CN113536988A - Ultrasonic fingerprint identification module, detection method thereof and display module - Google Patents
Ultrasonic fingerprint identification module, detection method thereof and display module Download PDFInfo
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- CN113536988A CN113536988A CN202110727428.6A CN202110727428A CN113536988A CN 113536988 A CN113536988 A CN 113536988A CN 202110727428 A CN202110727428 A CN 202110727428A CN 113536988 A CN113536988 A CN 113536988A
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Abstract
The invention discloses an ultrasonic fingerprint identification module, a detection method thereof and a display module, wherein the ultrasonic fingerprint identification module comprises a substrate, a driving circuit layer and an ultrasonic sensor layer, wherein the ultrasonic sensor layer is positioned on one side of the driving circuit layer, which is far away from the substrate, and comprises a first electrode layer, a piezoelectric material layer and a second electrode layer which are sequentially stacked, the first electrode layer comprises a plurality of first electrodes and detection electrodes, the first electrodes and the detection electrodes are mutually insulated, and the first electrodes are electrically connected with the driving circuit layer; the pin is electrically connected with the detection electrode; ultrasonic fingerprint identification module includes fingerprint identification district and peripheral zone, and detection electrode is located the fingerprint identification district, and the pin is located the peripheral zone. According to the invention, the detection electrode on the same layer as the first electrode is arranged in the fingerprint identification area, and the detection electrode is electrically connected with the pins in the peripheral area, so that the characteristics of the piezoelectric material at the first electrode can be accurately reflected, the usability of the detection result is higher, and the result is more accurate.
Description
Technical Field
The invention relates to the technical field of display, in particular to an ultrasonic fingerprint identification module, a detection method thereof and a display module.
Background
In recent years, with the rapid development of display technologies, display devices with biometric identification function gradually enter people's life and work, and fingerprint identification technology is widely applied to unlocking, secure payment and other applications by means of the characteristic that fingerprints have unique identities. The ultrasonic fingerprint identification technology is a new fingerprint identification technology at present, and can accurately identify fingerprints even if water stains and stains exist on the surfaces of the fingers, so that the ultrasonic fingerprint identification technology is concerned.
The piezoelectric property of the piezoelectric material in the ultrasonic fingerprint identification technology directly influences the capacity of converting an ultrasonic signal into an electric signal, and has a reference value for later-stage fingerprint signal acquisition, so that the piezoelectric property of the piezoelectric material is required to be detected when an ultrasonic fingerprint identification module is manufactured.
How to improve the detection precision of the piezoelectric material becomes a technical problem which needs to be solved urgently.
Disclosure of Invention
In view of this, the invention provides an ultrasonic fingerprint identification module, a detection method thereof and a display module, which are used for improving the detection precision of a piezoelectric material.
In one aspect, the present invention provides an ultrasonic fingerprint identification module, including:
a substrate base plate;
a driving circuit layer on the substrate;
the ultrasonic sensor layer is positioned on one side, away from the substrate base plate, of the driving circuit layer and comprises a first electrode layer, a piezoelectric material layer and a second electrode layer which are sequentially stacked, and the first electrode layer is positioned between the second electrode layer and the driving circuit layer; the first electrode layer comprises a plurality of first electrodes and detection electrodes, the first electrodes and the detection electrodes are insulated from each other, and the first electrodes are electrically connected with the driving circuit layer;
the pin is electrically connected with the detection electrode;
ultrasonic fingerprint identification module includes fingerprint identification district and peripheral zone, and detection electrode is located the fingerprint identification district, and the pin is located the peripheral zone.
Based on the same invention idea, the invention also provides a detection method applied to the ultrasonic fingerprint identification module, the ultrasonic fingerprint identification module comprises a fingerprint identification area and a peripheral area, and the detection method comprises the following steps:
providing a detection device;
providing a substrate base plate;
forming a driving circuit layer on a substrate;
forming a first electrode layer on one side of the driving circuit layer, which is far away from the substrate, patterning the first electrode layer to form a plurality of first electrodes and detection electrodes, wherein the first electrodes and the detection electrodes are insulated from each other, and the first electrodes are electrically connected with the driving circuit layer; the detection electrode is positioned in the fingerprint identification area;
forming a piezoelectric material layer on one side of the first electrode layer, which is far away from the substrate base plate;
forming a second electrode layer on one side of the piezoelectric material layer far away from the substrate base plate;
forming pins which are electrically connected with the detection electrodes and are positioned in the peripheral area;
one end of the detection device is electrically connected with the pin, and the other end of the detection device is electrically connected with the second electrode layer and used for detecting the piezoelectric property of the piezoelectric material layer positioned between the detection electrode and the second electrode layer.
Based on the same invention idea, the invention also provides a display module, which comprises a display panel and an ultrasonic fingerprint identification module positioned on one side of the display panel far away from the light emergent surface, wherein the ultrasonic fingerprint identification module is the fingerprint identification module.
Compared with the prior art, the ultrasonic fingerprint identification module, the detection method thereof and the display module provided by the invention at least realize the following beneficial effects:
in the prior art, the characteristics of the piezoelectric material in the peripheral area are usually detected, and since the characteristics of the piezoelectric material in the peripheral area cannot necessarily be reflected very accurately, the usability of the detection result is poor. The ultrasonic fingerprint identification module comprises an ultrasonic sensor layer positioned on one side of a driving circuit layer, which is far away from a substrate, wherein the ultrasonic sensor layer comprises a first electrode layer, a piezoelectric material layer and a second electrode layer which are sequentially stacked, the first electrode layer is positioned between the second electrode layer and the driving circuit, the first electrode layer comprises a plurality of first electrodes and detection electrodes, namely the detection electrodes and the first electrodes are formed by the same process on the same layer, the detection electrodes are positioned in a fingerprint identification area, the peripheral area comprises pins electrically connected with the detection electrodes, when the piezoelectric material layer is detected, only one end of a detection device is electrically connected with the pins, the other end of the detection device is connected with the second electrode layer to form a loop, the piezoelectric material layer between the detection electrodes and the second electrode layer can be tested after an electric signal is input into the detection circuit, and the detection electrodes are close to the first electrodes, therefore, the characteristics of the piezoelectric material in the fingerprint identification area and the area adjacent to the first electrode can be detected, the characteristics of the piezoelectric material at the first electrode can be accurately reflected, the usability of the detection result is high, and the result is accurate.
Of course, it is not necessary for any product in which the present invention is practiced to achieve all of the above-described technical effects simultaneously.
Other features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.
Fig. 1 is a schematic plan view of an ultrasonic fingerprint identification module provided in the prior art;
FIG. 2 is a cross-sectional view taken along line A-A' of FIG. 1;
FIG. 3 is a schematic diagram of a planar structure of the ultrasonic fingerprint recognition module according to the present invention;
FIG. 4 is a cross-sectional view taken along line B-B' of FIG. 3;
FIG. 5 is a schematic diagram of a planar structure of the ultrasonic fingerprint recognition module according to the present invention;
FIG. 6 is a cross-sectional view taken along line C-C' of FIG. 5;
FIG. 7 is a schematic diagram of a planar structure of another ultrasonic fingerprint identification module according to the present invention;
FIG. 8 is a schematic diagram of a planar structure of another ultrasonic fingerprint identification module according to the present invention;
FIG. 9 is a schematic diagram of a planar structure of another ultrasonic fingerprint identification module according to the present invention;
FIG. 10 is a flowchart illustrating a method for detecting an ultrasonic fingerprint recognition module according to the present invention;
FIG. 11 is a flowchart illustrating a method for detecting an ultrasonic fingerprint recognition module according to another embodiment of the present invention;
fig. 12 is a schematic plan view of a display module according to the present invention;
fig. 13 is a cross-sectional view taken along line D-D' of fig. 12.
Detailed Description
Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.
The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.
Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.
In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.
To ultrasonic fingerprint identification module among the prior art can only detect marginal area's piezoelectric material, the inventor has carried out following research to ultrasonic fingerprint identification module among the prior art: referring to fig. 1 and 2, fig. 1 is a schematic plan view illustrating an ultrasonic fingerprint recognition module provided in the prior art, and fig. 2 is a cross-sectional view taken along a direction a-a' in fig. 1. The ultrasonic fingerprint identification module in fig. 1 includes a fingerprint identification area and a peripheral area BB 'surrounding the fingerprint identification area AA', a pin 07 is disposed in the peripheral area BB ', the ultrasonic fingerprint identification module in fig. 2 includes a substrate 01, a driving circuit layer 02 on the substrate 01, and an ultrasonic sensor layer 03 on the driving circuit layer 02, the ultrasonic sensor layer 03 includes a first electrode 04, a piezoelectric material layer 05, and a second electrode 06 stacked in sequence, the first electrode 04 is electrically connected to the driving circuit layer 02, it can be seen from fig. 2 that the driving circuit layer 02 includes a transistor T', the transistor T 'includes a source S' and a drain D 'on the second metal layer, the drain D' is electrically connected to the first electrode 04, the pin 07 is made of the second metal layer, and when performing detection, two test probes of the detection apparatus are respectively connected to the pin 07 and the second electrode 06, since the pins 07 are disposed in the peripheral area BB ', the piezoelectric performance of the piezoelectric material layer 05 in the peripheral area BB ' is tested, and the piezoelectric performance of the piezoelectric material layer 05 in the fingerprint identification area AA ' cannot be tested, so that the fingerprint identification accuracy in the fingerprint identification area cannot be reflected.
In order to solve the above problems, the present invention provides an ultrasonic fingerprint identification module, a detection method thereof, and a display module, and specific embodiments thereof will be described in detail below.
Referring to fig. 3, 4, 5 and 6, fig. 3 is a schematic plane structure of an ultrasonic fingerprint recognition module provided by the present invention, fig. 4 is a sectional view along direction B-B 'in fig. 3, fig. 5 is a schematic plane structure of an ultrasonic fingerprint recognition module provided by the present invention, and fig. 6 is a sectional view along direction C-C' in fig. 5.
The ultrasonic fingerprint recognition module 100 in this embodiment includes:
a base substrate 1;
a drive circuit layer 2 on the base substrate 1;
the ultrasonic sensor layer 3 is positioned on one side, away from the substrate base plate 1, of the driving circuit layer 2 and comprises a first electrode 7 layer 4, a piezoelectric material layer 5 and a second electrode layer 6 which are sequentially stacked, and the first electrode 7 layer 4 is positioned between the second electrode layer 6 and the driving circuit layer 2; the first electrode 7 layer 4 comprises a plurality of first electrodes 7 and detection electrodes 8, the first electrodes 7 and the detection electrodes 8 are mutually insulated, and the first electrodes 7 are electrically connected with the driving circuit layer 2;
a pin 9 electrically connected to the detection electrode 8;
ultrasonic fingerprint identification module 100 includes fingerprint identification district AA and peripheral zone BB, and detection electrode 8 is located fingerprint identification district AA, and pin 9 is located peripheral zone BB.
Specifically, have fingerprint identification area AA and surround in the ultrasonic fingerprint identification module 100 that this embodiment provided peripheral zone BB of fingerprint identification area AA, have a plurality of fingerprint identification units in the fingerprint identification area AA and be used for producing the ultrasonic wave through piezoelectric material and discern fingerprint ridge or fingerprint valley, can be used for setting up drive circuit in the peripheral zone BB, fan-out is walked the line and is bound drive chip etc. for example drive circuit can be gate drive circuit VSR, be used for driving fingerprint identification's scanning line, fan-out is fingerprint identification's data line, be connected with the drive chip electricity that binds, drive chip provides the signal of telecommunication and reads the signal of telecommunication for fingerprint identification's data line.
Referring to fig. 4 and 6, the ultrasonic fingerprint identification module 100 includes a substrate base plate 1, a driving circuit layer 2 located on the substrate base plate 1, and an ultrasonic sensor layer 3 located on a side of the driving circuit layer 2 far from the substrate base plate 1, where the ultrasonic sensor layer 3 includes a first electrode 7 layer 4, a piezoelectric material layer 5, and a second electrode layer 6 stacked in sequence, and the first electrode 7 layer 4 is located between the second electrode layer 6 and the driving circuit layer 2; the first electrode 7 is electrically connected with the driving circuit layer 2; as shown in the figure, the driving circuit layer 2 may include a transistor T, the first electrode 7 is electrically connected to the transistor T in the driving circuit layer 2, so as to feed a high-frequency signal from the first electrode 7 to the piezoelectric material layer 5, and the corresponding second electrode may be connected to a fixed potential, so that the piezoelectric material layer 5 generates an ultrasonic wave according to an inverse piezoelectric effect under voltage oscillation across the first electrode 7 and the second electrode. It will be appreciated that the layer of piezoelectric material 5 may alternatively be: one or a combination of several of polyvinylidene fluoride, polyvinyl chloride and polyvinylidene fluoride copolymer.
It can be understood that piezoelectric material layer 5 can be two-layer, one of them layer is used for taking place ultrasonic signal, another layer is used for receiving the ultrasonic signal who reflects back, when the finger touches ultrasonic fingerprint identification module 100, piezoelectric material layer 5 launches ultrasonic signal to the contact surface earlier, because the air of filling is different between the contact surface of fingerprint ridge and fingerprint valley and ultrasonic fingerprint identification module 100 of finger, the acoustic impedance value that fingerprint ridge and fingerprint valley correspond the department is different, so the ultrasonic signal who reflects piezoelectric material layer 5 from the contact surface is also different, piezoelectric material layer 5 will connect the ultrasonic signal who receives to convert the electric signal into and convey to drive circuit layer 2, form the fingerprint identification image. Of course, the piezoelectric material layer 5 may be a layer, which controls the piezoelectric layer to generate and receive the ultrasonic signal in time division, and the specific number of layers of the piezoelectric material layer 5 is not specifically limited.
It should be noted that in order to realize more accurate fingerprint identification in the fingerprint identification area AA, the first electrodes 7 need to be arranged in the fingerprint identification area AA in an array, each first electrode 7 corresponds to one fingerprint identification unit, and fig. 3 and 5 only schematically show 10 rows and 10 columns of first electrodes 7, which of course does not represent the number of first electrodes 7 in an actual product.
Fig. 3 and 5 only schematically show the case where the detecting electrode 8 is one, and the detecting electrode 8 surrounds a plurality of first electrodes 7 arranged in an array, but the detecting electrode 8 may also be provided in a plurality, which is not shown here, fig. 3 and 5 show that there is a space between the first electrodes 7 and the detecting electrode 8, so as to achieve mutual insulation between the first electrodes 7 and the detecting electrode 8, in some alternative embodiments, the detecting electrode 8 may also be provided separately in the fingerprint identification area AA, and the detecting electrode 8 and the first electrode 7 do not overlap, so as to achieve mutual insulation, which is not specifically limited here.
The first electrode layer 4 comprises a plurality of first electrodes 7 and detection electrodes 8, and the first electrodes 7 and the detection electrodes 8 can be formed simultaneously in the same manufacturing process by a method of patterning the first electrode layer 4 during manufacturing, so that the thickness of the ultrasonic fingerprint identification module 100 is not increased, and the manufacturing process can be simplified.
Fig. 5 shows only the detecting electrodes 8 fully covering the fingerprint identification area AA, and fig. 3 shows only a part of the detecting electrodes 8 located in the fingerprint identification area AA, which is not limited in detail here.
In addition, since the second electrode is usually brought into contact with a fixed potential, the second electrode may be provided over the entire surface.
The lead 9 may be provided not on the same layer as the detection electrode 8 (see fig. 4), or may be provided on the same layer as the detection electrode 8 (see fig. 6), as long as the lead 9 is electrically connected to the detection electrode 8.
It can be understood that when the pin 9 and the detection electrode 8 are disposed on the same layer, the manufacturing process can be reduced, and in addition, when the pin 9 is electrically connected to the detection electrode 8 across the layer, a contact resistance is generated, and simultaneously, when the pin 9 is electrically connected to the detection electrode 8 across the layer, a parasitic capacitance is also generated, and the pin 9 and the detection electrode 8 on the same layer can avoid generating the contact resistance and introducing the parasitic capacitance.
When detecting, the detecting device can input an electric signal through the pin 9 and the second electrode layer 6, because the pin 9 is electrically connected with the detecting electrode 8, and the detecting electrode 8 is located in the fingerprint identification area AA, when a signal is applied to the pin 9 and the second electrode layer 6, the piezoelectric property of the piezoelectric material layer 5 between the detecting electrode 8 and the second electrode layer 6 in the fingerprint identification area AA is detected, and the fingerprint identification performance can be embodied better. Since the detection electrode 8 is closer to the first electrode 7, the characteristics of the piezoelectric material in the area adjacent to the first electrode 7 in the fingerprint identification area AA can be detected, so that the characteristics of the piezoelectric material at the first electrode 7 can be accurately reflected, the detection result has high referenceability, and the result is accurate.
Compared with the prior art, the ultrasonic fingerprint identification module 100 of the embodiment at least has the following beneficial effects:
in the prior art, the characteristics of the piezoelectric material in the peripheral area are usually detected, and since the characteristics of the piezoelectric material in the peripheral area cannot necessarily be reflected very accurately, the usability of the detection result is poor. The ultrasonic fingerprint identification module 100 comprises an ultrasonic sensor layer 3 positioned on one side, away from a substrate 1, of a driving circuit layer 2, wherein the ultrasonic sensor layer 3 comprises a first electrode layer 4, a piezoelectric material layer 5 and a second electrode layer 6 which are sequentially stacked, the first electrode layer 4 is positioned between the second electrode layer 6 and a driving circuit, the first electrode layer 4 comprises a plurality of first electrodes 7 and detection electrodes 8, namely the detection electrodes 8 and the first electrodes 7 are formed in the same layer and the same process, the detection electrodes 8 are positioned in a fingerprint identification area AA, and a peripheral area BB comprises pins 9 electrically connected with the detection electrodes 8; on the other hand, since the pin 9 is electrically connected to the detection electrode 8 and the detection electrode 8 is located in the fingerprint identification area AA, when a signal is applied to the pin 9 and the second electrode layer 6, the piezoelectric performance of the piezoelectric material layer 5 between the detection electrode 8 and the second electrode layer 6 in the fingerprint identification area AA is detected, and since the detection electrode 8 is closer to the first electrode 7, the characteristics of the piezoelectric material in the fingerprint identification area AA adjacent to the first electrode 7 can be detected, so that the characteristics of the piezoelectric material at the first electrode 7 can be accurately reflected, the usability of the detection result is high, and the result is accurate.
In some alternative embodiments, with continued reference to fig. 3 and 5, a plurality of first electrodes 7 are arranged in an array.
In order to realize that the fingerprint identification area AA can identify fingerprints more accurately, the first electrodes 7 may be arranged in the fingerprint identification area AA in an array, and each first electrode 7 corresponds to one fingerprint identification unit, so as to improve the accuracy of fingerprint identification, and of course, the greater the number of the first electrodes 7, the higher the accuracy of fingerprint identification is.
In this embodiment, the plurality of first electrodes 7 are arranged in an array, which can improve the accuracy of fingerprint identification.
In some alternative embodiments, with continued reference to fig. 3 and 5, the detection electrode 8 includes a plurality of openings 10, with the first electrode 7 being located within the openings 10.
Specifically, the detection electrode 8 and the first electrode 7 are both located in the fingerprint identification area AA, the first electrode 7 is arranged in the fingerprint identification area AA in an array manner, the detection electrode 8 is provided with a plurality of openings 10, the first electrode 7 is located in the openings 10, and a gap is formed between the first electrode 7 and the detection electrode 8, so that the first electrode 7 and the detection electrode 8 are insulated.
Since the pin 9 is electrically connected to the detecting electrode 8, and the detecting electrode 8 is located in the fingerprint identification area AA, when a signal is applied to the pin 9 and the second electrode layer 6, the piezoelectric property of the piezoelectric material layer 5 between the detecting electrode 8 and the second electrode layer 6 in the fingerprint identification area AA is detected. Since the detection electrode 8 is closer to the first electrode 7, the characteristics of the piezoelectric material in the area adjacent to the first electrode 7 in the fingerprint identification area AA can be detected, so that the characteristics of the piezoelectric material at the first electrode 7 can be accurately reflected, and the detection result has high usability and accurate result.
In some alternative embodiments, with continued reference to fig. 3 and 5, the number of detection electrodes 8 is one and the number of pins 9 is one.
It can be understood that fig. 3 only shows that one detecting electrode 8 is located in a part of the fingerprint identification area AA, fig. 5 only shows that one detecting electrode 8 is fully distributed in the fingerprint identification area AA, the detecting electrode 8 is electrically connected with the pin 9 correspondingly, since the pin 9 is electrically connected with the detecting electrode 8 and the detecting electrode 8 is located in the fingerprint identification area AA, when a signal is applied to the pin 9 and the second electrode layer 6, the detected piezoelectric property of the piezoelectric material layer 5 between the detecting electrode 8 and the second electrode layer 6 in the fingerprint identification area AA is detected, since the detecting electrode 8 is closer to the first electrode 7, the property of the piezoelectric material in the fingerprint identification area AA adjacent to the first electrode 7 can be detected, and then the property of the piezoelectric material at the first electrode 7 can be accurately reflected, the usability of the detection result is higher, and the result is accurate.
Certainly, the manufacturing process for arranging one detection electrode 8 is simpler, the detection electrode 8 and the first electrode 7 can be formed by arranging the first electrode layer 4 on the whole surface and then patterning the detection electrode layer, and the manufacturing process is simpler.
In some alternative embodiments, referring to fig. 7, fig. 7 is a schematic plan view of another ultrasonic fingerprint identification module 100 provided in the present invention. The number of the detection electrodes 8 is multiple, the number of the pins 9 is multiple, and the detection electrodes 8 are electrically connected with the pins 9 in a one-to-one correspondence manner.
Only the case where the lead pins 9 are provided in the same layer as the detection electrodes 8 is shown in fig. 7. Fig. 7 only schematically shows that there are 5 detection electrodes 8, and the detection electrodes 8 are strip-shaped electrodes, and 5 pins 9 are correspondingly disposed, although the number and shape of the detection electrodes 8 are not specifically limited here.
In this embodiment, the number of the detection electrodes 8 is multiple, the number of the pins 9 is multiple, and the detection electrodes 8 are electrically connected to the pins 9 in a one-to-one correspondence manner, so that the piezoelectric properties of piezoelectric materials at different positions in the fingerprint identification area AA can be detected, and the piezoelectric properties of the piezoelectric materials can be more accurately reflected, because the detection electrodes 8 are closer to the first electrode 7, the characteristics of the piezoelectric materials in the fingerprint identification area AA and in the area adjacent to the first electrode 7 can be detected, and therefore the characteristics of the piezoelectric materials at the first electrode 7 can be accurately reflected, and the detection result has high availability and accurate result. Of course, the greater the number of detection electrodes 8, the more accurate the detection.
In some alternative embodiments, with continuing reference to fig. 7, and with reference to fig. 8 and 9, fig. 8 is a schematic plan view of another ultrasonic fingerprint identification module 100 provided by the present invention, and fig. 9 is a schematic plan view of another ultrasonic fingerprint identification module 100 provided by the present invention. The detection electrodes 8 are strip-shaped, and a plurality of detection electrodes 8 are arranged in a row; or, the detecting electrodes 8 are block-shaped, and the detecting electrodes 8 are arranged in an array; or, the plurality of detection electrodes 8 include 1 st to nth detection electrodes 8, n is a positive integer greater than or equal to 2, the 1 st detection electrode 8 is rectangular, the 2 nd to nth detection electrodes 8 are all L-shaped structures, and two branches of the L-shaped structures extend along the first direction and the second direction respectively; the 1 st to nth detection electrodes 8 are arranged in sequence, and the detection electrode 8 of the L-shaped structure covers the previous detection electrode 8 in both the first direction and the second direction, and the first direction intersects with the second direction.
Fig. 7 shows that 5 detection electrodes 8 are strip-shaped electrodes, 5 pins 9 are disposed in the peripheral area BB, the pins 9 are electrically connected to the strip-shaped detection electrodes 8 in a one-to-one correspondence manner, the pins 9 and the detection electrodes 8 are disposed on the same layer, and the number of the detection electrodes 8 is not specifically limited; fig. 8 shows that 4 detection electrodes 8 are block-shaped electrodes, which are arranged in an array, and 4 pins 9 are disposed in the peripheral region BB, the pins 9 are electrically connected to the block-shaped detection electrodes 8 in a one-to-one correspondence, the pins 9 are disposed on the same layer as the block-shaped detection electrodes 8, and the number of the detection electrodes 8 is not specifically limited; fig. 9 shows that the plurality of detection electrodes 8 include 1 st to 5 th detection electrodes 8, although the value of n is not specifically limited herein as long as n is a positive integer greater than or equal to 2, in fig. 9, the 1 st detection electrode 8 is rectangular, and the 2 nd to 5 th detection electrodes 8 are all L-shaped structures, and two branches of the L-shaped structures extend along the first direction and the second direction, respectively; the 1 st to 5 th detection electrodes 8 are sequentially arranged, and the detection electrode 8 with the L-shaped structure covers the previous detection electrode 8 in both the first direction and the second direction, where the first direction and the second direction are perpendicular to each other, and the pins 9 and the detection electrodes 8 may be disposed in the same layer.
The structures in fig. 7 to 9 all enable the plurality of detection electrodes 8 to be uniformly arranged in the fingerprint identification area AA, so that the piezoelectric properties of piezoelectric materials at different positions in the fingerprint identification area AA can be detected, and the piezoelectric properties of the piezoelectric materials at each position in the fingerprint identification area AA can be more accurately reflected, because the detection electrodes 8 are closer to the first electrode 7, the characteristics of the piezoelectric materials at the area adjacent to the first electrode 7 in the fingerprint identification area AA can be detected, so that the characteristics of the piezoelectric materials at the first electrode 7 can be accurately reflected, the usability of the detection result is higher, and the result is accurate. Of course, the greater the number of detection electrodes 8, the more accurate the detection.
In addition, fig. 7 to 9 only illustrate three design schemes of the distribution of the detection electrodes, it should be noted that, in the fingerprint identification area AA, the detection electrodes may be arranged correspondingly according to the positions of the piezoelectric materials to be detected, and the arrangement mode of the pins may also be adjusted according to the requirements.
In some alternative embodiments, with continued reference to fig. 4 and 6, the driving layer includes a driving circuit including a transistor T, the transistor T includes an active layer 11 located on one side of the substrate base plate 1, a first metal layer located on one side of the active layer 11 away from the substrate base plate 1, a second metal layer located on one side of the first metal layer away from the substrate base plate 1, an insulating layer 12 is included among the active layer 11, the first metal layer, and the second metal layer is electrically connected to the first sub-electrode through a via hole.
Specifically, referring to fig. 4 and 6, a buffer layer 13 is disposed on one side of the substrate 1, an active layer 11 is disposed on one side of the buffer layer 13 away from the substrate 1, the active layer 11 is a semiconductor of the transistor T, a first metal layer is disposed on one side of the active layer 11 away from the substrate 1, the first metal layer is a gate G of the transistor T, a second metal layer is disposed on one side of the first metal layer away from the substrate 1, the second metal layer is a source S and a drain D of the transistor T, an insulating layer 12 is disposed between the active layer 11, the first metal layer, and the second metal layer, and the buffer layer 13 and the insulating layer 12 are not filled with patterns in the drawing, and the first electrode 7 is electrically connected to the drain D of the second metal layer through a via hole, so that the first electrode 7 is driven by the transistor T to supply a high-frequency signal from the first electrode 7 to the piezoelectric material layer 5, and a corresponding second electrode can be connected to a fixed potential, so that the piezoelectric material layer 5 generates ultrasonic waves according to the inverse piezoelectric effect under the voltage oscillation across the first electrode 7 and the second electrode.
In some alternative embodiments, with continued reference to fig. 3-9, the material of the first electrode layer 4 comprises indium tin oxide and the material of the second electrode layer 6 comprises silver, nickel, or titanium.
It can be understood that the first electrode layer 4 needs to have conductivity, the material may be selected from indium tin oxide for the driving electrode layer, and the second electrode layer 6 also has conductivity, and since the second electrode layer 6 is located at the uppermost layer, it needs to have a certain oxidation resistance to prevent the second electrode layer 6 from being affected by oxidation to generate an ultrasonic signal, where the second electrode layer 6 may be made of oxidation resistant metals such as silver, nickel, or titanium, and certainly, optionally, a conductive silver paste may be used during manufacturing.
In this embodiment, the material of the first electrode 7 includes indium tin oxide, and the material of the second electrode layer 6 includes silver, nickel, or titanium, so that after the first electrode layer 4 and the second electrode layer 6 are energized, the piezoelectric material layer 5 between the first electrode layer 4 and the second electrode layer 6 uploads an ultrasonic signal, thereby implementing fingerprint identification.
Based on the same idea, the present invention further provides a detection method applied to any one of the ultrasonic fingerprint identification modules 100 shown in fig. 3 to 9, where the ultrasonic fingerprint identification module includes a fingerprint identification area and a peripheral area, with reference to fig. 10, fig. 10 is a flowchart of a detection method of an ultrasonic fingerprint identification module provided by the present invention, and the detection method shown in fig. 10 includes:
s1, providing a detection device;
s2, providing a substrate base plate;
s3, forming a driving circuit layer on the substrate;
s4, forming a first electrode layer on one side of the driving circuit layer, which is far away from the substrate, patterning the first electrode layer to form a plurality of first electrodes and detection electrodes, wherein the first electrodes and the detection electrodes are insulated from each other, and the first electrodes are electrically connected with the driving circuit layer; the detection electrode is positioned in the fingerprint identification area;
s5, forming pins which are electrically connected with the detection electrodes and are positioned in the peripheral area;
s6, forming a piezoelectric material layer on one side of the first electrode layer far away from the substrate base plate;
s7, forming a second electrode layer on the side, away from the substrate, of the piezoelectric material layer;
and S8, electrically connecting one end of the detection device with the pin and the other end with the second electrode layer, and detecting the piezoelectric property of the piezoelectric material layer between the detection electrode and the second electrode layer.
Piezoelectric materials have piezoelectricity, dielectricity, and pyroelectricity. The present invention mainly detects the piezoelectric characteristics of the piezoelectric material layer 5, such as detecting the resonant frequency, impedance performance, current-voltage characteristics, resistance, capacitance, inductance, etc., and is not limited specifically here, taking the detection of the resonant frequency of the piezoelectric material layer 5 in the fingerprint identification area AA as an example, the voltage input to the first electrode 7 (e.g., 10V) and the second electrode 8(0V) is constant, the electrical signals are sequentially input from low frequency to high frequency, and the corresponding frequency is the resonant frequency when the ultrasonic signal output by the piezoelectric material layer 5 is the strongest.
With reference to fig. 3 to 9, in the present invention, since the pin 9 is electrically connected to the detection electrode 8, and the detection electrode 8 is located in the fingerprint identification area, when a signal is applied to the pin 9 and the second electrode layer 6, the piezoelectric performance of the piezoelectric material layer 5 between the detection electrode 8 and the second electrode layer 6 in the fingerprint identification area is detected, and since the detection electrode 8 is closer to the first electrode 7, the characteristics of the piezoelectric material in the area adjacent to the first electrode 7 in the fingerprint identification area AA can be detected, so that the characteristics of the piezoelectric material at the first electrode 7 can be accurately reflected, and the usability of the detection result is high, and the result is accurate.
In some optional embodiments, referring to fig. 11, fig. 11 is a flowchart of a detection method of an ultrasonic fingerprint identification module according to still another embodiment of the present invention, where before S5 in fig. 11, after forming a piezoelectric material layer on a side of the first electrode layer away from the substrate, the method further includes S9: two ends of the detection device are respectively and electrically connected with any two pins and used for detecting the piezoelectric property of the piezoelectric material layer positioned between the two detection electrodes.
After the piezoelectric material layer 5 is formed and before the second electrode layer 6 is formed, two ends of the detection device are respectively electrically connected with any two pins 9, and voltages input by the two pins 9 are unequal, so that the piezoelectric characteristics of the piezoelectric material layer 5 between any two detection electrodes 8 electrically connected with the pins 9 correspondingly can be detected, and the characteristics of the piezoelectric material in the area adjacent to the first electrode 7 in the fingerprint identification area AA can be detected because the detection electrodes 8 are closer to the first electrode 7, so that the characteristics of the piezoelectric material between the two first electrodes 7 can be accurately reflected, and the usability of the detection result is high and the result is accurate.
In the detection method in this embodiment, any two pins 9 are electrically connected to two ends of the detection device, so that the piezoelectric property of the piezoelectric material layer 5 between any two detection electrodes 8 in the fingerprint identification area AA can be correspondingly detected, the property of the piezoelectric material between two first electrodes 7 can be accurately reflected, and the detection result has high availability and accurate result.
Referring to fig. 12 and 13, fig. 12 is a schematic plan view of a display module according to the present invention, and fig. 13 is a cross-sectional view taken along direction D-D' of fig. 12. The display module 1000 includes the display panel 200 and is located the ultrasonic fingerprint identification module 100 that the display panel 200 keeps away from the light surface OU one side, certainly fingerprint identification module 100 here is the ultrasonic fingerprint identification module 100 of any embodiment in above-mentioned fig. 3 to fig. 9, only schematically show in fig. 13 that the fingerprint identification district reuses as a part in the display area of display panel, certainly the fingerprint identification district also can be the display area of whole display panel 200 for realize fingerprint identification, certainly display module here has the beneficial effect of the ultrasonic fingerprint identification module of above arbitrary embodiment, do not describe here any more. The display panel may be a liquid crystal display panel or an organic electroluminescent self-emitting display panel.
According to the embodiment, the ultrasonic fingerprint identification module, the detection method thereof and the display module at least realize the following beneficial effects:
in the prior art, the characteristics of the piezoelectric material in the peripheral area are usually detected, and since the characteristics of the piezoelectric material in the peripheral area cannot necessarily be reflected very accurately, the usability of the detection result is poor. The ultrasonic fingerprint identification module comprises an ultrasonic sensor layer positioned on one side of a driving circuit layer, which is far away from a substrate, wherein the ultrasonic sensor layer comprises a first electrode layer, a piezoelectric material layer and a second electrode layer which are sequentially stacked, the first electrode layer is positioned between the second electrode layer and the driving circuit, the first electrode layer comprises a plurality of first electrodes and detection electrodes, namely the detection electrodes and the first electrodes are formed by the same process on the same layer, the detection electrodes are positioned in a fingerprint identification area, the peripheral area comprises pins electrically connected with the detection electrodes, when the piezoelectric material layer is detected, only one end of a detection device is electrically connected with the pins, the other end of the detection device is connected with the second electrode layer to form a loop, the piezoelectric material layer between the detection electrodes and the second electrode layer can be tested after an electric signal is input into the detection circuit, and therefore, the piezoelectric property of the piezoelectric material layer in the fingerprint identification area can be accurately tested, the detection electrode is close to the first electrode, so that the characteristics of the piezoelectric material in the fingerprint identification area and in the area adjacent to the first electrode can be detected, the characteristics of the piezoelectric material in the first electrode can be accurately reflected, the usability of the detection result is high, and the result is accurate.
Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustrative purposes only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.
Claims (11)
1. The utility model provides an ultrasonic fingerprint identification module which characterized in that includes:
a substrate base plate;
the driving circuit layer is positioned on the substrate base plate;
the ultrasonic sensor layer is positioned on one side, away from the substrate base plate, of the driving circuit layer and comprises a first electrode layer, a piezoelectric material layer and a second electrode layer which are sequentially stacked, and the first electrode layer is positioned between the second electrode layer and the driving circuit layer; the first electrode layer comprises a plurality of first electrodes and detection electrodes, the first electrodes and the detection electrodes are insulated from each other, and the first electrodes are electrically connected with the driving circuit layer;
the pin is electrically connected with the detection electrode;
the ultrasonic fingerprint identification module comprises a fingerprint identification area and a peripheral area, the detection electrode is located in the fingerprint identification area, and the pin is located in the peripheral area.
2. The ultrasonic fingerprint identification module of claim 1,
the plurality of first electrodes are arranged in an array.
3. The ultrasonic fingerprint identification module of claim 1,
the detection electrode includes a plurality of openings, and the first electrode is located within the openings.
4. The ultrasonic fingerprint identification module of claim 1,
the number of the detection electrodes is one, and the number of the pins is one.
5. The ultrasonic fingerprint identification module of claim 1,
the number of the detection electrodes is multiple, the number of the pins is multiple, and the detection electrodes are electrically connected with the pins in a one-to-one correspondence mode.
6. The ultrasonic fingerprint identification module of claim 5,
the detection electrodes are strip-shaped, and a plurality of detection electrodes are arranged in a row;
or, the detection electrodes are blocky, and a plurality of detection electrodes are arranged in an array;
or the plurality of detection electrodes comprise 1 st to nth detection electrodes, n is a positive integer greater than or equal to 2, the 1 st detection electrode is rectangular, the 2 nd to nth detection electrodes are all in an L-shaped structure, and two branches of the L-shaped structure extend along a first direction and a second direction respectively; the 1 st to nth detection electrodes are arranged in sequence, and the detection electrode of the L-shaped structure covers the previous detection electrode in both the first direction and the second direction, and the first direction intersects with the second direction.
7. The module of claim 1, wherein the driving layer comprises a driving circuit, the driving circuit comprises a transistor, the transistor comprises an active layer on one side of the substrate, a first metal layer on one side of the active layer away from the substrate, and a second metal layer on one side of the first metal layer away from the substrate, the active layer, the first metal layer, and the second metal layer each comprise an insulating layer therebetween, and the second metal layer is electrically connected to the first sub-electrode through a via.
8. The ultrasonic fingerprint identification module of claim 1, wherein the material of the first electrode layer comprises indium tin oxide, and the material of the second electrode layer comprises silver, nickel, or titanium.
9. A detection method applied to the ultrasonic fingerprint identification module according to any one of claims 1 to 8, wherein the ultrasonic fingerprint identification module comprises a fingerprint identification area and a peripheral area, and the detection method comprises:
providing a detection device;
providing a substrate base plate;
forming a driving circuit layer on the substrate base plate;
forming a first electrode layer on one side of the driving circuit layer, which is far away from the substrate, patterning the first electrode layer to form a plurality of first electrodes and detection electrodes, wherein the first electrodes and the detection electrodes are insulated from each other, and the first electrodes are electrically connected with the driving circuit layer; the detection electrode is positioned in the fingerprint identification area;
forming pins which are electrically connected with the detection electrodes and are positioned in the peripheral area;
forming a piezoelectric material layer on one side of the first electrode layer far away from the substrate base plate;
forming a second electrode layer on one side of the piezoelectric material layer far away from the substrate base plate;
one end of the detection device is electrically connected with the pin, and the other end of the detection device is electrically connected with the second electrode layer and used for detecting the piezoelectric property of the piezoelectric material layer between the detection electrode and the second electrode layer.
10. The method for detecting the ultrasonic fingerprint identification module according to claim 9, further comprising, after forming a piezoelectric material layer on a side of the first electrode layer away from the substrate, a step of: and two ends of the detection device are respectively and electrically connected with any two pins and used for detecting the piezoelectric property of the piezoelectric material layer between the two detection electrodes.
11. The utility model provides a display module assembly, its characterized in that includes display panel and is located display panel keeps away from the ultrasonic fingerprint identification module of plain noodles one side, the fingerprint identification module is the ultrasonic fingerprint identification module of any of claims 1 to 8.
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