Patent ID: 12249612

DETAILED DESCRIPTION OF THE EMBODIMENTS

In order to make objectives, technical solutions and advantages of embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are a part of embodiments of the present disclosure, rather than all the embodiments. Further, the embodiments of the present disclosure and features of the embodiments may be combined with each other under a condition of no conflict. Based on the described embodiments of the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present disclosure.

Unless otherwise defined, technical or scientific terms used in the present disclosure shall have the ordinary meaning as understood by those of ordinary skill in the art to which this present disclosure belongs. “First”. “second” and similar words used in the present disclosure do not represent any order, quantity, or importance, but are merely used to distinguish different components. Similar words such as “comprise” or “include” mean that elements or items appearing before the words encompass elements or items recited after the words and their equivalents, but do not exclude other elements or items. Words like “connected” or “linked” are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

It should be noted that dimensions and shapes of figures in the accompanying drawings do not reflect a real scale, and are only intended to illustrate the present disclosure. The same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout.

In the related art, a TFT optical fingerprint recognition sensor module includes TFT arranged on a base substrate and a photodiode electrically connected to the TFT. A drain of the TFT is used as a bottom electrode of the photodiode, and the photodiode further includes a top electrode and a photoelectric conversion layer between the top electrode and the drain. During implementation, after the photoelectric conversion layer is formed, a planarization layer needs to be formed, a patterning process is adopt to form a via hole exposing part of the photoelectric conversion layer, and the top electrode of the photodiode is formed in the via hole. However, due to a top electrode etching process, an area of the photoelectric conversion layer not covered by the top electrode is large, that is, there is no positive electric field formed by upper and lower electrodes of the photoelectric conversion layer in a region not covered by the top electrode. When voltage is applied to the upper and lower electrodes of an optoelectronic material, due to absence of positive electric field, the optoelectronic material is not completely within a range of an electric field, and carriers in an edge region are slow in speed and are easily captured by defect states in the optoelectronic material. Especially due to process conditions, there are many defect states on a sidewall of the optoelectronic material, and these captured carriers will be released in a next frame of image, resulting in image sticking and affecting image quality.

Based on the above problem in the related art, the embodiments of the present disclosure provide a fingerprint recognition module. As shown inFIG.1, the fingerprint recognition module includes:a base substrate1;a driving circuit layer9, disposed on a side of the base substrate1, and the driving circuit layer9includes a plurality of driving transistors12arranged in an array;a first insulating layer5, disposed on a side of the driving circuit layer9facing away from the base substrate1, and the first insulating layer5includes a plurality of first via holes13running through the first insulating layer5in a thickness direction of the first insulating layer5;a plurality of photoelectric converters15, disposed on a side of the first insulating layer5facing away from the driving circuit layer9), and in contact with first electrodes14of the plurality of driving transistors12through the plurality of first via holes13in one-to-one correspondence;a second insulating layer16, disposed on a side of the first insulating layer5facing away from the base substrate1, and the second insulating layer16includes a plurality of second via holes17in one-to-one correspondence with the plurality of photoelectric converters15, wherein a distance h13 between an edge of an orthographic projection of a region of a second via hole17exposing a corresponding photoelectric converter15on the base substrate1and an edge of an orthographic projection of a surface of the corresponding photoelectric converter15facing away from the base substrate1on the base substrate1is smaller than or equal to a first preset value; anda plurality of first electrodes18, disposed on sides of the plurality of photoelectric converters15facing away from the driving circuit layer9, wherein each of the plurality of first electrodes18covers, at the corresponding second via hole17, the corresponding photoelectric converter15.

In the fingerprint recognition module provided by the embodiments of the present disclosure, an area of each of the plurality of second via holes is increased, so that the distance between the edge of the orthographic projection of a region of a second via hole exposing a corresponding photoelectric converter on the base substrate and the edge of the orthographic projection of a surface of the corresponding photoelectric converter facing away from the base substrate on the base substrate is smaller than or equal to the first preset value. Correspondingly, an area of the first electrode may be increased, an area of the first electrode covering the corresponding photoelectric converter may thereby be increased, a coverage range of an electric field on the photoelectric converters may be enlarged, and a probability of photo-generated carriers being captured by defect states of sidewalls of the photoelectric converters may be reduced, so that the problem of image image-sticking may be solved and an accuracy of fingerprint recognition may be improved.

It should be noted that the fingerprint recognition module provided by the embodiments of the present disclosure is an optical fingerprint recognition module and may identify lines including fingerprints and palm prints.

It should be noted that, in the fingerprint recognition module provided by the embodiments of the present disclosure, a photodiode is constituted by the first electrode of the driving transistor, the photoelectric converter and a first electrode layer.

In some embodiments, a ratio of an area of an orthographic projection of the first electrodes on the base substrate to an area of the orthographic projection of a surface of the corresponding photoelectric converter facing away from the base substrate on the base substrate is larger than or equal to 95% and is smaller than or equal to 100%.

In some embodiments, the first preset value is 2 μm. That is, the distance h13 between the edge of the orthographic projection of the region of the second via hole exposing the corresponding photoelectric converter on the base substrate and the edge of the orthographic projection of the surface of the corresponding photoelectric converter facing away from the base substrate on the base substrate is smaller than or equal to 2 μm.

In some embodiments, the distance h13 between the edge of the orthographic projection, on the base substrate, of the region of the second via hole exposing the corresponding photoelectric converter and the edge of the orthographic projection of the surface of the corresponding photoelectric converter facing away from the base substrate on the base substrate is larger than or equal to 0.5 μm and is smaller than or equal to 2 μm.

During implementation, the first electrodes may first be formed on the sides of the plurality of photoelectric converters facing away from the base substrate, then the second insulating layer is formed, the second via holes exposing the first electrodes are formed in the second insulating layer, and the second insulating layer may cover a part of edges of the first electrode.

In some embodiments, a distance between an edge of the orthographic projection of the first electrodes on the base substrate and the edge of the orthographic projection of the surface of the corresponding photoelectric converter facing away from the base substrate on the base substrate is larger than or equal to 0 μm and is smaller than or equal to 0.5 μm.

In some embodiments, as shown inFIG.1, the first electrode fully covers the surface of the corresponding photoelectric converter15facing away from the base substrate1. That is, distances between the edges of the first electrode and edges of the surface of the corresponding photoelectric converter facing away from the base substrate are 0 μm.

Of course, in some embodiments, the first electrode may also cover a part of the sidewalls of the corresponding photoelectric converter. That is, the orthographic projection of the surface of the corresponding photoelectric converter facing away from the base substrate on the base substrate is located within the orthographic projection of the first electrode on the base substrate. Therefore, coverage of the electric field on the sidewalls of the photoelectric converters is increased, the probability of the photo-generated carriers being captured by the defect states of the photoelectric converters may be reduced, so that the problem of image image-sticking may be further solved.

In some embodiments, as shown inFIG.1andFIG.2, an orthographic projection of a photoelectric converter15on the base substrate1is located within an orthographic projection of a corresponding first via hole13on the base substrate1.

It should be noted that, in a fingerprint recognition module provided in the related art, because of an etching process, a photoelectric conversion layer and a drain have regions that are not connected through direct contact. When voltage is applied to the upper and lower electrodes of the optoelectronic material, the positive electric field is absent in the regions of the photoelectric conversion layer and the drain that are not connected through direct contact, the optoelectronic material is not completely within the range of the electric field, and the carriers in an edge region are slow in speed and are prone to being captured by the defect states in the optoelectronic material. Especially due to process conditions, there are many defect states on the sidewall of the optoelectronic material, and these captured carriers will be released in the next frame of image, resulting in image sticking and affecting image quality.

In the fingerprint recognition module provided by the embodiments of the present disclosure, the orthographic projection of the photoelectric converter on the base substrate is located within the orthographic projection of the corresponding first via hole on the base substrate, so the surfaces of the plurality of photoelectric converters close to the base substrate are completely in contact with the plurality of first electrodes of the driving transistors. Therefore, the probability of the photo-generated carriers being captured by the defect states of the sidewalls of the photoelectric converters may be reduced, so that the problem of image image-sticking may be solved and the accuracy of fingerprint recognition may be improved.

During the implementation, for example, as shown inFIG.1, an area of the first via hole13expositing the first electrode14of the driving transistor12is larger than an area of the surface of the corresponding photoelectric converter15close to the base substrate1. Or, as shown inFIG.2, the area of the first via hole13expositing the first electrode14of the driving transistor12is equal to the area of the surface of the corresponding photoelectric converter15close to the base substrate1.

In some embodiments, as shown inFIG.3, a lateral surface of the photoelectric converter15has chamfer27on a side close to the base substrate1.

In the fingerprint recognition module provided by the embodiments of the present disclosure, edge of the side of the photoelectric converter close to the base substrate has the chamfer, so that a leakage current on the sidewalls of the photoelectric converters may be reduced and influence of increased leakage current caused by increasing the area of the first electrodes may be reduced. Therefore, the accuracy of fingerprint recognition may be improved.

In some embodiments, the chamfer is an inner chamfer curved toward a center of the photoelectric converter.

In some embodiments, a shape of an orthographic projection of the chamfer on the base substrate is an arc or a zigzag line.

During the implementation, the chamfer may be formed at the edge of the side of the photoelectric converter close to the base substrate through the etching process.

In some embodiments, as shown inFIG.1,FIG.2,FIG.3, andFIG.4, the driving circuit layer9includes:a first conducting layer28, including: control electrodes19of the plurality of driving transistors12, and a plurality of scanning signal lines30;a gate insulating layer2, disposed on a side of the first conducting layer28facing away from the base substrate1;an active layer20, disposed on a side of the gate insulating layer2facing away from the first conducting layer28; anda second conducting layer29, disposed on a side of the active layer20facing away from the gate insulating layer2, and the second conducting layer includes: the first electrodes14and second electrodes21of the plurality of driving transistors12, and a plurality of data signal lines31, wherein the data signal lines31and the scanning signal lines30intersect with each other to define a plurality of fingerprint recognition units33, and the data signal lines31are electrically connected with the second electrodes21of the driving transistors12.

It should be noted that, only one fingerprint recognition unit is illustrated inFIG.4, and description is made by taking the area of the first via hole exposing the first electrode of the driving transistor being larger than the area of the surface of the corresponding photoelectric converter close to the base substrate as an example.FIG.1andFIG.3may be, for example, a sectional diagram along AA inFIG.4. InFIG.1.FIG.2.FIG.3andFIG.4, description is made by taking the driving transistor being bottom gate structure as an example. Of course, during the implementation, the driving transistor may also be top gate structure, i.e. the active layer is disposed between the control electrode and the base substrates. InFIG.4, description is made by taking the scanning signal lines30extending in a first direction X and the data signal lines36extending in a second direction Y as an example. The first direction X is perpendicular to the second direction Y.

In some embodiments, as shown inFIG.4, the first electrode14of each of the plurality of driving transistors includes: a first part34, and a second part35connected with the first part34:the orthographic projection of the first via hole13on the base substrate1is located within an orthographic projection of the first part34on the base substrate1, and a pattern of the orthographic projection of the first via hole13on the base substrate1is similar to a pattern of the orthographic projection of the first part34on the base substrate1.

In some embodiments, a ratio of the area of the orthographic projection of the photoelectric converter on the base substrate to an area of the orthographic projection of the first via hole on the base substrate is larger than or equal to 90% and is smaller than or equal to 100%.

In some embodiments, as shown inFIG.4, minimum distances h1, h2, h3 and h4 between edges of the first via holes13and the edge of the photoelectric converter15is larger than or equal to 0 μm and is smaller than or equal to 2 μm.

In some embodiments, h1=h2=h3=h4.

In some embodiments, as shown inFIG.4, minimum distances h5 and h6 between edges of the first electrode14of the driving transistors and the scanning signal lines30are larger than or equal to 3 μm and are smaller than or equal to 5 μm, and minimum distances h7 and h8 between the edges of the first electrodes14of the driving transistors and the data signal lines31are larger than or equal to 3 μm and are smaller than or equal to 5 μm.

In some embodiments, h5=h6=h7=h8.

In some embodiments, a ratio of the area of the orthographic projection of the first via hole on the base substrate to an area of the orthographic projection of the first part on the base substrate is larger than or equal to 70% and is smaller than or equal to 90%.

In some embodiments, as shown inFIG.4, minimum distances h9, h10, h11 and h12 between the edges of the first via holes13and edges of the first parts34are larger than or equal to 3 μm and are smaller than or equal to 5 μm.

In some embodiments, as shown inFIG.4, the pattern of the orthographic projection of the first via hole13on the base substrate is similar to a pattern of the orthographic projection of photoelectric converter15on the base substrate.

In some embodiments, as shown inFIG.1,FIG.2andFIG.3, the fingerprint recognition module further includes:a third insulating layer7, disposed on a side of the second insulating layer16facing away from the first insulating layer5, and including a plurality of third via holes37;a third conducting layer8, disposed on a side of the third insulating layer7facing away from the second insulating layer16, and being in contact with the plurality of first electrodes18through the plurality of third via holes;a fourth insulating layer22, disposed on a side of the third conducting layer8facing away from the third insulating layer7;a shading metal layer24, disposed on a side of the fourth insulating layer22facing away from the third conducting layer8, and an orthographic projection of the shading metal layer24on the base substrate1covers an orthographic projection of the active layer20of the driving transistors12on the base substrate1;a fifth insulating layer23, disposed on a side of the shading metal layer24facing away from the fourth insulating layer22, and the fifth insulating layer23includes fourth via holes25running through the fifth insulating layer23in a thickness direction of the fifth insulating layer; anda shielding layer26, disposed on a side of the fifth insulating layer23facing away from the shading metal layer24, and being in contact with the shading metal layer24through the fourth via holes25.

In some embodiments, the driving transistors may be, for example, thin film transistors. Materials of the control electrodes, the first electrodes and the second electrodes of the driving transistors as well as the shading metal layer may be, for example, aluminum, molybdenum, copper or other metal materials. The photoelectric converters include semiconductor electron/intrinsic/hole doped semiconductor materials, such as p-i-n doped amorphous silicon (a-Si) and polycrystalline silicon (p-Si). A material of the active layer of the driving transistors may be, for example, amorphous silicon, polysilicon, indium gallium zinc oxide (IGZO), etc. Materials of the gate insulating layer, the first insulating layer, and the third insulating layer may be, for example, silicon nitride, silicon oxide, etc. A material of the second insulating layer includes, for example, resin. An effect of the second insulating layer is to planarize film layer differences caused by deposition and etching of the photoelectric converters, so as to ensure that the layers above it will not be broken due to climbing caused by the differences. An effect of the third insulating layer is to optimize contact morphology between the planarization layer and the layers above it. Materials of the first electrodes and the third conductive layer are transparent conductive materials, for example, indium tin oxide. The third conducting layer is configured to provide common voltage signals to the first electrodes. An effect of the third insulating layer is to isolate electrical lap joint between the shading metal layer and the third conducting layer. The shading metal layer is an opaque metal layer which prevents light from irradiating channel regions of the driving transistors so as to prevent the active layer from generating relatively large leakage current due to light irradiation. Compared with other insulating layers, the fourth insulating layer is a relatively thick silicon oxide or silicon nitride film, serving to ensure that the fingerprint recognition module has certain resistance to surface scratches. The shielding layer is a layer of transparent conductive film, and its material includes, for example, indium tin oxide, etc. When the fingerprint recognition module provided by the embodiments of the present disclosure is applied to a display product, the shielding layer may shield crosstalk caused by the plurality of signal lines of a display panel on the fingerprint recognition module.

In some embodiments, as shown inFIG.1toFIG.3, a distance h14 between an edge of an orthographic projection of the third via hole37on the base substrate1and the edge of the orthographic projection of the surface of the corresponding photoelectric converter15facing away from the base substrate1on the base substrate1is larger than or equal to 3 μm s and is smaller than or equal to 6 μm.

In some embodiments, as shown inFIG.5, the fingerprint recognition module further includes:a plurality of data reading units38electrically connected with the data signal lines31in a one-to-one correspondence mode, and each of the plurality of data reading unit includes: an operational amplifier circuit39, a storage circuit40, and a switch circuit41. A first input end of the operational amplifier circuit39is coupled to a corresponding data signal line31, a first end of the storage circuit40and a first end of the switch circuit41, an output end of the operational amplifier circuit39is coupled to a second end of the storage circuit40and a second end of the switch circuit41, and the output end of the operational amplifier circuit39is configured to output fingerprint recognition signals according to data signals input by the corresponding data signal line31.

In some embodiments, as shown inFIG.6, the operational amplifier circuit39includes: a first amplifier42:a first input end of the first amplifier42is coupled to the corresponding data signal line31, the first end of the storage circuit40and the first end of the switch circuit41, and a second input end of the first amplifier42is grounded.

In some embodiments, as shown inFIG.6, the storage circuit40includes: a first capacitor43:a first electrode of the first capacitor43is coupled to the first input end of the operational amplifier circuit39, and a second electrode of the first capacitor43is coupled to the output end of the operational amplifier circuit39.

In some embodiments, as shown inFIG.6, the switch circuit41includes: a first switch44;a first end of the first switch44is coupled to the first input end of the operational amplifier circuit39, and a second end of the first switch44is coupled to the output end of the operational amplifier circuit39.

It should be noted that, a photosensitive diode inFIG.5andFIG.6includes the photoelectric converters, the first electrodes and the first electrodes of the driving transistors, the third conducting layer electrically connected with the first electrodes is electrically connected to a voltage signal end, and the voltage signal end may provide a positive voltage signal +V or a negative voltage signal −V to the first electrodes.

A driving method of the above fingerprint recognition module provided by an embodiments of the present disclosure, as shown inFIG.7, includes:S101, in an image-sticking removal stage, controlling a driving transistor of the fingerprint recognition module to be turned on, and providing an image-sticking removal signal to a photoelectric conversion part; andS102, in an image collection stage, controlling the driving transistor of the fingerprint recognition module to be turned off, and providing a common voltage signal to the photoelectric converter.

According to the driving method of the fingerprint recognition module provided by the embodiments of the present disclosure, the image-sticking removal stage is added, and the image-sticking removal signal is provided to the plurality of photoelectric converters in the image-sticking removal stage, thus enabling large current to pass an optoelectronic material of the plurality of photoelectric converters, so that defect states in the optoelectronic material may be filled by the large current. In this way, in the subsequent image collection stage, photo-generated carriers generated by the optoelectronic material upon sensing light will not be captured by the defect states, so that a problem of image image-sticking may be solved and an accuracy of fingerprint recognition may be improved.

In some embodiments, the image-sticking removal signal is electrically opposite to the common voltage signal.

In some embodiments, the image-sticking removal signal is a positive voltage signal, and the common voltage signal is a negative voltage signal.

Subsequently, description will be made by taking the fingerprint recognition module as shown inFIG.6as an example. In the image collection stage, the photoelectric conversion part receives light irradiation and provides a negative voltage signal to a photodiode. Under a negative voltage signal mode, the driving transistor of the fingerprint recognition module is turned off, and the photodiode is disconnected from a data reading unit, the optoelectronic material in the photoelectric converter generates the photo-generated carriers to accumulate charges. In the image-sticking removal stage, a positive voltage signal is provided to the photodiode, thus enabling the large current to pass the optoelectronic material of the photoelectric converter, so that the defect states in the optoelectronic material may be filled by the large current. Therefore, the photogenerated carriers generated by the optoelectronic material upon sensing the light will not be captured by the defect states, so that image-sticking is reduced.

FIG.8is a sequence diagram combination of the positive voltage signal and the negative voltage signal. As shown inFIG.8, frame timing of the image-sticking removal stage is different from frame timing of the image collection stage. At the beginning of fingerprint recognition, the positive voltage signal is applied to each frame. When exposure begins, the frame timing is restored to the frame timing of applying the negative voltage signal and the negative voltage signal is applied. After the frame timing is restored, there will be a short delay (Ndelay) by several frames, so that a detector may adapt to new frame timing and stabilize grayscale values of an image. After the Ndelay, the photodiode collects a light source signal for exposure, accumulates the photo-generated carriers and generates the image until it ends, at which point it reverts to a mode of applying the positive voltage signal.

A display apparatus provided by an embodiments of the present disclosure include the fingerprint recognition module provided by the embodiments of the present disclosure.

In some embodiments, a display panel may be, for example, an electroluminescent display panel, i.e. sub-pixels of the display panel include an electroluminescent device. The electroluminescent device may be, for example, an organic light emitting diode device or a quantum dot light emitting diode device.

The display apparatus provided by the embodiments of the present disclosure is: a mobile phone, a tablet computer, a television, a monitor, a notebook computer, a digital photo frame, a navigator and other products or components with a display function. Other essential components of the display apparatus should be understood by those of ordinary skill in the art, and will not be repeated here, nor should they be regarded as a limitation to the present disclosure. For implementation of the display apparatus, reference may be made to the embodiment of the above display panel, and repeated descriptions will not be repeated.

In conclusion, in the fingerprint recognition module and the driving method thereof and the display apparatus provided by embodiments of the present disclosure, the area of the second via holes of the fingerprint recognition module is increased, so that the distance between the edge of the orthographic projection of the region of the second via hole exposing the corresponding photoelectric converter on the base substrate and the edge of the orthographic projection of the surface of the corresponding photoelectric converter facing away from the base substrate on the base substrate is smaller than or equal to the first preset value. Correspondingly, the area of the first electrode may be increased, the area of the first electrode covering the corresponding photoelectric converter may thereby be increased, the coverage range of the electric field on the photoelectric converters may be enlarged, and the probability of the photo-generated carriers being captured by the defect states of the sidewalls of the photoelectric converters may be reduced, so that the problem of image image-sticking may be solved and an accuracy of fingerprint recognition may be improved.

While preferred embodiments of the present disclosure have been described, additional changes and modifications to these embodiments may be made by those of skill in the art once they are aware of basic inventive concepts. Therefore, the appended claims are intended to be construed to include the preferred embodiments and all changes and modifications that fall within the scope of the present disclosure.

Obviously, those of skill in the art can make various changes and modifications to the embodiments of the present disclosure without departing from the spirit and scope of the embodiments of the present disclosure. Thus, provided that these changes and modifications of the embodiments of the present disclosure fall within the scope of the claims of the present disclosure and their equivalents, the present disclosure is also intended to cover such changes and modifications.