TW202305658A - Biometric identification device and identification method thereof - Google Patents

Abstract

A biometric identification device includes a substrate, a plurality of photosensitive devices, a first electrode group, a first dielectric layer, a first light-shielding part, a second dielectric layer, a second light-shielding part, a second electrode group and a liquid crystal layer. The photosensitive devices are disposed on the substrate. The first dielectric group is connected to the photosensitive devices. The first light-shielding part is disposed on the first dielectric layer. The second dielectric layer is disposed on the first light-shielding part. The second light-shielding part is disposed on the second dielectric layer. The second electrode group includes a pixel electrode group disposed on the second light-shielding part. The liquid crystal layer is disposed on the pixel electrode group and the second light-shielding part.

Description

Biometric identification device and identification method thereof

The present disclosure relates to a biometric identification device and an identification method thereof.

With the development of technology, information security has become an important consideration for consumers when using electronic devices. Therefore, most of the electronic devices are currently equipped with an identity authentication mechanism, and the method of identifying the identity using biometric features is a trend in recent years.

However, due to the extremely thin or almost non-existent fat layer on the surface to be tested (such as dry fingers), some testees cause air bubbles (air) to exist in the position where the fat layer is theoretically, and the lifting of the air-glass reflected light occurs theoretically Due to the probability of the darker area (dark area), the gray scale of the dark area is reversed into a brighter area (bright area), resulting in abnormal identification of biometric features.

Therefore, how to provide a biometric identification device that improves gray scale inversion and enhances biometric identification is a problem to be solved.

Some embodiments of the present disclosure provide a biometric identification device, including a substrate, a plurality of photosensitive elements, a first electrode group, a first dielectric layer, a first light-shielding part, a second dielectric layer, a second light-shielding part, a first Two electrode groups, a second electrode group and a liquid crystal molecule layer. A plurality of photosensitive elements are arranged on the substrate. The first electrode group is connected to the photosensitive element. The first dielectric layer is disposed on the photosensitive element. The first light-shielding portion is disposed on the first dielectric layer, wherein the first light-shielding portion has a plurality of first light-transmitting regions and a first light-shielding region between two adjacent first light-transmitting regions. The second dielectric layer is disposed on the first light shielding portion. The second light-shielding portion is disposed on the second dielectric layer, wherein the second light-shielding portion has a plurality of second light-transmitting regions and a second light-shielding region between two adjacent second light-transmitting regions, each second light-transmitting region The regions correspond to the first light-transmitting regions. The second electrode group includes a pixel electrode group disposed on the second light shielding portion. The liquid crystal molecule layer is disposed on the pixel electrode group and the second light shielding portion.

In some embodiments, the second electrode group further includes a driving electrode group, the driving electrode group is located on the second dielectric layer, and the pixel electrode group includes a plurality of pixel electrodes, and each pixel electrode is respectively located in each second light-transmitting region .

In some embodiments, the driving electrode group includes a plurality of driving electrodes, and each driving electrode and each pixel electrode are arranged in parallel and spaced in the second light-transmitting region.

In some implementations, each driving electrode and each pixel electrode are arranged in the second light-transmitting region at interdigitated intervals.

In some embodiments, the driving electrode group is disposed on the liquid crystal molecule layer.

In some embodiments, the biometric identification device further includes a plurality of microlenses disposed on the liquid crystal molecule layer, wherein each microlens corresponds to each second light transmission region.

In some embodiments, the biometric identification device further includes a filter layer disposed on the liquid crystal molecule layer, wherein the filter layer includes a plurality of filter units, and each filter unit corresponds to each second light transmission region.

In some embodiments, each filter unit passes monochromatic light respectively.

In some embodiments, the biometric identification device further includes a light-shielding layer disposed between the filter units.

In some embodiments, the biometric identification device further includes a control chip connected to the photosensitive element and the second electrode group, wherein the control chip is configured to determine whether to activate the second electrode group according to the state of light detected by each photosensitive element, and At least one of the pixel electrodes is selected to be activated.

Some embodiments of the present disclosure provide a method for identifying biometric features, including: performing a biometric identification step, detecting reflected light received by a plurality of photosensitive elements reflected from a living body to obtain a biometric pattern, and the biometric pattern is formed by the photosensitive A combination of multiple pattern units obtained by the component; judge whether the difference between the gray levels of adjacent pattern units is greater than or equal to 51, where the gray level is black when the gray level is 0, and the gray level is 255 When the difference is greater than or equal to 51, it is confirmed that the biometric pattern recognition is successful; when the difference is less than 51, and the average gray level of the biometric pattern is greater than 178 or less than 76, then adjust the exposure time and perform the biological feature recognition step again; or when the difference is less than 51, and the average gray scale of the biological feature pattern is 76 to 178, then turn on the electrode group to deflect the liquid crystal molecular layer on the photosensitive element, and reduce the liquid crystal molecular layer light transmittance; and performing the biometric identification step again.

In some embodiments, the step of turning on the electrode group to deflect the liquid crystal molecular layer on the photosensitive element includes: turning on a plurality of pixel electrodes and a plurality of driving electrodes corresponding to the pattern units whose difference is less than 51, so that the corresponding liquid crystal molecular layer in the liquid crystal molecular layer deflection in part of the pattern unit.

The following will clearly illustrate the spirit of the disclosure with drawings and detailed descriptions. Anyone with ordinary knowledge in the technical field can learn the technology taught by the disclosure after understanding the preferred implementation modes and examples of the disclosure. Changes and modifications are made without departing from the spirit and scope of the disclosure.

As used herein, "about," "approximately," or "substantially" includes stated values and averages within acceptable deviations from a particular value as determined by one of ordinary skill in the art, taking into account the measurements in question and relative A specific amount of measurement-related error (ie, a limitation of the measurement system). For example, "about" can mean within one or more standard deviations, or within ±30%, ±20%, ±10%, ±5% of the stated value. Furthermore, the terms "about", "approximately", "similar" or "substantially" used herein may select a more acceptable range of deviation or standard deviation based on optical properties, etching properties or other properties, instead of using a standard Deviations apply to all properties.

Exemplary embodiments are described herein with reference to top schematic illustrations that are idealized embodiments. Accordingly, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances are to be expected. Thus, embodiments described herein should not be construed as limited to the particular shapes of regions as illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, a region shown or described as flat, may, typically, have rough and/or non-linear features. Additionally, acute corners shown may be rounded. Thus, the regions shown in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region and are not intended to limit the scope of the claims.

Several implementations are listed below to describe the touch device of the present invention in more detail, but they are only for illustrative purposes and are not intended to limit the present invention. The scope of protection of the present invention shall prevail as defined by the scope of the appended patent application .

FIG. 1A shows a schematic cross-sectional view of a biometric identification device 100 according to some embodiments of the present disclosure.

In some implementations, the biological feature identification device 100 can be applied to fingerprint identification, and the identified biological features are, for example, the features in the ridges and valleys of the fingerprint, but are not limited thereto. In some other implementations, the biometric identification device 100 can also be applied to palmprint identification, and the identified biometric features can be features in the ridge-valley pattern of the identified palmprint. For ease of description, fingerprint recognition is used as an example below.

The biometric identification device 100 includes a substrate 110, a buffer layer 120, a gate dielectric layer GI, an interlayer dielectric layer ILD, a first electrode group E1, a plurality of photosensitive elements PS, an insulating layer 130, a dielectric layer 140, a first light-shielding part 150 , the second light shielding part 160 , the liquid crystal molecule layer 170 , the microlens LN, and the cover plate 180 .

Please refer to FIG. 1A , the buffer layer 120 is disposed on the substrate 110 . The gate dielectric layer GI is disposed on the buffer layer 120 . The interlayer dielectric layer ILD is disposed on the gate dielectric layer GI. The first electrode group E1 is disposed on the interlayer dielectric layer ILD. The photosensitive element PS is disposed on the first electrode group E1 and electrically connected to the first electrode group E1 . The insulating layer 132 is disposed on the first electrode group E1 and the interlayer dielectric layer ILD. The insulating layer 134 is disposed on the insulating layer 132 and the photosensitive element PS, and fills the groove A. As shown in FIG. In some embodiments, the insulating layer 132 partially covers the photosensitive unit SRO in the photosensitive element PS, for example, covers the outer edge area of the photosensitive unit SRO. Specifically, after the photosensitive unit SRO is disposed on the first electrode group E1, the insulating layer 132 is disposed on the photosensitive unit SRO, and then, a groove A is formed in the insulating layer 132 on the central part of the photosensitive unit SRO, exposing the A part of the photosensitive unit SRO; then, forming a transparent electrode TE on the insulating layer 132 and extending into the groove A, covering part of the photosensitive unit SRO (for example, covering the central area of the photosensitive element SR).

In some embodiments, the substrate 110 can be a light-transmitting material. For example, the substrate 110 can be a glass substrate, a quartz substrate, a sapphire substrate, an organic polymer substrate or other suitable hard substrates or flexible substrates (flexible substrates). wait.

In some embodiments, the material of the insulating layer 132 can be a transparent insulating material, such as silicone rubber, acrylic resin, unsaturated polyester, polyurethane, epoxy resin, other suitable materials, or derivatives thereof. The material of the insulating layer 134 may be the same as or similar to that of the insulating layer 132 .

In some embodiments, the material of the first electrode group E1 is a metal material, such as an opaque metal material. It should be noted that the first electrode group E1 in FIG. 1A is only an example, and the specific electrode connection method can refer to the following FIG. 1B and FIG. 1C or FIG. 1D .

In some embodiments, the photosensitive element PS includes a photosensitive unit SRO and a transparent electrode TE disposed on the photosensitive unit SRO. The material of the photosensitive unit SRO includes Silicon-Rich Oxide (SRO). When the photosensitive unit SRO is irradiated by light, electron-hole pairs are generated due to the characteristics of the material excited by the incident light, and can be applied under the condition of an external bias ( or an external electric field, such as the electric field applied by the first electrode group E1), to separate these electron-hole pairs generated by light excitation to form a photocurrent signal, and then convert the photocurrent signal into different gray scales (such as 256-level grayscale from grayscale 0 (black) to grayscale 255 (white)) presents a grayscale spectrum signal. Then, through the gray scale distribution in the gray scale spectrum signal, the peaks and valleys in the fingerprint are identified. In some embodiments, according to the luminance value from dark to bright, the gray level of the gray scale map signal can be divided into 256 levels, the gray level of 0 is black, and the gray level of 255 is white.

Generally speaking, in the grayscale spectrum signal, when the gray level is low (dark, such as gray level 0 to gray level 76 (about 0% to 30% of the maximum gray level)), it is judged as a peak, and when the gray level is high (bright , such as grayscale 178 to grayscale 255 (about 70% to 100% of the maximum grayscale)), it is judged as a valley. The reason is that there is usually a fat layer on the surface of the crest, and the proportion of air is relatively low. Therefore, the light reflected by the crest (mainly grease-peak reflection) is less than the light reflected by the trough (including air-grain). Valley reflected light and air-cover reflected light), the reflected light intensity of the peak is weaker, so the gray scale is lower.

In some embodiments, the material of the transparent electrode TE includes a transparent conductive material, such as indium tin oxide (Indium Tin Oxide; ITO), indium zinc oxide, aluminum tin oxide, aluminum zinc oxide, indium gallium zinc oxide, Other suitable oxides are stacked layers of at least two of the above.

Please continue to refer to FIG. 1A , the dielectric layer 142 is disposed on the insulating layer 134 . The first light-shielding portion 150 is disposed on the dielectric layer 142, wherein the first light-shielding portion 150 has a plurality of first light-transmitting regions LT1 and a first light-shielding region BR1 located between two adjacent first light-transmitting regions LT1, respectively. The first light transmission area LT1 corresponds to and overlaps with the individual photosensitive unit SRO (for example, the center point of the individual first light transmission area LT1 overlaps with the center point of the photosensitive unit SRO).

In some embodiments, the material of the dielectric layer 142 can be an organic material, an inorganic material or a combination thereof, including, but not limited to, epoxy resin, silicon oxide (SiOx), silicon nitride (SiNx), silicon oxide and nitrogen A composite layer composed of silicon and silicon, or other suitable dielectric materials. In some embodiments, the dielectric layer 142 is a transparent insulating material.

In some embodiments, the material of the first light-shielding region BR1 can be inorganic material, organic material, metal, other suitable materials, or a combination thereof. In some embodiments, the first light-shielding region BR1 includes a light-shielding metal layer and a metal oxide layer disposed on the light-shielding metal layer (not shown).

The insulating layer 136 is disposed on the dielectric layer 142 and the first light-shielding region BR1 , and fills up the first light-transmitting region LT1 . The material of the insulating layer 136 can be the same as or similar to that of the insulating layer 132 , which will not be repeated here.

The dielectric layer 144 is disposed on the insulating layer 136 . The second light-shielding portion 160 is disposed on the dielectric layer 144, wherein the second light-shielding portion 160 has a plurality of second light-transmitting regions LT2 and a second light-shielding region BR2 between two adjacent second light-transmitting regions LT2, respectively. The second light transmission area LT2 corresponds to the individual first light transmission area LT1 (for example, the center point of the individual second light transmission area LT2 overlaps with the center point of the individual first light transmission area LT1 ). The second electrode group E2 is disposed on the dielectric layer 144 , the second light-shielding region BR2 covers part of the second electrode group E2 , and the second light-transmitting region LT2 vertically corresponds to part of the second electrode group E2 . It can be understood that the second electrode group E2 in FIG. 1A is only an example, and the specific electrode connection method can refer to the following FIG. 1B and FIG. 1C or FIG. 1D.

In some embodiments, the material of the second light-shielding region BR2 can be inorganic material, organic material, metal, other suitable materials, or a combination thereof. In some embodiments, the second light-shielding region BR2 includes a light-shielding metal layer BM and a metal oxide layer OX is disposed on the light-shielding metal layer BM.

The insulating layer 138 is disposed on the second light-shielding region BR2 and fills up the second light-transmitting region LT2 . The material of the insulating layer 138 can be the same as or similar to that of the insulating layer 132 , which will not be further described here.

The liquid crystal molecular layer 170 is disposed on the second electrode group E2 and the second light-shielding portion 160. The liquid crystal molecular layer 170 responds to the electric field by deflecting or otherwise orienting itself through the orientation and intensity of the electric field provided by the second electrode group E2, thereby changing The light transmittance of the liquid crystal molecule layer 170 (transmissivity). In some embodiments, the light transmittance of the liquid crystal molecular layer 170 is 90% to 100%. When the second electrode group E2 generates an electric field, the liquid crystal molecular layer 170 is prompted to deflect, thereby reducing the light transmittance, for example, reducing the light transmittance. Penetration rate to 10% to 30%. In one embodiment, the second electrode group E2 can selectively apply an electric field to the liquid crystal molecules in the specific second light-transmitting region LT2, that is, the liquid crystal molecules in the liquid crystal molecule layer 170 can not only deflect the whole layer, but It can be deflected in a specific area, so as to adjust the incident light from the specific second light-transmitting area LT2, for example, it can deflect the liquid crystal molecules in the first part 171, reduce the light transmittance of the first part 171, but do not change The light transmittance of liquid crystal molecules in the second part 172 and the third part 173 .

It can be understood that, in some embodiments, the fat layer on the surface of part of the testee's finger is extremely thin or almost non-existent (hereinafter referred to as dry finger), which increases the probability of air bubbles (air) existing between the cover plate 180 and the finger, As a result, when fingerprints are detected, in addition to the grease-rib reflected light, there is also air-glass reflected light between the crest and the cover plate 180, and the air-glass reflected light will increase the sensitivity detected by the photosensitive unit SRO at the crest. The brightness of the light (compared with the theoretically measured light brightness of the peak) causes the position that should be recognized as the peak (generally speaking, the gray level is low), but the gray level is reversed, showing a high gray level (bright, such as gray Intensity 178 to grayscale 255) images, but can not distinguish the peaks and valleys, resulting in abnormal identification of fingerprint images.

However, through the setting of the second electrode group E2 and the liquid crystal molecule layer 170, the light transmittance of the liquid crystal molecules in a specific area can be regulated. When the difference is less than 51), the light transmittance of the liquid crystal molecules in the abnormal area can be reduced, and the recognition of the fingerprint image can be improved.

A plurality of microlenses LN are disposed on the second light-shielding portion 160, wherein individual microlenses LN correspond to individual second light transmission areas LT2 (for example, the center points of individual second light transmission areas LT2 are located on the perpendicular bisectors of individual microlenses LN) .

In some embodiments, by adjusting the radius of curvature of the microlens LN and the position of the convex portion LNa of the microlens LN, the imaging of reflected light can be adjusted (for example, the external light signal is amplified via the microlens LN), so as to obtain a fingerprint image.

The adhesive layer OC is disposed on the microlens LN. In some embodiments, the adhesive layer OC is transparent optical glue.

The cover plate 180 is disposed on the adhesive layer OC.

In some embodiments, the cover plate 180 includes at least one of a protection plate, a touch panel, and a display panel, so as to provide a function of protecting the microlens LN, or a function of touch control, or even a function of displaying an image.

Next, please refer to FIG. 1B. FIG. 1B shows a schematic cross-sectional view of a biometric identification device 100 according to some embodiments of the present disclosure, mainly showing the first electrode group E1 in the super fringe field switching mode (Advanced Fringe Field Switching; AFFS) set the second electrode group E2, and control the position and connection mode of the wafer WF.

The first electrode group E1 includes an active element T1 and a first circuit ET1 . The active device T1 includes a semiconductor layer SC1 and a gate electrode GE1 on the semiconductor layer SC1 . The semiconductor layer SC1 includes a source/drain region S/D1 and the channel region CA1 is connected to the source/drain region S/D1. In some embodiments, the channel region CA1 is polysilicon (Poly-Silicon), and the source/drain region S/D1 is doped polysilicon. In some other embodiments, the source/drain region S/D1 may be an alloy, a nitride of a metal material, an oxide of a metal material, an oxynitride of a metal material, or other suitable materials.

In one embodiment, the semiconductor layer SC1 is formed on the buffer layer 120 by patterning, and then the gate dielectric layer GI covers the semiconductor layer SC1. The gate electrode GE1 is patterned and formed on the gate dielectric layer GI. The source/drain region S/D1 is formed after the semiconductor layer SC1 is doped, and the undoped region of the semiconductor layer SC1 (located below the gate electrode GE1 ) is the channel region CA1. The interlayer dielectric layer ILD is formed on the gate dielectric layer GI and covers the gate electrode GE1. Next, openings are formed in the gate dielectric layer GI and the interlayer dielectric layer ILD (through the gate dielectric layer GI and the interlayer dielectric layer ILD), and metal materials are deposited and patterned in the openings to form the first line ET1 in the opening and on the interlayer dielectric layer ILD. Next, the photosensitive unit SRO is disposed on the first line ET1, so as to electrically connect the source/drain region S/D1 and the photosensitive unit SRO through the first line ET1.

The second electrode group E2 includes a pixel electrode group Px, a driving electrode group Com, and an active element T2. The driving electrode group Com is located on the dielectric layer 144 and includes a plurality of driving electrodes Com1. The pixel electrode group Px is located on the insulating layer 138 and includes a plurality of pixel electrodes Px1. The pixel electrode group Px passes through the insulating layer 138, the dielectric layer 144, the insulating layer 136, the dielectric layer 142, the insulating layer 134, the insulating layer 132, the interlayer The dielectric layer ILD and the gate dielectric layer GI are electrically connected to the active device T2. The configuration of the active element T2 may be the same as or similar to that of the active element T1 , which will not be repeated here. In some embodiments, the second electrode group E2 further includes a second line ET2 connected to the active element T2 and the pixel electrode group Px.

Please refer to FIG. 1C , which shows a top view of the dielectric layer 144 , the pixel electrode Px1 and the driving electrode Com1 in the box Box of FIG. 1B . The pixel electrode Px1 and the driving electrode Com1 are disposed on the dielectric layer 144 and arranged parallel to each other in the second light-transmitting region LT2 (see also FIG. 1B ). For example, as shown in FIG. 1C , the pixel electrodes Px1 and the driving electrodes Com1 are arranged in the second light-transmitting region LT2 at interdigitated intervals (please also refer to FIG. 1B ). In addition, the dielectric layer 144 is also provided with a plurality of holes G to allow light to enter the photosensitive unit SRO (refer to FIG. 1B ).

Please return to FIG. 1B. It can be understood that, through the arrangement of the pixel electrode group Px and the driving electrode group Com in the second electrode group E2, and with a suitable arrangement of liquid crystal molecules, the electric field generated by the second electrode group E2 can be The light transmittance of the liquid crystal molecule layer 170 above the second light-transmitting region LT2 (see FIG. 1B ) is changed.

Please refer back to FIG. 1B, the control chip WF is connected to the photosensitive element PS and the second electrode group E2, wherein the control chip WF is configured to determine whether to activate the second light sensor according to the state of light detected by the photosensitive element PS in the second light transmission area LT2 Two electrode groups E2, and a specific pixel electrode Px1 to be activated is selected from all the pixel electrodes Px1. That is, the control chip WF selectively activates a specific electric field according to the detection result of the photosensitive element PS, so as to change the light transmittance of the liquid crystal molecules on the specific second light transmission area LT2.

In some embodiments, when the fingerprint identification is abnormal (for example, the subject has dry fingers, and the difference in the gray scale of the pattern units detected by multiple adjacent photosensitive units SRO is less than 50), the liquid crystal The light transmittance of the molecules reduces the intensity of light received by the photosensitive elements PS that detect abnormalities, improves the gray scale inversion phenomenon during dry finger detection, and improves the recognition of fingerprints.

It should be noted that the second electrode group E2 can adopt other arrangements. For example, please refer to FIG. 1D, which shows a schematic cross-sectional view of a biometric identification device 100 according to another embodiment of the present disclosure. The first electrode group E1 and the control chip WF in FIG. 1D can be the same as those in FIG. 1B or similar, and will not be repeated here.

The difference between the second electrode group E2 in FIG. 1D and FIG. 1B is that the driving electrode group Com in FIG. 1D is disposed on the liquid crystal molecule layer 170 and not located in the second light-transmitting region LT2 . The pixel electrode group Px is located in the second light-transmitting region LT2 and directly disposed on the metal oxide layer OX of the second light-shielding region BR2 . The driving electrode group Com and the pixel electrode group Px are arranged in parallel on the upper and lower layers, and the liquid crystal molecular layer 170 is sandwiched between them. When the driving electrode group Com and the pixel electrode group Px generate an electric field, the liquid crystal molecular layer 170 in a specific area can be deflected, and the liquid crystal molecular layer 170 can be reduced. Light transmittance of layer 170.

Although the arrangement of the second electrode group E2 in FIG. 1D is different from the second electrode group E2 in FIG. 1B , with a suitable arrangement of liquid crystal molecules, the second electrode group E2 in FIG. 1B and FIG. 1D can be based on Control the instructions of the wafer WF, apply an electric field to a specific area, reduce the light transmittance of the liquid crystal molecular layer 170 above the specific second light-transmitting area LT2, reduce the light intensity received by the specific photosensitive unit SRO, and improve the performance of gray scale inversion Identify bad problems.

Please refer to FIG. 2A. FIG. 2A shows a flow chart of a method 200 for identifying biometric features according to some embodiments of the present disclosure. For the convenience of description, reference may be made to FIG. 1A to FIG.

First, in step S210, the biometric identification step is performed to detect the reflected light received from the living body by multiple photosensitive elements PS to obtain a biometric pattern. The biometric pattern is obtained by a plurality of pattern units obtained by a plurality of photosensitive elements PS In combination, a single photosensitive element PS obtains a pattern unit. In some embodiments, the biometric pattern is a gray scale signal converted from an optical signal. In one embodiment, according to the luminance value from dark to bright, the grayscale of the grayscale signal can be divided into 256 levels, grayscale 0 is black, grayscale 255 is white, grayscale 1 to grayscale 254 is The transition color between black and white, as the gray scale increases, it becomes closer to white.

Next, see step S220, it is judged whether the difference between the gray levels of adjacent pattern units is greater than or equal to 51 (that is, the gray level difference is greater than or equal to about 20% of the maximum gray level difference).

If the difference between the gray levels of adjacent pattern units is greater than or equal to 51 (for example, the gray level of the first pattern unit is 150, the gray level of the adjacent second pattern unit is 50, and the difference is 100), Then continue to step S230, and the biometric pattern identification is successful. In some embodiments, if the fingerprint recognition is the first recording, after step S230, the biometric pattern feature point recording is performed, and the biometric pattern is recorded in the database. If this time is for general use (such as unlocking), then continue to compare whether the feature points of the biometric pattern this time are consistent with the feature points of the biometric pattern stored in the database. If the feature points are consistent, it is determined that the comparison is successful (unlocking) .

If the difference between the gray scales of adjacent pattern units is not greater than or equal to 51, that is, the gray scale difference is less than 51 (the gray scale difference is less than about 20% of the maximum gray scale difference), for example, The grayscale of one pattern unit is 10, the grayscale of the second adjacent pattern unit is 50, and the difference is 40, then first proceed to step S240 to determine whether the average grayscale of the biometric pattern is 76 to 178 (about the maximum between 30% of the grayscale and 70% of the maximum grayscale).

If the average gray scale of the biometric pattern is not 76 to 178 (that is, the average gray scale is less than 30% of the maximum gray scale, or the average gray scale is greater than 70% of the maximum gray scale), it may be underexposed or exposed. If the amount is too high, and the overall field of view is too dark or too bright, proceed to step S252 to adjust the exposure time (for example, if the average gray level is less than 76, then lengthen the exposure time, and if the average gray level is greater than 178, then shorten the exposure time). After step S252, step S254 is continued, and the biometric identification step of step S210 is executed again.

If the average grayscale of the biometric pattern is 76 to 178 (that is, the average grayscale is about 30% to 70% of the maximum grayscale), and the exposure is within an appropriate range, then it is judged that the adjacent steps of step S220 cannot be achieved. The reason why the difference between the gray scales of the pattern units is greater than or equal to 51 (the criterion for correct recognition of the biometric pattern) may be the gray scale inversion phenomenon caused by air bubbles in dry fingers.

Therefore, following step S262, the electrode group (ie, the second electrode group E2 in FIG. 1A to FIG. 1B ) is turned on to deflect the liquid crystal molecular layer 170 on the photosensitive element PS and reduce the light transmittance of the liquid crystal molecular layer 170. In some embodiments, the pixel electrode Px1 and the driving electrode Com1 corresponding to the adjacent pattern units whose difference is less than 51 (51.2, 20%) are turned on, so that the part of the liquid crystal molecular layer 170 corresponding to these pattern units generates deflection.

For example, please refer to FIG. 2B. FIG. 2B shows a schematic diagram of some steps in the method 200 for identifying biometric features according to some embodiments of the present disclosure, wherein FIG. 2B is basically the biometric feature identification device in FIG. 1A 100. In order to highlight the main axis of the discussion, this figure only records the component numbers mentioned in the description of the subsequent steps, and the other omitted component numbers can refer to Figure 1A.

When the average grayscale of the biometric pattern is 76 to 178, but the pattern units detected by the photosensitive elements PSA and PSC are respectively different from the grayscales of the pattern units detected by the adjacent photosensitive elements PS (not shown). The difference between them is less than 51, and the standard for correct recognition of the biometric pattern has not been reached, then the second electrode group E2 turns on the pixel electrodes Px1A and Px1C corresponding to the photosensitive elements PSA and PSC, so that the liquid crystal molecules on the photosensitive elements PSA and PSC The layer 170 is deflected to reduce the light transmittance of the light L in the liquid crystal molecule layer 170, for example, reduce the light transmittance to 10% to 30%, so that the light L passes through the second light transmission area LT2A and the second light transmission area LT2C The amount is reduced to improve the air-glass reflection of dry fingers due to the existence of air bubbles, resulting in the gray-scale inversion phenomenon of increased peak brightness, thereby improving the recognition of fingerprints.

Next, following step S264, the biometric identification step of step S210 is executed again.

It can be understood that the biometric identification device 100 of the present disclosure can also add, replace, or delete some components according to actual needs, for example, please refer to FIG. 3 to FIG. 5 .

Please refer to FIG. 3 , which is a schematic cross-sectional view of a biometric identification device 300 according to some embodiments of the present disclosure.

The biometric identification device 300 in FIG. 3 is basically the same or similar to that in FIG. 1A , the difference between them is that a single microlens LN of the biometric identification device 300 corresponds to a plurality of second light-transmitting regions LT2 .

Please refer to FIG. 4 , which is a schematic cross-sectional view of a biometric identification device 400 according to some embodiments of the present disclosure.

The biometric identification device 400 in FIG. 4 is basically the same or similar to that in FIG. 1A. The difference between the two is that the biometric identification device 400 further includes a filter layer CF disposed on the liquid crystal molecular layer 470 (for example, disposed on the adhesive layer OC and between the cover plate 480), wherein the filter layer CF includes a plurality of filter units (filter units CF1 to CF3), and individual filter units CF correspond to individual second light transmission areas LT2, for example, filter units CF1 correspond to the second transmission areas In the light area LT2A, the filter unit CF2 corresponds to the second light transmission area LT2B, and the filter unit CF3 corresponds to the second light transmission area LT2C. In addition, the biometric identification device 400 further includes a light-shielding layer LS disposed between the filter units CF.

In some implementations, the filter units CF1 to CF3 respectively pass one kind of monochromatic light. In one embodiment, the filter units CF1 to CF3 pass monochromatic light of the same color. In another embodiment, the filter units CF1 to CF3 pass monochromatic light of different colors, for example, the filter unit CF1 passes red light, the filter unit CF2 passes green light, and the filter unit CF3 passes blue light.

Please refer to FIG. 5 , which is a schematic cross-sectional view of a biometric identification device 500 according to some embodiments of the present disclosure.

The biometric identification device 500 in FIG. 5 is basically the same or similar to that in FIG. 1A. The difference between the two is that the biometric identification device 500 further includes a display layer DP disposed on the adhesive layer OC. The display layer DP can emit light to reach the biological body (such as the fingerprint of the subject) and reflect it for the photosensitive element PS to identify the fingerprint image. In some embodiments, the display layer DP includes a plurality of light-emitting pixels (pixels), and each light-emitting pixel includes a plurality of light-emitting sub-pixels (subpixels) that respectively emit one or more monochromatic lights. In one embodiment, the light-emitting sub-pixels include organic light-emitting diodes (organic light-emitting diodes, OLEDs), inorganic light-emitting diodes, or other types of sub-pixels capable of emitting light. In some other implementations, the display layer DP can also be disposed at other positions, such as under the substrate 510 .

Some embodiments of the present disclosure provide a biometric identification device and method. The photosensitive element is used to detect biometrics. When the grayscale difference between adjacent pattern units does not reach the standard for correct identification of biometric patterns, the second electrode group can Deflect the liquid crystal molecular layer in a specific area, reduce the light transmittance of the liquid crystal molecules on the abnormally detected photosensitive element, and improve the problem caused by the improper existence of air bubbles (for example, when the finger is dry, the air bubbles exist at the crest of the peak) The gray scale inversion phenomenon improves the recognition of biological features.

Although the present disclosure has been disclosed above with multiple implementations and examples, it is not intended to limit the present disclosure. Anyone skilled in the art can make various changes without departing from the spirit and scope of the present disclosure. Therefore, the scope of protection of this disclosure should be defined by the scope of the appended patent application.

100, 300, 400, 500: biometric identification device 110, 310, 410, 510: substrate 120, 320, 420, 520: buffer layer 130, 132, 134, 136, 138, 330, 332, 334, 336, 338, 432, 434, 436, 438, 532, 534, 536, 538: insulating layer 140, 142, 144, 342, 344, 442, 444, 542, 544: dielectric layer 150, 350, 450, 550: the first shading part 160, 360, 460, 560: the second shading part 170, 370, 470, 570: liquid crystal molecular layer 171: Part 1 172: Part Two 173: Part Three 180, 380, 480, 580: cover plate 200: method S210, S220, S230, S240, S252, S254, S262, S264: steps A: Groove BM: light-shielding metal layer Box: box BR1: the first shading area BR2: Second shading area CA1, CA2: Passage area CF: filter layer CF1, CF2, CF3: filter unit Com: drive electrode group Com1: drive electrode DP: display layer E1: the first electrode group E2: Second electrode group ET1: first line ET2: second line G: hole GE1, GE2: Gate electrodes GI: gate dielectric layer ILD: interlayer dielectric layer L: light LN: microlens LNa: convex part LT1: the first light transmission area LT2, LT2A, LT2B, LT2C: the second light transmission area OC: Adhesive layer OX: metal oxide layer PS, PSA, PSB, PSC: photosensitive element Px: pixel electrode group Px1, Px1A, Px1B, Px1C: pixel electrodes SC1, SC2: semiconductor layer S/D1, S/D2: source/drain regions SRO: photosensitive unit T1, T2: active components TE: transparent electrode WF: control chip

A more complete understanding of the present disclosure can be obtained by reading the following detailed description of the embodiments with reference to the accompanying drawings. FIG. 1A shows a schematic cross-sectional view of a biometric identification device according to some embodiments of the present disclosure. FIG. 1B shows a schematic cross-sectional view of a biometric identification device according to some embodiments of the present disclosure. FIG. 1C shows a top view of the dielectric layer, the pixel electrodes and the driving electrodes in the frame of FIG. 1B. FIG. 1D shows a schematic cross-sectional view of a biometric identification device according to another embodiment of the present disclosure. FIG. 2A shows a flowchart of a method for identifying biometric features according to some embodiments of the present disclosure. FIG. 2B is a schematic diagram of some steps in the method for identifying biometric features according to some embodiments of the present disclosure. FIG. 3 shows a schematic cross-sectional view of a biometric identification device according to some embodiments of the present disclosure. FIG. 4 shows a schematic cross-sectional view of a biometric identification device according to some embodiments of the present disclosure. FIG. 5 shows a schematic cross-sectional view of a biometric identification device according to some embodiments of the present disclosure.

100: Biometric identification device

110: Substrate

120: buffer layer

130, 132, 134, 136, 138: insulating layer

140, 142, 144: dielectric layer

150: the first shading part

160: the second shading part

170: liquid crystal molecular layer

171: Part 1

172: Part Two

173: Part Three

180: cover plate

A: Groove

BM: light-shielding metal layer

BR1: the first shading area

BR2: Second shading area

E1: the first electrode group

E2: Second electrode group

GI: gate dielectric layer

ILD: interlayer dielectric layer

LN: microlens

LNa: convex part

LT1: the first light transmission area

LT2: the second light transmission area

OC: Adhesive layer

OX: metal oxide layer

PS: photosensitive element

SRO: photosensitive unit

TE: transparent electrode

Claims (12)

A biometric identification device, comprising: a substrate; A plurality of photosensitive elements are arranged on the substrate; a first electrode group connected to the photosensitive elements; a first dielectric layer disposed on the photosensitive elements; A first light-shielding portion disposed on the first dielectric layer, wherein the first light-shielding portion has a plurality of first light-transmitting regions and a first light-shielding portion between two adjacent first light-transmitting regions district; a second dielectric layer disposed on the first light-shielding portion; A second light-shielding portion disposed on the second dielectric layer, wherein the second light-shielding portion has a plurality of second light-transmitting regions and a second light-shielding portion between two adjacent second light-transmitting regions regions, each of the second light-transmitting regions corresponds to each of the first light-transmitting regions; A second electrode group, wherein the second electrode group includes a pixel electrode group disposed on the second light shielding portion; and A liquid crystal molecule layer is arranged on the pixel electrode group and the second light shielding portion. The biometric identification device as claimed in item 1, wherein the second electrode group further includes a driving electrode group, the driving electrode group is located on the second dielectric layer, and the pixel electrode group includes a plurality of pixel electrodes, and each The pixel electrodes are respectively located in the second light-transmitting regions. The biometric identification device according to claim 2, wherein the driving electrode group includes a plurality of driving electrodes, and each of the driving electrodes and each of the pixel electrodes are arranged in parallel with each other and spaced apart in the second light-transmitting region. The biometric identification device as claimed in claim 3, wherein each of the driving electrodes and each of the pixel electrodes are arranged in the second light-transmitting region at interdigitated intervals. The biometric identification device according to claim 2, wherein the driving electrode group is disposed on the liquid crystal molecule layer. The biometric identification device as claimed in claim 1 further includes a plurality of microlenses disposed on the liquid crystal molecule layer, wherein each of the microlenses corresponds to each of the second light-transmitting regions. The biometric identification device as described in Claim 1 further includes a filter layer disposed on the liquid crystal molecule layer, wherein the filter layer includes a plurality of filter units, and each filter unit corresponds to each of the second transparent light zone. The biometric identification device as claimed in claim 7, wherein each of the filter units allows a monochromatic light to pass through. The biometric identification device as claimed in Claim 7 further includes a light-shielding layer disposed between the filter units. The biometric identification device as described in claim 2, further comprising a control chip connected to the photosensitive element and the second electrode group, wherein the control chip is configured to determine whether to activate or not according to the state of light detected by each of the photosensitive elements The second electrode group, and at least one of the pixel electrodes that needs to be activated is selected. A method for identifying biometrics, comprising: Executing a biometric identification step to detect reflected light received from a body by a plurality of photosensitive elements to obtain a biometric pattern, the biometric pattern is formed by combining a plurality of pattern units obtained by the photosensitive elements ; Determine whether a difference between a grayscale of the adjacent pattern units is greater than or equal to 51, wherein the grayscale is black when the grayscale is grayscale 0, and white when the grayscale is grayscale 255, wherein When the difference is greater than or equal to 51, it is confirmed that the biometric pattern recognition is successful; When the difference is less than 51, and an average gray scale of the biometric pattern is greater than 178 or less than 76, then adjusting an exposure time; and perform the biometric identification step again; or When the amount of difference is less than 51, and the average gray scale of the biometric pattern is 76 to 178, then Turn on an electrode group to deflect a liquid crystal molecular layer on the photosensitive elements, reducing a light transmittance of the liquid crystal molecular layer; and This biometric identification step is performed again. The method for identifying biometric features as described in Claim 11, wherein the step of turning on the electrode group to deflect the liquid crystal molecular layer on the photosensitive elements includes: A plurality of pixel electrodes and a plurality of driving electrodes corresponding to the pattern units whose difference is smaller than 51 are turned on to deflect a part of the liquid crystal molecule layer corresponding to the pattern units.

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