CN111782090B - Display module, ultrasonic touch detection method and ultrasonic fingerprint identification method - Google Patents
Display module, ultrasonic touch detection method and ultrasonic fingerprint identification method Download PDFInfo
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- CN111782090B CN111782090B CN202010618848.6A CN202010618848A CN111782090B CN 111782090 B CN111782090 B CN 111782090B CN 202010618848 A CN202010618848 A CN 202010618848A CN 111782090 B CN111782090 B CN 111782090B
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- 229910052451 lead zirconate titanate Inorganic materials 0.000 description 2
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
- G06F3/043—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means using propagating acoustic waves
- G06F3/0433—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means using propagating acoustic waves in which the acoustic waves are either generated by a movable member and propagated within a surface layer or propagated within a surface layer and captured by a movable member
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G06V40/00—Recognition of biometric, human-related or animal-related patterns in image or video data
- G06V40/10—Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
- G06V40/12—Fingerprints or palmprints
- G06V40/13—Sensors therefor
- G06V40/1306—Sensors therefor non-optical, e.g. ultrasonic or capacitive sensing
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- Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)
Abstract
The invention relates to a display module, which comprises a display panel and further comprises: the ultrasonic sensor is used for sending ultrasonic waves, receiving reflected ultrasonic waves and converting the reflected ultrasonic waves into electric signals; the touch detection module is used for obtaining the finger touch position according to the electric signal in a touch detection mode so as to perform touch detection; and the fingerprint identification module is used for carrying out fingerprint identification according to the electric signal in a fingerprint identification mode. The invention also relates to an ultrasonic touch detection method and an ultrasonic fingerprint identification method.
Description
Technical Field
The invention relates to the technical field of display product manufacturing, in particular to a display module, an ultrasonic touch detection method and an ultrasonic fingerprint identification method.
Background
In the display device having both the touch detection function and the fingerprint recognition function, the touch detection structure and the fingerprint recognition structure are generally set independently of each other, which increases the cost and increases the thickness of the display device.
Disclosure of Invention
In order to solve the technical problems, the invention provides a display module, an ultrasonic touch detection method and an ultrasonic fingerprint identification method, which solve the problems that touch detection and fingerprint identification are separately and independently arranged, so that the cost is increased and the thickness is increased.
In order to achieve the above purpose, the technical scheme adopted by the embodiment of the invention is as follows: the utility model provides a display module assembly, includes display panel, still includes:
the ultrasonic sensor is arranged on the non-display side of the display panel and is used for transmitting ultrasonic waves, receiving reflected ultrasonic waves and converting the reflected ultrasonic waves into electric signals;
the touch detection module is arranged on the non-display side of the display panel, connected with the ultrasonic sensor and used for obtaining a finger touch position according to the electric signal in a touch detection mode so as to perform touch detection;
and the fingerprint identification module is arranged on the non-display side of the display panel, is connected with the ultrasonic sensor and is used for carrying out fingerprint identification according to the electric signal in a fingerprint identification mode.
Optionally, the ultrasonic sensor includes a piezoelectric film layer, and a transmitting electrode layer and a receiving electrode layer located at opposite sides of the piezoelectric film layer;
In the ultrasonic wave transmitting stage, the transmitting electrode layer receives an electric signal, and the piezoelectric film layer generates ultrasonic waves; in the ultrasonic wave receiving stage, ultrasonic waves are transmitted to the light emitting surface of the display panel and are reflected and then converted into electric signals by the piezoelectric film layer, and the receiving electrode layer receives the electric signals and transmits the electric signals to the fingerprint identification module or the touch detection module.
Optionally, the emitter electrode layer includes a plurality of rows of stripe-shaped emitter electrodes arranged along a first direction, the receiver electrode layer includes a plurality of block-shaped receiver electrodes arranged in an array, a front projection of the receiver electrode on the emitter electrode layer is located on the stripe-shaped emitter electrode, and a front projection of each receiver electrode on the display panel covers at least one pixel area.
Optionally, the receiving electrode layer further includes a thin film transistor connected to the receiving electrode, the touch detection module is connected to the thin film transistor through a reading signal line to perform touch detection, and the fingerprint identification module is connected to the thin film transistor through a reading signal line to perform fingerprint identification.
Optionally, a metal electrode layer made of metal Ag is disposed on a side of the emitter electrode layer away from the piezoelectric film layer, an insulating layer is disposed between the metal electrode layer and the emitter electrode layer, and an insulating protection layer is disposed on a side of the metal electrode layer away from the piezoelectric film layer.
Optionally, an insulating layer is disposed on a side of the emitter electrode layer away from the piezoelectric film layer, and an absolute value of a difference between a density of an insulating material used for the insulating layer and a density of the metal Ag is smaller than a preset value.
The embodiment of the invention also provides an ultrasonic touch detection method which is applied to the display module and comprises the following steps:
controlling an ultrasonic sensor to send ultrasonic waves;
controlling an ultrasonic sensor to receive the reflected ultrasonic wave and converting the ultrasonic wave into an electric signal;
and obtaining the touch position of the finger according to the electric signal so as to perform touch detection.
Optionally, the display module assembly includes the following steps:
applying a high-frequency signal to a first row of strip-shaped emission electrodes in the plurality of rows of strip-shaped emission electrodes, wherein the voltage of the strip-shaped emission electrodes outside the first row of strip-shaped emission electrodes is zero, so that the piezoelectric film layer generates ultrasonic waves;
the piezoelectric film layer receives the reflected ultrasonic wave and converts the ultrasonic wave into an electric signal;
orthographic projection on the emitting electrode layer is positioned on a plurality of receiving electrodes above the first row of strip-shaped emitting electrodes, receives the electric signals, and is read by corresponding reading signal lines after being processed by corresponding thin film transistors;
And finishing touch scanning line by line according to the steps, and judging the touch position of the finger according to the fact that the energy of a signal reflected back by the area with the finger touch is smaller than that of a signal reflected back by the area without the finger touch.
Optionally, the display module assembly includes the following steps:
dividing a plurality of rows of strip-shaped emission electrodes into a plurality of electrode groups, wherein each electrode group comprises an odd number of strip-shaped emission electrodes, and the number of the strip-shaped emission electrodes included in each electrode group is more than or equal to 3;
carrying out phase focusing on a plurality of strip-shaped emission electrodes in a first electrode group in a plurality of electrode groups by utilizing a focusing wave forming principle, so that ultrasonic waves generated by applying high-frequency signals to the plurality of strip-shaped emission electrodes in the first electrode group are converged and overlapped in a first area of a light-emitting surface of a display panel, wherein the first area is an area covered by orthographic projection of the focusing electrode on the display panel, and the focusing electrode is a strip-shaped emission electrode positioned in the central position in the first electrode group;
a plurality of receiving electrodes positioned on the focusing electrode are orthographically projected on the transmitting electrode layer, and the receiving electrodes receive the electric signals and are read by corresponding reading signal lines after being processed by corresponding thin film transistors;
And carrying out phase focusing on other electrode groups except the first electrode group in sequence according to the steps to finish touch scanning, and judging the touch position of the finger according to the fact that the energy of a signal reflected back by the area with the finger touch is smaller than that of a signal reflected back by the area without the finger touch.
Optionally, the forming principle of the focusing wave is utilized to perform phase focusing on a plurality of strip-shaped emitting electrodes in a first electrode group in the plurality of electrode groups, so that ultrasonic waves generated by applying high-frequency signals to the plurality of strip-shaped emitting electrodes in the first electrode group are converged and overlapped in a first area of a light-emitting surface of the display panel; the method specifically comprises the following steps:
setting a strip-shaped transmitting electrode positioned at the central position in a first electrode group as a focusing electrode, and applying high-frequency signals to a plurality of strip-shaped transmitting electrodes according to a preset time sequence so that generated ultrasonic waves are converged and overlapped in the first area;
the preset time sequence comprises the steps of sequentially applying high-frequency signals along a first direction from the strip-shaped emitting electrodes positioned at the edge positions of the first electrode group to the strip-shaped emitting electrodes positioned at the center positions of the first electrode group, and simultaneously applying the high-frequency signals to each pair of strip-shaped emitting electrodes symmetrically arranged at the two sides of the focusing electrode.
The embodiment of the invention also provides an ultrasonic fingerprint identification method which is applied to the display module and comprises the following steps:
controlling an ultrasonic sensor to send ultrasonic waves;
controlling an ultrasonic sensor to receive the reflected ultrasonic wave and converting the ultrasonic wave into an electric signal;
and fingerprint identification is carried out according to the electric signals.
Optionally, the display module assembly includes the following steps:
applying a high-frequency signal to a first row of strip-shaped emission electrodes in the plurality of rows of strip-shaped emission electrodes, wherein the voltage of the strip-shaped emission electrodes outside the first row of strip-shaped emission electrodes is zero, so that the piezoelectric film layer generates ultrasonic waves;
the piezoelectric film layer receives the reflected ultrasonic wave and converts the ultrasonic wave into an electric signal;
orthographic projection on the emitting electrode layer is positioned on a plurality of receiving electrodes above the first row of strip-shaped emitting electrodes, receives the electric signals, and is read by corresponding reading signal lines after being processed by corresponding thin film transistors;
touch scanning is completed row by row according to the steps, and fingerprint information is identified according to different energy of signals reflected by the ridges of the finger.
Optionally, the display module assembly includes the following steps:
dividing a plurality of rows of strip-shaped emission electrodes into a plurality of electrode groups, wherein each electrode group comprises an odd number of strip-shaped emission electrodes, and the number of the strip-shaped emission electrodes included in each electrode group is more than or equal to 3;
Carrying out phase focusing on a plurality of strip-shaped emission electrodes in a first electrode group in a plurality of electrode groups by utilizing a focusing wave forming principle, so that ultrasonic waves generated by applying high-frequency signals to the plurality of strip-shaped emission electrodes in the first electrode group are converged and overlapped in a first area of a light-emitting surface of a display panel, wherein the first area is an area covered by orthographic projection of the focusing electrode on the display panel, and the focusing electrode is a strip-shaped emission electrode positioned in the central position in the first electrode group;
a plurality of receiving electrodes positioned on the focusing electrode are orthographically projected on the transmitting electrode layer, and the receiving electrodes receive the electric signals and are read by corresponding reading signal lines after being processed by corresponding thin film transistors;
and carrying out phase focusing on other electrode groups except the first electrode group in sequence according to the steps to finish scanning, and identifying fingerprint information according to different energy of signals reflected by the ridges of the finger.
Optionally, the forming principle of the focusing wave is utilized to perform phase focusing on a plurality of strip-shaped emitting electrodes in a first electrode group in the plurality of electrode groups, so that ultrasonic waves generated by applying high-frequency signals to the plurality of strip-shaped emitting electrodes in the first electrode group are converged and overlapped in a first area of a light-emitting surface of the display panel; the method specifically comprises the following steps:
Setting a strip-shaped transmitting electrode positioned at the central position in a first electrode group as a focusing electrode, and applying high-frequency signals to a plurality of strip-shaped transmitting electrodes according to a preset time sequence so that generated ultrasonic waves are converged and overlapped in the first area;
the preset time sequence comprises the steps of sequentially applying high-frequency signals along a first direction from the strip-shaped emitting electrodes positioned at the edge positions of the first electrode group to the strip-shaped emitting electrodes positioned at the center positions of the first electrode group, and simultaneously applying the high-frequency signals to each pair of strip-shaped emitting electrodes symmetrically arranged at the two sides of the focusing electrode.
The beneficial effects of the invention are as follows: the touch detection and fingerprint identification are integrated, the functions of touch detection and fingerprint identification are realized by utilizing ultrasonic waves, touch structures such as a touch panel are not required to be arranged, the cost is reduced, and the thickness of the display device is reduced.
Drawings
FIG. 1 shows a schematic diagram of the principle of ultrasonic wave generation;
FIG. 2 is a schematic diagram showing the principle of ultrasonic wave reception;
FIG. 3 shows a schematic view of an ultrasonic structure;
FIG. 4 shows a second ultrasonic structure;
FIG. 5 is a schematic diagram of a display module according to an embodiment of the invention;
FIG. 6 is a schematic diagram of a second display module according to an embodiment of the invention;
FIG. 7 is a schematic diagram showing the structures of the transmitting electrode layer and the receiving electrode layer according to an embodiment of the present invention;
FIG. 8 is a schematic diagram showing a second structure of the transmitting electrode layer and the receiving electrode layer according to an embodiment of the present invention;
FIG. 9 is a schematic diagram showing a state where the ultrasonic wave is in a plane wave form for touch control in the embodiment of the present invention;
FIG. 10 is a schematic diagram showing a state where the ultrasonic wave is focused to achieve touch control according to an embodiment of the present invention;
FIG. 11 is a schematic diagram showing a state that ultrasonic waves realize fingerprint recognition in a plane wave mode in the embodiment of the invention;
FIG. 12 is a schematic diagram showing a state in which the ultrasonic wave realizes fingerprint recognition in a focused waveform in the embodiment of the present invention;
fig. 13 is a schematic diagram of an ultrasonic circuit according to an embodiment of the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. It will be apparent that the described embodiments are some, but not all, embodiments of the invention. All other embodiments, which are obtained by a person skilled in the art based on the described embodiments of the invention, fall within the scope of protection of the invention.
In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
Fig. 1 shows a schematic view of an ultrasonic wave generating principle, where the ultrasonic wave generating structure includes a first piezoelectric material layer 1, and a first electrode 2 and a second electrode 3 located on opposite sides of the first piezoelectric material layer 1, and AC voltages (such as one end GND and the other end AC square waves) are input to the first electrode 2 and the second electrode 3, where the first piezoelectric material layer 1 deforms (or the piezoelectric material layer drives substrates of film layers located on opposite two layers of the piezoelectric material layer to vibrate together), so as to generate acoustic waves and transmit the acoustic waves; if an air cavity exists below the ultrasonic wave generating structure, the ultrasonic wave can be more convenient to strengthen and better transmitted.
Fig. 2 shows a schematic view of the principle of ultrasonic wave reception, where the ultrasonic wave reception structure includes a second piezoelectric material layer 4, and a third electrode 5 and a fourth electrode 6 located on opposite sides of the second piezoelectric material layer 4, and when an acoustic wave (reflected by an interface where different media intersect or reflected by a finger fingerprint) is reflected to the second piezoelectric material layer 4, the acoustic wave is converted into an AC voltage, and the fourth electrode 6 is connected to an output signal (for example, the third electrode 5 is grounded, and the fourth electrode 6 is a receiving end). The fingerprint can be identified according to different reflected energy and different signals of the valley and the ridge of the finger fingerprint.
Fig. 3 and fig. 4 each show a schematic view of an integrated arrangement of an ultrasonic wave generating structure and an ultrasonic wave receiving structure, including a transmitting electrode layer 10 and a receiving electrode layer 30 on the same side of a third piezoelectric material layer 40, in the structure of fig. 3, the transmitting electrode layer 10 is disposed on one side of a TFT substrate 20, the third piezoelectric material layer 40 is disposed on the other side of the TFT, the receiving electrode layer 30 and a plate electrode 50 are disposed on two opposite layers of the third piezoelectric material layer 40, the plate electrode 50 is grounded, the transmitting electrode layer 10 transmits signals and is reflected by finger fingerprints, the energy reflected by valleys and ridges is different, the energy reflected by valleys is strong, and thus the valley ridges of the finger fingerprints react through different signals. The receiving electrode layer 30 and the transmitting electrode layer 10 may also be located on the same side of the TFT substrate 20, referring to fig. 4.
From the above, the fingerprint identification can be performed by using the ultrasonic structure, in the related art, the fingerprint identification is generally realized by using the ultrasonic structure, and the capacitive touch device is used for touch detection, the capacitive touch device is arranged on the light emitting side of the display module, and the ultrasonic fingerprint identification device is arranged on the backlight side of the display module, however, the overall thickness of the display device is increased intangibly due to such arrangement, and the cost is increased.
To solve the above-mentioned technical problem, this embodiment provides a display module, referring to fig. 5 and 6, including a display panel, further including:
the ultrasonic sensor is arranged on the non-display side of the display panel and is used for transmitting ultrasonic waves, receiving reflected ultrasonic waves and converting the reflected ultrasonic waves into electric signals;
the touch detection module is arranged on the non-display side of the display panel, connected with the ultrasonic sensor and used for obtaining a finger touch position according to the electric signal in a touch detection mode so as to perform touch detection;
and the fingerprint identification module is arranged on the non-display side of the display panel, is connected with the ultrasonic sensor and is used for carrying out fingerprint identification according to the electric signal in a fingerprint identification mode.
In this embodiment, not only fingerprint identification is realized by utilizing the ultrasonic wave principle, but also touch detection is realized by utilizing the ultrasonic wave principle, and the two are integrated, so that the related structural arrangement of a capacitive touch device can be omitted, the thickness of the display device is reduced, the cost is reduced, and the capacitive touch device is removed, so that the overall display transmittance of the OLED display device is greatly increased, and the overall stress of the flexible display module is reduced.
In the case of acoustic reflection (acoustic reflexion), when an acoustic wave is incident on one medium, the acoustic wave is reflected at the interface between the two mediums, and a part of the energy of the incident acoustic wave is returned to the first medium. In this embodiment, touch detection is implemented by using the characteristic of the acoustic wave, where there is a region pressed or touched by a finger, the energy of the reflected acoustic wave becomes small (where there is a finger press or touch, the acoustic wave is reflected by the finger fingerprint, only a small portion of the energy is reflected back), and where there is no finger press or touch, the energy of the reflected acoustic wave becomes large (where there is no finger press or touch, the acoustic wave is reflected at the interface of the display panel and the air layer, and most of the acoustic wave is reflected by air), so that the finger touch position can be determined.
In this embodiment, the display panel 1 is an OLED display panel, the ultrasonic sensor is located on a backlight side of the OLED display panel, and a light emitting side of the OLED display panel is connected with a cover plate 5 through optical cement.
In this embodiment, the ultrasonic sensor includes a piezoelectric film layer 2, and a transmitting electrode layer 4 and a receiving electrode layer 3 located on opposite sides of the piezoelectric film layer 2;
in the ultrasonic wave transmitting stage, the transmitting electrode layer 4 receives an electric signal (the electric signal is a high-frequency signal), and the piezoelectric film layer 2 generates ultrasonic waves; in the ultrasonic wave receiving stage, after the ultrasonic wave propagates to the light emitting surface of the display panel 1 and is reflected, the ultrasonic wave is converted into an electric signal by the piezoelectric film layer 2, and the receiving electrode layer 3 receives the electric signal and transmits the electric signal to the fingerprint identification module or the touch detection module.
The piezoelectric film layer 2 is made of a piezoelectric material, for example, PVDF (polyvinylidene fluoride) film type piezoelectric material, but not limited thereto, and may be another inorganic or organic piezoelectric material such as AlN (aluminum nitride)/PZT (lead zirconate titanate piezoelectric ceramic)/ZnO (zinc oxide).
In this embodiment, the emitter electrode layer 4 includes a plurality of rows of stripe-shaped emitter electrodes 41 arranged along the first direction, the receiver electrode layer 3 includes a plurality of block-shaped receiver electrodes 31 arranged in an array, the orthographic projection of the receiver electrodes 31 on the emitter electrode layer 4 is located on the stripe-shaped emitter electrodes 41, and the orthographic projection of each receiver electrode 31 on the display panel 1 covers at least one pixel area, referring to fig. 7 and 8.
In this embodiment, the receiving electrode layer 3 further includes a thin film transistor connected to the receiving electrode 31, the touch detection module is connected to the thin film transistor through a reading signal line for performing touch detection, and the fingerprint identification module is connected to the thin film transistor through a reading signal line for performing fingerprint identification.
Referring to fig. 7, the entire screen area is divided into a plurality of rows of stripe-shaped emitter electrodes Tx (for example, one Tx line according to 3 to 5mm (referring to a width in a direction perpendicular to an extending direction of the stripe-shaped emitter electrodes), and a space between adjacent two rows of stripe-shaped emitter electrodes is as small as possible to satisfy a process such as a 5um interval distance).
The receiving electrodes 31 are in a block structure arranged in an array, and are divided according to 3-5 mm, and the intervals are um levels. The orthographic projection of the receiving electrode Rx on the transmitting electrode layer 4 is located on the stripe-shaped transmitting electrode Tx.
The sizes of the strip-shaped emitter electrode 41 and the receiver electrode 31 are not limited, and may be smaller, for example, 1 to 2mm or several hundred um.
The schematic circuit diagram of the ultrasonic sensor is shown in fig. 13, and the ultrasonic circuit includes a transmitting electrode Tx, a piezoelectric film layer 2PVDF, a receiving electrode Rx, a thin film transistor RST, a thin film transistor SF, and a thin film transistor SEL.
The receiving electrode Rx is connected with the source electrode of the thin film transistor RST and is connected with the gate electrode of the thin film transistor SF, the node voltage of the receiving electrode Rx is marked as Vin, the gate electrode and the drain electrode of the thin film transistor RST are electrically connected with an external control circuit, the external control circuit provides high level or low level for the gate electrode of the thin film transistor RST so as to control the on-off of the source electrode and the drain electrode of the thin film transistor RST, and the level provided by the external control circuit for the drain electrode of the thin film transistor RST is marked as Dbias. When the gate voltage difference to the thin film transistor RST is large enough, the source electrode and the drain electrode of the thin film transistor RST are completely conducted, namely, the source electrode and the drain electrode of the thin film transistor RST are conducted in two directions.
The drain electrode of the thin film transistor SEL is connected with the read signal line, the gate electrode of the thin film transistor SEL is connected with an external control circuit, and the external control circuit provides high level or low level for the gate electrode of the thin film transistor SEL so as to control the on-off of the source electrode and the drain electrode of the thin film transistor SEL.
The source of the thin film transistor SEL is connected to the drain of the thin film transistor SF, the drain of the thin film transistor SF is connected to an external control circuit, and the drain of the thin film transistor SF may be always at a fixed potential labeled Ap (e.g., 0V).
Ultrasonic wave generation stage: the drain electrode of the thin film transistor RST is applied with a stable voltage, the positioning Dbias is fixed (for example, 0v voltage), the transmitting electrode Tx is applied with a pulse voltage (0-100 v is different), and the piezoelectric film layer 2 is excited to generate ultrasonic waves;
ultrasonic wave receiving stage: the ultrasonic wave is reflected, the transmitting electrode Tx applies a stable voltage to a fixed potential (e.g., 0 v), the receiving electrode Rx receives the reflected signal, at this time, the thin film transistor RST is in an off state (preventing the current from sliding away), different signals received by the receiving electrode Rx are transmitted to the thin film transistor SF, the resistance is different, the current is different to reflect the valley or the ridge of the fingerprint (or whether there is finger touch), and the thin film transistor SEL is turned on to read the obtained signal.
It is understood that the thin film transistors RST, SF, SEL may be N-type thin film transistors, or P-type thin film transistors, where the source and drain of the P-type thin film transistors are connected in opposite manner to the source and drain of the N-type thin film transistors. The source electrode or the drain electrode of the thin film transistor is used as two electric connection stages, one of the source electrode or the drain electrode of the thin film transistor is a first end of the thin film transistor, and the other is a second end of the thin film transistor.
In this embodiment, a metal electrode layer 7 made of metal Ag is disposed on a side of the emitter electrode layer 4 away from the piezoelectric film layer 2, an insulating layer is disposed between the metal electrode layer 7 and the emitter electrode layer 4, and an insulating protection layer 8 is disposed on a side of the metal electrode layer 7 away from the piezoelectric film layer 2, referring to fig. 5.
Referring to fig. 5, the ultrasonic sensor includes a glass substrate, and a receiving electrode layer 3, a piezoelectric film layer 2 and a transmitting electrode layer 4 sequentially disposed on the glass substrate, one side of the transmitting electrode layer 4 away from the piezoelectric film layer 2 is provided with a metal electrode layer 7 and an insulating protective layer 8, an insulating layer (a first insulating layer 6) is disposed between the metal electrode layer 7 and the transmitting electrode layer 4, the transmitting electrode includes a plurality of rows of transmitting electrodes disposed along a first direction, the receiving electrode layer 3 includes a plurality of block-shaped receiving electrodes 31 arranged in an array, and orthographic projections of the plurality of receiving electrodes 31 on the transmitting electrode layer 4 are located on the corresponding transmitting electrodes, each receiving electrode 31 is connected with a thin film transistor to collect signals received by the receiving electrode 31, and then transmitted to the touch detection module or the fingerprint recognition module through a reading signal line connected with the thin film transistor.
The transmitting electrode layer 4 and the receiving electrode layer 3 shown in fig. 5 are each schematically configured, and are merely for showing the relative positional relationship among the structures such as the transmitting electrode layer 4, the piezoelectric film layer 2, and the receiving electrode layer 3, and are not limited to specific structural configurations.
In the acoustic wave field, the larger the acoustic resistance difference of two media is, the larger the mass difference of the media is, and the larger the sound velocity change is. The larger the difference in acoustic impedance, the larger the inertia of phonons, and the larger the inertia creates an energy condition for ultrasonic reflection, so that the larger the difference in acoustic impedance of two media, the larger the ultrasonic reflection capability. Wherein, acoustic impedance is: acoustic impedance = density x sound velocity in the medium, obviously, acoustic impedance is proportional to density, therefore is provided with high density metal layer in the transmitting electrode layer 4 side that deviates from piezoelectric film layer 2 for the ultrasonic wave that vibration in the piezoelectric film layer 2 produced can be mostly reflected to the direction towards the flat layer through high density metal layer, has improved fingerprint identification or touch-control's precision.
In the embodiment, the metal electrode layer 7 is made of Ag, but not limited thereto.
In this embodiment, an insulating layer is disposed on a side of the emitter electrode layer 4 away from the piezoelectric film layer 2, and an absolute value of a difference between a density of an insulating material used for the insulating layer and a density of the metal Ag is smaller than a preset value, referring to fig. 6.
The preset value can be set according to actual needs, the insulating layer made of insulating material with the density close to that of the metal Ag is adopted to replace the metal electrode layer 7 made of the metal Ag, the insulating layer between the metal electrode layer 7 and the emission electrode layer 4 can be omitted, and the process structure is simplified.
The insulating material can be metal or nonmetal doped and synthesized, but is guaranteed to be non-conductive, but the density of the insulating material is close to that of metal Ag so as to guarantee the reflecting capability of ultrasonic waves.
Referring to fig. 6, the ultrasonic sensor includes a glass substrate, and the receiving electrode layer 3, the piezoelectric film layer 2 and the transmitting electrode layer 4 sequentially disposed on the glass substrate, an insulating layer (second insulating layer 60) is disposed on a side of the transmitting electrode layer 4 away from the piezoelectric film layer 2, an insulating protection layer 8 is disposed on a side of the insulating layer away from the transmitting electrode layer 4 to prevent water oxygen erosion, the transmitting electrode includes a plurality of rows of transmitting electrodes disposed along a first direction, the receiving electrode layer 3 includes a plurality of block-shaped receiving electrodes 31 arranged in an array, and orthographic projections of the plurality of receiving electrodes 31 on the transmitting electrode layer 4 are disposed on the corresponding transmitting electrodes, each of the receiving electrodes 31 is connected with a thin film transistor to collect signals received by the receiving electrode 31, and then transmitted to the touch detection module or the fingerprint recognition module through a reading signal line connected with the thin film transistor.
The emitter electrode layer 4 and the receiver electrode layer 3 shown in fig. 6 are schematic structures, and are merely for showing the relative positional relationship among the structures of the emitter electrode layer 4, the piezoelectric film layer 2, and the receiver electrode layer 3, and are not limited to specific structural arrangements.
The embodiment of the invention also provides an ultrasonic touch detection method which is applied to the display module and comprises the following steps:
controlling an ultrasonic sensor to send ultrasonic waves;
controlling an ultrasonic sensor to receive the reflected ultrasonic wave and converting the ultrasonic wave into an electric signal;
and obtaining the touch position of the finger according to the electric signal so as to perform touch detection.
Specifically, the ultrasonic touch detection method applied to the display module comprises the following steps:
applying a high-frequency signal to a first row of strip-shaped emission electrodes 41 among the plurality of rows of strip-shaped emission electrodes 41, wherein the voltage of the strip-shaped emission electrodes 41 outside the first row of strip-shaped emission electrodes 41 is zero, so that the piezoelectric film layer 2 generates ultrasonic waves;
the piezoelectric film layer 2 receives the reflected ultrasonic wave and converts it into an electric signal;
a plurality of receiving electrodes 31 positioned above the first row of strip-shaped transmitting electrodes 41 are orthographically projected on the transmitting electrode layer 4, receive the electric signals, and are read by corresponding reading signal lines after being processed by corresponding thin film transistors;
And finishing touch scanning line by line according to the steps, and judging the touch position of the finger according to the fact that the energy of a signal reflected back by the area with the finger touch is smaller than that of a signal reflected back by the area without the finger touch.
Referring to fig. 7 and 9, the touch detection is performed by using a plane wave mode, and may also be performed by using a focused wave mode, which is specifically as follows.
Referring to fig. 7, the strip-shaped transmitting electrode Tx1 is first supplied with a voltage (10 to 200V), a high frequency signal (1 to 20 MHz), and then, after striking the finger surface, the sound wave is reflected; the other rows of strip-shaped transmitting electrodes Tx are all at a fixed potential, such as 0V;
the receiving electrodes Rx11, rx12, rx13 … Rx1n corresponding to the stripe-shaped transmitting electrode Tx1 store all signals and read; all other non-read receiving electrodes Rx are continuously supplied with a fixed potential, such as 0V;
then, according to the above steps, the strip-shaped transmitting electrode Tx2 is applied with a voltage, a high-frequency signal (all other strip-shaped transmitting electrodes Tx are at a fixed potential), then the finger is applied to the touch surface, after the sound wave is reflected back, the corresponding receiving electrode Rx21 … Rx2n receives and reads the sound wave, and the other receiving electrodes Rx are also applied with a fixed potential.
And finishing the steps line by line.
Referring to fig. 8 and 10, in this embodiment, the method for detecting ultrasonic touch control is applied to the display module set described above, and includes the following steps:
Dividing the plurality of rows of the strip-shaped emission electrodes 41 into a plurality of electrode groups, each electrode group including an odd number of the strip-shaped emission electrodes 41, and the number of the strip-shaped emission electrodes 41 included in each electrode group being greater than or equal to 3;
the method comprises the steps of carrying out phase focusing on a plurality of strip-shaped emitting electrodes 41 in a first electrode group in a plurality of electrode groups by utilizing a focusing wave forming principle, so that ultrasonic waves generated by applying high-frequency signals to the plurality of strip-shaped emitting electrodes 41 in the first electrode group are converged and overlapped in a first area of a light-emitting surface of a display panel 1, wherein the first area is an area covered by orthographic projection of the focusing electrode on the display panel 1, and the focusing electrode is the strip-shaped emitting electrode 41 positioned in the central position in the first electrode group;
a plurality of receiving electrodes 31 positioned on the focusing electrode are orthographically projected on the transmitting electrode layer 4, receive the electric signals, and are read by corresponding reading signal lines after being processed by corresponding thin film transistors;
and carrying out phase focusing on other electrode groups except the first electrode group in sequence according to the steps to finish touch scanning, and judging the touch position of the finger according to the fact that the energy of a signal reflected back by the area with the finger touch is smaller than that of a signal reflected back by the area without the finger touch.
The method comprises the steps of carrying out phase focusing by adopting a plurality of rows of strip-shaped transmitting electrodes Tx in a plurality of electrode groups, carrying out receiving and reading on all pixels of the corresponding row after focusing on a certain row of strip-shaped transmitting electrodes Tx, then carrying out focusing on electrode groups by electrode groups, and receiving electrode groups by electrode groups. The focusing is performed sequentially, and the focusing has the advantages that if the same voltage is applied, the focused energy can be larger, the identification of true and false skins (human skin is divided into dermis and false skins, the distance between the true and false skins can be obtained through the reflected energy difference, which is generally 150um, and whether the skin structure of a real person can be identified by utilizing ultrasonic waves when the ultrasonic wave reflection capability is large enough) or the identification of blood vessels (blood vessels comprise blood-existing parts and blood-free parts, and the partially reflected energy of the blood-existing parts and the partially reflected energy of the blood-free parts are different, so that the identification can be performed according to the reflected energy difference).
The touch control is realized by focusing waves, if the signal quantity is large enough, the voltage of each strip-shaped transmitting electrode Tx can be reduced, so that smaller voltage driving can be realized, the requirement on an IC chip required by the strip-shaped transmitting electrode Tx is reduced, and mass production and cost reduction are facilitated.
In the present embodiment, the plurality of strip-shaped transmitting electrodes 41 in the first electrode group of the plurality of electrode groups are phase-focused by utilizing the formation principle of the focusing wave, so that the ultrasonic waves generated by applying the high-frequency signals to the plurality of strip-shaped transmitting electrodes 41 in the first electrode group are converged and overlapped in the first area of the light-emitting surface of the display panel 1; the method specifically comprises the following steps:
setting a strip-shaped transmitting electrode 41 positioned at the central position in the first electrode group as a focusing electrode, and applying high-frequency signals to the plurality of strip-shaped transmitting electrodes 41 according to a preset time sequence so that the generated ultrasonic waves are converged and overlapped in the first area;
the predetermined time sequence includes sequentially applying a high frequency signal from the strip-shaped emitter electrode 41 positioned at the edge position of the first electrode group to the strip-shaped emitter electrode 41 positioned at the center position of the first electrode group in the first direction, and simultaneously applying a high frequency signal to each pair of strip-shaped emitter electrodes 41 symmetrically disposed at both sides of the focusing electrode.
In fig. 8, a focused wave is illustrated by taking an example in which 3 rows of the stripe-shaped emitter electrodes 41 are included in one electrode group. The stripe-shaped transmitting electrode Tx1 and the stripe-shaped transmitting electrode Tx5 are farthest from the stripe-shaped transmitting electrode Tx3, and transmit signals first, and the stripe-shaped transmitting electrode Tx2 and the stripe-shaped transmitting electrode Tx4 transmit signals later, and the stripe-shaped transmitting electrode Tx3 transmits signals last. The ultrasonic plane wave is converged above the strip-shaped transmitting electrode Tx3, reflected by the finger, received by the receiving electrodes Rx31, rx32 … Rx3n corresponding to the strip-shaped transmitting electrode Tx3, and then read out.
The embodiment of the invention also provides an ultrasonic fingerprint identification method which is applied to the display module and comprises the following steps:
controlling an ultrasonic sensor to send ultrasonic waves;
controlling an ultrasonic sensor to receive the reflected ultrasonic wave and converting the ultrasonic wave into an electric signal;
and fingerprint identification is carried out according to the electric signals.
In this embodiment, the method for identifying the ultrasonic fingerprint applied to the display module set described above, referring to fig. 7 and 11, includes the following steps:
applying a high-frequency signal to a first row of strip-shaped emission electrodes 41 among the plurality of rows of strip-shaped emission electrodes 41, wherein the voltage of the strip-shaped emission electrodes 41 outside the first row of strip-shaped emission electrodes 41 is zero, so that the piezoelectric film layer 2 generates ultrasonic waves;
the piezoelectric film layer 2 receives the reflected ultrasonic wave and converts it into an electric signal;
a plurality of receiving electrodes 31 positioned above the first row of strip-shaped transmitting electrodes 41 are orthographically projected on the transmitting electrode layer 4, receive the electric signals, and are read by corresponding reading signal lines after being processed by corresponding thin film transistors;
scanning is completed line by line according to the steps, and fingerprint information is identified according to the difference of energy of signals reflected by the ridges of the finger.
Referring to fig. 7, the strip-shaped transmitting electrode Tx1 is first supplied with a voltage (10 to 200V), a high frequency signal (1 to 20 MHz), and then, after striking the finger surface, the sound wave is reflected; the other rows of strip-shaped transmitting electrodes Tx are all at a fixed potential, such as 0V;
The receiving electrodes Rx11, rx12, rx13 … Rx1n corresponding to the stripe-shaped transmitting electrode Tx1 store all signals and read; all other non-read receiving electrodes Rx are continuously supplied with a fixed potential, such as 0V;
then, according to the above steps, the strip-shaped transmitting electrode Tx2 is applied with a voltage, a high-frequency signal (all other strip-shaped transmitting electrodes Tx are at a fixed potential), then the finger is applied to the touch surface, after the sound wave is reflected back, the corresponding receiving electrode Rx21 … Rx2n receives and reads the sound wave, and the other receiving electrodes Rx are also applied with a fixed potential.
And finishing the steps line by line.
In this embodiment, the ultrasonic fingerprint identification method applied to the display module set described above, referring to fig. 8 and 12, includes the following steps:
dividing the plurality of rows of the strip-shaped emission electrodes 41 into a plurality of electrode groups, each electrode group including an odd number of the strip-shaped emission electrodes 41, and the number of the strip-shaped emission electrodes 41 included in each electrode group being greater than or equal to 3;
the method comprises the steps of carrying out phase focusing on a plurality of strip-shaped emitting electrodes 41 in a first electrode group in a plurality of electrode groups by utilizing a focusing wave forming principle, so that ultrasonic waves generated by applying high-frequency signals to the plurality of strip-shaped emitting electrodes 41 in the first electrode group are converged and overlapped in a first area of a light-emitting surface of a display panel 1, wherein the first area is an area covered by orthographic projection of the focusing electrode on the display panel 1, and the focusing electrode is the strip-shaped emitting electrode 41 positioned in the central position in the first electrode group;
A plurality of receiving electrodes 31 positioned on the focusing electrode are orthographically projected on the transmitting electrode layer 4, receive the electric signals, and are read by corresponding reading signal lines after being processed by corresponding thin film transistors;
and carrying out phase focusing on other electrode groups except the first electrode group in sequence according to the steps to finish scanning, and identifying fingerprint information according to different energy of signals reflected by the ridges of the finger.
In the present embodiment, the plurality of strip-shaped transmitting electrodes 41 in the first electrode group of the plurality of electrode groups are phase-focused by utilizing the formation principle of the focusing wave, so that the ultrasonic waves generated by applying the high-frequency signals to the plurality of strip-shaped transmitting electrodes 41 in the first electrode group are converged and overlapped in the first area of the light-emitting surface of the display panel 1; the method specifically comprises the following steps:
setting a strip-shaped transmitting electrode 41 positioned at the central position in the first electrode group as a focusing electrode, and applying high-frequency signals to the plurality of strip-shaped transmitting electrodes 41 according to a preset time sequence so that the generated ultrasonic waves are converged and overlapped in the first area;
the predetermined time sequence includes sequentially applying a high frequency signal from the strip-shaped emitter electrode 41 positioned at the edge position of the first electrode group to the strip-shaped emitter electrode 41 positioned at the center position of the first electrode group in the first direction, and simultaneously applying a high frequency signal to each pair of strip-shaped emitter electrodes 41 symmetrically disposed at both sides of the focusing electrode.
In fig. 8, a focused wave is illustrated by taking an example in which 3 rows of the stripe-shaped emitter electrodes 41 are included in one electrode group. The stripe-shaped transmitting electrode Tx1 and the stripe-shaped transmitting electrode Tx5 are farthest from the stripe-shaped transmitting electrode Tx3, and transmit signals first, and the stripe-shaped transmitting electrode Tx2 and the stripe-shaped transmitting electrode Tx4 transmit signals later, and the stripe-shaped transmitting electrode Tx3 transmits signals last. The ultrasonic plane wave is converged above the strip-shaped transmitting electrode Tx3, reflected by the finger, received by the receiving electrodes Rx31, rx32 … Rx3n corresponding to the strip-shaped transmitting electrode Tx3, and then read out.
While the invention has been described with respect to the preferred embodiments, it will be understood by those skilled in the art that various modifications and changes can be made without departing from the principles of the invention, and such modifications and changes are also intended to be included within the scope of the invention.
Claims (2)
1. The ultrasonic touch detection method is characterized by being applied to a display module, and comprises a display panel and further comprises the following steps:
the ultrasonic sensor is arranged on the non-display side of the display panel and is used for transmitting ultrasonic waves, receiving reflected ultrasonic waves and converting the reflected ultrasonic waves into electric signals;
the touch detection module is arranged on the non-display side of the display panel, connected with the ultrasonic sensor and used for obtaining a finger touch position according to the electric signal in a touch detection mode so as to perform touch detection;
The fingerprint identification module is arranged on the non-display side of the display panel, is connected with the ultrasonic sensor and is used for carrying out fingerprint identification according to the electric signal in a fingerprint identification mode;
the ultrasonic sensor comprises a piezoelectric film layer, and a transmitting electrode layer and a receiving electrode layer which are positioned on two opposite sides of the piezoelectric film layer;
in the ultrasonic wave transmitting stage, the transmitting electrode layer receives an electric signal, and the piezoelectric film layer generates ultrasonic waves; in the ultrasonic wave receiving stage, ultrasonic waves are transmitted to the light emitting surface of the display panel and are reflected and then are converted into electric signals by the piezoelectric film layer, and the electric signals are received by the receiving electrode layer and transmitted to the fingerprint identification module or the touch detection module;
the emitting electrode layer comprises a plurality of rows of strip-shaped emitting electrodes arranged along a first direction, the receiving electrode layer comprises a plurality of block-shaped receiving electrodes arranged in an array manner, orthographic projections of the receiving electrodes on the emitting electrode layer are positioned on the strip-shaped emitting electrodes, and orthographic projections of each receiving electrode on the display panel cover at least one pixel area;
the receiving electrode layer also comprises a thin film transistor connected with the receiving electrode, the touch detection module is connected with the thin film transistor through a reading signal line for touch detection, and the fingerprint identification module is connected with the thin film transistor through a reading signal line for fingerprint identification;
A metal electrode layer made of metal Ag is arranged on one side, far away from the piezoelectric film layer, of the emission electrode layer, an insulating layer is arranged between the metal electrode layer and the emission electrode layer, and an insulating protection layer is arranged on one side, far away from the piezoelectric film layer, of the metal electrode layer;
an insulating layer is arranged on one side, far away from the piezoelectric film layer, of the emitting electrode layer, and the absolute value of the difference value between the density of an insulating material adopted by the insulating layer and the density of the metal Ag is smaller than a preset value.
The ultrasonic touch detection method comprises the following steps:
controlling an ultrasonic sensor to send ultrasonic waves;
controlling an ultrasonic sensor to receive the reflected ultrasonic wave and converting the ultrasonic wave into an electric signal;
acquiring a finger touch position according to the electric signal so as to perform touch detection;
the method also comprises the following steps:
dividing a plurality of rows of strip-shaped emission electrodes into a plurality of electrode groups, wherein each electrode group comprises an odd number of strip-shaped emission electrodes, and the number of the strip-shaped emission electrodes included in each electrode group is more than or equal to 3;
carrying out phase focusing on a plurality of strip-shaped transmitting electrodes in a first electrode group in a plurality of electrode groups by utilizing a focusing wave forming principle, so that ultrasonic waves generated by applying high-frequency signals to the plurality of strip-shaped transmitting electrodes in the first electrode group are converged and overlapped in a first area of a light-emitting surface of a display panel, wherein the first area is an area covered by orthographic projection of a focusing electrode on the display panel, and the focusing electrode is a strip-shaped transmitting electrode positioned at the central position in the first electrode group;
A plurality of receiving electrodes positioned on the focusing electrode are orthographically projected on the transmitting electrode layer, and the receiving electrodes receive the electric signals and are read by corresponding reading signal lines after being processed by corresponding thin film transistors;
according to the steps, the other electrode groups except the first electrode group are sequentially subjected to phase focusing to finish touch scanning, and the finger touch position is judged according to the fact that the energy of a signal reflected back by a region with finger touch is smaller than that of a signal reflected back by a region without finger touch;
carrying out phase focusing on a plurality of strip-shaped transmitting electrodes in a first electrode group in a plurality of electrode groups by utilizing a focusing wave forming principle, so that ultrasonic waves generated by applying high-frequency signals to the plurality of strip-shaped transmitting electrodes in the first electrode group are converged and overlapped in a first area of a light-emitting surface of a display panel; the method specifically comprises the following steps:
setting a strip-shaped transmitting electrode positioned at the central position in a first electrode group as a focusing electrode, and applying high-frequency signals to a plurality of strip-shaped transmitting electrodes according to a preset time sequence so that generated ultrasonic waves are converged and overlapped in the first area;
the preset time sequence comprises the steps of sequentially applying high-frequency signals along a first direction from the strip-shaped emitting electrodes positioned at the edge positions of the first electrode group to the strip-shaped emitting electrodes positioned at the center positions of the first electrode group, and simultaneously applying the high-frequency signals to each pair of strip-shaped emitting electrodes symmetrically arranged at the two sides of the focusing electrode.
2. The ultrasonic fingerprint identification method is characterized by being applied to a display module, comprising a display panel and further comprising the following steps:
the ultrasonic sensor is arranged on the non-display side of the display panel and is used for transmitting ultrasonic waves, receiving reflected ultrasonic waves and converting the reflected ultrasonic waves into electric signals;
the touch detection module is arranged on the non-display side of the display panel, connected with the ultrasonic sensor and used for obtaining a finger touch position according to the electric signal in a touch detection mode so as to perform touch detection;
the fingerprint identification module is arranged on the non-display side of the display panel, is connected with the ultrasonic sensor and is used for carrying out fingerprint identification according to the electric signal in a fingerprint identification mode;
the ultrasonic sensor comprises a piezoelectric film layer, and a transmitting electrode layer and a receiving electrode layer which are positioned on two opposite sides of the piezoelectric film layer;
in the ultrasonic wave transmitting stage, the transmitting electrode layer receives an electric signal, and the piezoelectric film layer generates ultrasonic waves; in the ultrasonic wave receiving stage, ultrasonic waves are transmitted to the light emitting surface of the display panel and are reflected and then are converted into electric signals by the piezoelectric film layer, and the electric signals are received by the receiving electrode layer and transmitted to the fingerprint identification module or the touch detection module;
The emitting electrode layer comprises a plurality of rows of strip-shaped emitting electrodes arranged along a first direction, the receiving electrode layer comprises a plurality of block-shaped receiving electrodes arranged in an array manner, orthographic projections of the receiving electrodes on the emitting electrode layer are positioned on the strip-shaped emitting electrodes, and orthographic projections of each receiving electrode on the display panel cover at least one pixel area;
the receiving electrode layer also comprises a thin film transistor connected with the receiving electrode, the touch detection module is connected with the thin film transistor through a reading signal line for touch detection, and the fingerprint identification module is connected with the thin film transistor through a reading signal line for fingerprint identification;
a metal electrode layer made of metal Ag is arranged on one side, far away from the piezoelectric film layer, of the emission electrode layer, an insulating layer is arranged between the metal electrode layer and the emission electrode layer, and an insulating protection layer is arranged on one side, far away from the piezoelectric film layer, of the metal electrode layer;
an insulating layer is arranged on one side, far away from the piezoelectric film layer, of the emitting electrode layer, and the absolute value of the difference value between the density of an insulating material adopted by the insulating layer and the density of the metal Ag is smaller than a preset value.
The ultrasonic fingerprint identification method comprises the following steps:
controlling an ultrasonic sensor to send ultrasonic waves;
controlling an ultrasonic sensor to receive the reflected ultrasonic wave and converting the ultrasonic wave into an electric signal;
fingerprint identification is carried out according to the electric signals;
the method also comprises the following steps:
dividing a plurality of rows of strip-shaped emission electrodes into a plurality of electrode groups, wherein each electrode group comprises an odd number of strip-shaped emission electrodes, and the number of the strip-shaped emission electrodes included in each electrode group is more than or equal to 3;
carrying out phase focusing on a plurality of strip-shaped transmitting electrodes in a first electrode group in a plurality of electrode groups by utilizing a focusing wave forming principle, so that ultrasonic waves generated by applying high-frequency signals to the plurality of strip-shaped transmitting electrodes in the first electrode group are converged and overlapped in a first area of a light-emitting surface of a display panel, wherein the first area is an area covered by orthographic projection of a focusing electrode on the display panel, and the focusing electrode is a strip-shaped transmitting electrode positioned at the central position in the first electrode group;
a plurality of receiving electrodes positioned on the focusing electrode are orthographically projected on the transmitting electrode layer, and the receiving electrodes receive the electric signals and are read by corresponding reading signal lines after being processed by corresponding thin film transistors;
According to the steps, the other electrode groups except the first electrode group are sequentially subjected to phase focusing to finish scanning, and fingerprint information is identified according to different energy of signals reflected by the ridges of the finger;
carrying out phase focusing on a plurality of strip-shaped transmitting electrodes in a first electrode group in a plurality of electrode groups by utilizing a focusing wave forming principle, so that ultrasonic waves generated by applying high-frequency signals to the plurality of strip-shaped transmitting electrodes in the first electrode group are converged and overlapped in a first area of a light-emitting surface of a display panel; the method specifically comprises the following steps:
setting a strip-shaped transmitting electrode positioned at the central position in a first electrode group as a focusing electrode, and applying high-frequency signals to a plurality of strip-shaped transmitting electrodes according to a preset time sequence so that generated ultrasonic waves are converged and overlapped in the first area;
the preset time sequence comprises the steps of sequentially applying high-frequency signals along a first direction from the strip-shaped emitting electrodes positioned at the edge positions of the first electrode group to the strip-shaped emitting electrodes positioned at the center positions of the first electrode group, and simultaneously applying the high-frequency signals to each pair of strip-shaped emitting electrodes symmetrically arranged at the two sides of the focusing electrode.
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| CN112597845B (en) * | 2020-12-14 | 2024-03-19 | 京东方科技集团股份有限公司 | Fingerprint identification device, fingerprint identification method and display device |
| CN113065440A (en) * | 2021-03-25 | 2021-07-02 | 惠州市华星光电技术有限公司 | Display panel and display device |
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