convert the optical signal data of the target beam into an electrical signal, so that the processing efficiency of the signal processing circuit module can be increased, and the signal conversion and the signal operation processing are more stable and more accurate.
As shown in fig. 19, the backside CIS wafer includes a light detection layer 122 and a metal line layer 121 connected in the thickness direction of the image sensing layer; the light detection layer 122 is over the metal line layer 121, the CIS wafer does not integrate microlenses and filters, and the light modulation layer is directly integrated onto the light detection layer 122. Because the target light beam passes through the light modulation layer and then directly irradiates the light detection layer 122, adverse effects of the metal wire layer on the target light beam can be effectively eliminated, and the quantum efficiency of the spectrum imaging chip is improved.
On the basis of the above embodiment, as shown in fig. 20a and 20b, the spectral imaging chip further includes: the light-transmitting medium layer 160, the light-transmitting medium layer 160 is located between the light modulation layer 110 and the image sensing layer 120. The modulation unit of the light modulation layer 110 in fig. 20a includes a modulation hole 116, and the modulation unit of the light modulation layer 110 in fig. 20b includes a modulation column 1103. The thickness of the transparent dielectric layer 160 is 50 nm-1 μm, and the material can be silicon dioxide. In the case of a direct deposition process, the light-transmitting medium layer 160 can be covered on the image sensing layer 120 by chemical vapor deposition, sputtering, spin coating, etc., and then the light modulation layer can be deposited and etched thereon. In the case of a transfer process scheme, the light modulation layer may be first processed on the silicon dioxide, and then the two portions may be integrally transferred to the image sensing layer 120.
In some embodiments, as shown in fig. 21-26, the spectral imaging chip 100 further includes: at least one of the lens 140 and the filter 150, at least one of the lens 140 and the filter 150 is connected to a side of the light modulation layer 110 facing away from or near the image sensing layer 120.
As shown in fig. 21, the spectral imaging chip 100 is integrated with a lens 140, and the lens 140 is located on a side of the light modulation layer 110 close to the image sensing layer 120, i.e., the lens 140 is located between the light modulation layer 110 and the image sensing layer 120.
As shown in fig. 22, the spectral imaging chip 100 incorporates a lens 140, and the lens 140 is located on the side of the light modulation layer 110 facing away from the image sensing layer 120.
As shown in fig. 23, the spectral imaging chip 100 is integrated with the optical filter 150, and the optical filter 150 is located on the side of the light modulation layer 110 close to the image sensing layer 120, that is, the optical filter 150 is located between the light modulation layer 110 and the image sensing layer 120.
As shown in fig. 24, the spectral imaging chip 100 is integrated with a filter 150, and the filter 150 is located on a side of the light modulation layer 110 facing away from the image sensing layer 120.
As shown in fig. 25, the spectral imaging chip 100 integrates a lens 140 and a filter 150, and the lens 140 and the filter 150 are positioned on a side of the light modulation layer 110 facing away from the image sensing layer 120, and the filter 150 is positioned between the lens 140 and the light modulation layer 110.
As shown in fig. 26, the spectral imaging chip 100 integrates a lens 140 and a filter 150, and the lens 140 and the filter 150 are positioned on a side of the light modulation layer 110 near the image sensing layer 120, i.e., the lens 140 and the filter 150 are positioned between the light modulation layer 110 and the image sensing layer 120, and the filter 150 is positioned between the lens 140 and the image sensing layer 120.
In summary, the spectral imaging chip adopted in the embodiment of the invention has the following effects: 1) The spectrum imaging chip can collect image information and spectrum information at the same time, and provides the spectrum information of different points in the visual field while providing complete image information. 2) The preparation of the spectrum chip can be completed through one-time flow of the CMOS process, which is beneficial to reducing the failure rate of the device, improving the yield of the device and reducing the cost. 3) The light modulation layer and the image sensing layer are monolithically integrated, and no discrete component exists, so that the stability of the device is improved, and the miniaturization and the light weight of the image sensor are greatly promoted. 4) The monolithic integration is realized at the wafer level, the distance between the sensor and the light modulation layer can be reduced to the greatest extent, the size of the unit is reduced, higher resolution is realized, and the packaging cost is reduced.
Further, as shown in fig. 27, the present invention provides an optical fingerprint recognition assembly, which includes a display screen 300 and a fingerprint module 1000, wherein the fingerprint module 1000 is disposed at a lower end of the display screen 300, wherein the display screen 300 may be implemented as an LCD screen, an OLED screen, or the like; further, the optical fingerprint recognition assembly further includes a light source module 200, the light source module 200 is disposed on the fingerprint living body recognition device, and the light source module 200 is disposed corresponding to the fingerprint module 1000. In recognition, the light source module 200 emits light to the object 500 to be detected, and the object 500 to be detected reflects the light to obtain a target beam, and the target beam is incident to the fingerprint module 1000 and received.
In a separate embodiment, the fingerprint module is not necessarily used in combination with the display screen, i.e. in this embodiment application, the display screen is not required to be provided by the end product, and the fingerprint module can also realize fingerprint recognition.
It should be noted that, in a specific embodiment, the light source module 200 is integrated in the display screen 300, for example, when the display screen 300 is implemented as an OLED screen, the light beam projected by the display screen itself may be used to assist in identifying the object 500 to be detected.
Further, as shown in fig. 28, the fingerprint module 1000 includes a spectral imaging chip 100 and a circuit board 1001, wherein the spectral imaging chip 100 is electrically connected to the circuit board 1001, and preferably, the spectral imaging chip 100 is attached to the circuit board 1001. The circuit board 1001 may be implemented as a hard board (Printed Circuit Board, PCB), a flexible board (Flexible Printed Circuit, FPC), a flexible-rigid board (F-PCB), a ceramic substrate, etc., which is mainly used to conduct and/or support the spectral imaging chip 100.
Further, for example, the spectral imaging chip 100 is attached to the circuit board 1001, and the spectral imaging chip 100 may be conducted with the circuit board 1001 through a wire bonding, or may be directly conducted with a pad point; in various embodiments, the fingerprint module further includes a stiffener 1002, the stiffener 1002 being attached to the circuit board 1001 to enhance the reliability strength of the fingerprint module 1000. In a specific embodiment, the fingerprint module 1000 further includes a package 1003 formed on the upper surface of the circuit board 1001, and the package 1003 may be integrally formed on the circuit board by a molding process or may be applied to the circuit board 1001 as a gel. It should be noted that, the packaging part 1003 may also integrally wrap the lead for conducting, the packaging part 1003 is favorable to improving the reliability of the fingerprint module, and the packaging part 1003 further has a flat surface, so that the fingerprint module is better attached to the display screen 300. Because of the presence of the stiffener 1002, the circuit board may be implemented as a flexible board, thereby reducing the thickness of the fingerprint module. In some embodiments, the fingerprint module 1000 may further include a light shielding portion 1004, where the light shielding portion 1004 is disposed on the upper surface of the packaging portion 1003, so as to prevent stray light from entering and affecting imaging. The light shielding portion may be implemented as foam.
In another embodiment of the present invention, as shown in fig. 29, the fingerprint module 1000 includes a spectral imaging chip 100, a circuit board 1001, a bracket 1005 and a light source module 200, wherein the spectral imaging chip 100 and the bracket 1005 are fixed on the circuit board 1001, and the light source module 200 is fixed on the bracket 1005.
Further, the fingerprint module according to the embodiment of the present invention may further include a lens group for optical focusing, where the lens group is disposed on the photosensitive path of the spectral imaging chip 100. The lens assembly may be a vertical collimator, a thin film lens, a microlens array, a wide angle lens, or the like.
The apparatus embodiments described above are merely illustrative, wherein the elements illustrated as separate elements may or may not be physically separate, and the elements shown as elements may or may not be physical elements, may be located in one place, or may be distributed over a plurality of network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art will understand and implement the present invention without undue burden.
From the above description of the embodiments, it will be apparent to those skilled in the art that the embodiments may be implemented by means of software plus necessary general hardware platforms, or of course may be implemented by means of hardware. Based on this understanding, the foregoing technical solution may be embodied essentially or in a part contributing to the prior art in the form of a software product, which may be stored in a computer readable storage medium, such as ROM/RAM, a magnetic disk, an optical disk, etc., including several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the method described in the respective embodiments or some parts of the embodiments.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.