CN104881193B - Touch control display apparatus, pressure touch unit and preparation method thereof - Google Patents

Abstract

The invention relates to a pressure touch unit, a touch display device using the pressure touch unit, and a manufacturing method of the pressure touch unit. The flexible circuit board includes a first base layer, a first circuit layer, a first encapsulation layer, a second circuit layer, an adhesive layer, a third circuit layer, a second encapsulation layer, a fourth circuit layer and a second base layer arranged in sequence , the adhesive layer is provided with a hole to expose part of the second circuit layer and the third circuit layer. The piezoelectric film sensor includes a piezoelectric film and an upper electrode and a lower electrode respectively located on both sides of the piezoelectric film, the piezoelectric film sensor is arranged at the hole of the flexible circuit board, and the upper electrode and the second The circuit layer is connected, and the lower electrode is connected to the third circuit layer. Integrating the piezoelectric film sensor on the flexible circuit board can simplify the wiring design of the piezoelectric film sensor and facilitate the assembly of the pressure touch control unit in the touch display device.

Description

Touch display device, pressure touch unit and manufacturing method thereof

technical field

The invention belongs to the field of touch display and relates to a touch display device, in particular to a touch display device with pressure sensing function, a pressure touch unit and a manufacturing method thereof.

Background technique

At present, more and more electronic products such as mobile phones, tablet computers, and televisions with touch functions adopt capacitive touch solutions. However, the capacitive touch screen also has many defects. For example, when a large area of the palm or conductor is close to the capacitive touch screen instead of touching, it will cause misjudgment of the capacitive touch screen; When there are water droplets or stains on the surface of the touch screen, it will also cause misoperation or insensitive operation of the capacitive touch screen; in addition, the capacitive touch screen cannot be operated normally with gloved hands or non-conductive objects.

Aiming at the problem of misoperation of the capacitive touch screen caused when the surface of the capacitive touch screen is wet or stained, no satisfactory solution has been found so far. Some manufacturers improve the touch operation effect when wearing gloves by improving the sensitivity of the capacitive touch screen, but this solution will make the capacitive touch screen too sensitive when operating without gloves and cause misoperation. This solution cannot solve the touch operation of non-conductive objects. There are also some manufacturers that combine touch solutions using pressure sensors, but there are defects such as difficult assembly and manufacturing and high cost.

Contents of the invention

Based on this, it is necessary to provide a pressure touch unit, a touch display device using the pressure touch unit, and a manufacturing method of the pressure touch unit in order to solve the above problems.

A pressure touch unit, including a flexible circuit board and a piezoelectric film sensor arranged on the flexible circuit board, wherein:

The flexible circuit board includes a first base layer, a first circuit layer, a first encapsulation layer, a second circuit layer, an adhesive layer, a third circuit layer, a second encapsulation layer, a fourth circuit layer and a second base layer arranged in sequence , holes are set on the adhesive layer and part of the second circuit layer and the third circuit layer are exposed;

The piezoelectric film sensor includes a piezoelectric film and an upper electrode and a lower electrode respectively located on both sides of the piezoelectric film, the piezoelectric film sensor is arranged at the hole of the flexible circuit board, and the upper electrode and the second The circuit layer is connected, and the lower electrode is connected to the third circuit layer.

The above-mentioned pressure touch unit integrates the piezoelectric film sensor on the flexible circuit board, which can simplify the wiring design of the pressure sensor and facilitate the assembly of the pressure touch unit in the touch display device.

In one embodiment, the upper electrode is connected to the second circuit layer through a conductive glue, and the lower electrode is connected to the third circuit layer through another conductive glue.

In one of the embodiments, the first encapsulation layer, the second encapsulation layer, and the adhesive layer are provided with corresponding channels, so that part of the lines on the first line layer, the fourth line layer and the second line layer are conducted, And it is used for grounding treatment, so that the first circuit layer and the fourth circuit layer are used as electromagnetic shielding layers.

In one of the embodiments, the interface end of the flexible circuit board also forms a reinforcement board on the outside of the second base layer.

A touch display device, comprising any one of the pressure touch units mentioned above.

A method for manufacturing a pressure touch unit, comprising the steps of:

Provide a piezoelectric film sensor, including a piezoelectric film, an upper electrode and a lower electrode respectively located on both sides of the piezoelectric film, and an upper release film and a lower release film respectively located outside the upper electrode and the lower electrode;

Provide a flexible circuit board, including a first base layer, a first circuit layer, a first encapsulation layer, a second circuit layer, an adhesive layer, a third circuit layer, a second encapsulation layer, a fourth circuit layer and a second base layer arranged in sequence , wherein a hole is set at the corresponding position of the adhesive layer and part of the second circuit layer and the third circuit layer are exposed, a conductive adhesive is provided at the hole to conduct with the second circuit layer, and another conductive adhesive is provided to conduct with the third circuit layer , a release film is set between the two conductive adhesives;

Remove the upper release film and the lower release film in the piezoelectric film sensor, and remove the release film in the flexible circuit board, so that the piezoelectric film sensor is arranged in the hole, and the upper electrode is bonded with the conductive adhesive, and the lower electrode is Bond with another conductive adhesive.

In one of the embodiments, the preparation steps of the piezoelectric film sensor include: providing a piezoelectric film; making upper electrodes and lower electrodes on both sides of the piezoelectric film; die-cutting the piezoelectric film with the upper and lower electrodes; And an upper release film is formed on the surface of the upper electrode, and a lower release film is formed on the surface of the lower electrode.

In one of the embodiments, the manufacturing steps of the flexible circuit board include: preparing a substrate, drilling holes on the substrate, and then preparing a second circuit layer containing electrode patterns; preparing a circuit layer containing electrode patterns on another substrate. The third circuit layer; laminate and protect the second circuit layer and the third circuit layer; use glue to bond the two substrates, wherein the electrode patterns of the second circuit layer and the third circuit layer are directly opposite and parallel Facingly placed; Drill the grounded through-holes on the two bonded substrates, and form the first line layer and the fourth line layer, and part of the lines of the first line layer, the fourth line layer and the second line layer are connected ; forming a first base layer and a second base layer on the surface of the first circuit layer and the fourth circuit layer; and punching, and pasting the upper and lower conductive adhesives with release films on the unbonded parts of the two substrates.

In one of the embodiments, the manufacturing step of the flexible circuit board further includes the step of forming a reinforcement board on the outer side of the second base layer.

Description of drawings

FIG. 1 is a schematic structural diagram of a touch display device provided by an embodiment of the present invention;

FIG. 2 is a schematic cross-sectional structure diagram of the touch display device shown in FIG. 1;

3 and 4 are schematic cross-sectional structural diagrams of touch display devices provided by different embodiments of the present invention;

FIG. 5 is a schematic structural diagram of a pressure touch unit provided by an embodiment of the present invention;

FIG. 6 is a schematic cross-sectional structure diagram of the pressure touch unit shown in FIG. 5;

FIG. 6A is similar to FIG. 6, showing a cross-sectional structure of a pressure touch unit provided by another embodiment;

Fig. 7 is a schematic structural diagram of a piezoelectric film sensor provided by an embodiment of the present invention;

FIG. 8 is a schematic structural diagram of a flexible circuit board for integrating piezoelectric film sensors provided by an embodiment of the present invention;

9 and 10 are a cross-sectional view and a front view of the interface end of the flexible circuit board shown in FIG. 8;

Fig. 11 is a flow chart of manufacturing a flexible circuit board for integrating piezoelectric film sensors provided by an embodiment of the present invention;

12 is a schematic cross-sectional structure diagram of a pressure touch unit provided by another embodiment of the present invention;

13 and 14 are a cross-sectional view and a front view of the flexible circuit board in the pressure touch unit shown in FIG. 12 at the interface end;

FIG. 15 is a schematic cross-sectional structure diagram of a touch display device applying the pressure touch unit provided in FIG. 12;

FIG. 16 is a schematic cross-sectional structure diagram of a pressure touch unit provided by another embodiment of the present invention;

17 and 18 are a cross-sectional view and a front view of the flexible circuit board in the pressure touch unit shown in FIG. 16 at the interface end;

FIG. 19 is a schematic cross-sectional structure diagram of a touch display device applying the pressure touch unit provided in FIG. 16;

20 is a schematic cross-sectional structure diagram of a pressure touch unit provided by another embodiment of the present invention;

21 and 22 are a cross-sectional view and a front view of the flexible circuit board in the pressure touch unit shown in FIG. 20 at the interface end;

FIG. 23 is a schematic cross-sectional structure diagram of a touch display device applying the pressure touch unit provided in FIG. 20;

FIG. 24 and FIG. 25 are structural schematic diagrams of different viewing angles of a touch display device provided by another embodiment of the present invention.

Detailed ways

As shown in FIGS. 1 and 2 , a touch display device provided by an embodiment of the present invention includes a protective cover 10 , a capacitive touch unit 20 , a pressure touch unit 30 and a display unit 40 . When the user operates the touch display device, the capacitive touch unit 20 can be used to determine the position information of the touch point, and at the same time, the pressure touch unit 30 can be used to determine the pressure information applied by the touch point, and then use the pressure information to realize specific function.

The protective cover 10 may be a tempered glass cover, a plastic cover, a polymethyl methacrylate (PMMA) cover or the like.

The capacitive touch unit 20 includes a capacitive sensor 21 , a flexible circuit board 22 connected to the capacitive sensor 21 , and a capacitive touch chip (not shown). The capacitive sensor 21 includes a plurality of driving electrodes and sensing electrodes. These two kinds of touch electrodes (not shown in the figure) can be distributed on the same substrate (not shown in the figure), or distributed on two different substrates respectively. The control electrode can be formed on the inner surface of the protective cover 10 so that the protective cover 10 also has the function of a capacitive sensor. It may also be formed on the surface of the insulating base material bonded to the protective cover 10 . The capacitive sensor 21 also includes a guide electrode (not shown in the figure, such as silver paste) that is electrically connected to the touch electrode. bound. The capacitive touch chip can be arranged on the flexible circuit board 22 of the capacitive touch unit 20, and can also be arranged on the main board of the touch display device. For example, when the touch display device is a mobile phone, the capacitive touch unit 20 can be The capacitive touch chip is integrated and arranged on the motherboard of the mobile phone.

The capacitive touch unit 20 can detect and obtain accurate position information of multiple touch points through capacitive coupling.

The pressure touch unit 30 includes a flexible circuit board 32 , three or more pressure sensors 31 disposed on the flexible circuit board 32 , and a control chip (not shown). The pressure sensor 31 may be a piezoelectric film sensor, a resistive force sensor, a capacitive force sensor, or a metal strain gauge.

In this embodiment, the pressure touch unit 30 is located on a side of the capacitive touch unit 20 away from the protective cover 10 . In other words, in this embodiment, the protective cover 10 , the capacitive touch unit 20 , the pressure touch unit 30 and the display unit 40 are arranged in sequence in the touch display device.

As shown in FIG. 3 , in some embodiments, the pressure touch unit 30 can also be located on the side of the display unit 40 away from the capacitive touch unit 20 , and the display unit 40 is located on the side of the capacitive touch unit 20 away from the protective cover 10 . side. In this embodiment, the protective cover 10 , the capacitive touch unit 20 , the display unit 40 and the pressure touch unit 30 in the touch display device are arranged in sequence.

As shown in FIG. 4 , in some embodiments, the force touch unit 30 may also be directly located on one side of the protective cover 10 . In this embodiment, the protective cover 10 , the pressure touch unit 30 , the capacitive touch unit 20 and the display unit 40 in the touch display device are arranged in sequence.

The pressure sensors 31 can be distributed at the corners of the pressure touch unit 30 . As shown in FIG. 1 , there are four pressure sensors 31 , which are respectively arranged at four ends of the flexible circuit board 32 , and the pressure sensors 31 are distributed at four corners of the touch display device.

The control chip of the pressure touch unit 30 can be integrated on the main board of the touch display device, or on the flexible circuit board 32 , and be electrically connected with the flexible circuit board 32 .

In the present invention, the pressure sensor 31 is combined and arranged on the flexible circuit board 32, and the circuit on the flexible circuit board 32 electrically conducts the pressure sensor 31 with the external control chip, and the integration degree of the pressure touch unit 30 can be improved in this way, which is convenient Subsequent assembly.

The specific structure and arrangement of the pressure touch control unit 30 will be further described below by taking the piezoelectric film sensor as an example for the pressure sensor 31 .

As shown in FIG. 5 and FIG. 6 , in an embodiment, the pressure touch unit 30 includes a piezoelectric film sensor 310 , a flexible circuit board 32 , and a control chip. The control chip may include components such as an operational amplifier 33, a single-chip microcomputer (including an A/D converter, not shown in the figure).

According to the specific setting position of the pressure touch unit 30, it can be connected with the casing (not shown), the protective cover 10, the capacitive touch unit 20 or the display unit of the touch display device through double-sided tape, water glue or foam glue. 40 fit.

In order to reduce the cost of the pressure touch unit 30 and improve the utilization rate of the flexible circuit board 32, the flexible circuit board 32 integrating the piezoelectric film sensor 310 can be integrated as a whole, or as shown in FIG. 5, include two or more The flexible circuit board 32 and the multiple flexible circuit boards 32 can be connected through a connection structure 320 such as a zero insertion force (ZIF) plug structure or a board-to-board (Board To Board, BTB) snap structure.

FIG. 6 is a schematic cross-sectional view of the connection between the flexible circuit board 32 and the piezoelectric film sensor 310 . The piezoelectric film sensor 310 includes a piezoelectric film 311 and an upper electrode 312 and a lower electrode 313 respectively located on two sides of the piezoelectric film 311 .

The flexible circuit board 32 includes two layers of double-sided metal cladding and glue for bonding the two layers of double-sided metal cladding. Specifically, the flexible circuit board 32 includes a first base layer 321, a first wiring layer 322, a first packaging layer 323, a second wiring layer 324, an adhesive layer 325, a third wiring layer 326, a second packaging layer 327 , a fourth circuit layer 328 and a second base layer 329 . The materials of the first base layer 321 , the first encapsulation layer 323 , the second encapsulation layer 327 and the second base layer 329 may be polyimide or polyester PET. The first wiring layer 322 , the second wiring layer 324 , the third wiring layer 326 and the fourth wiring layer 328 may be copper layers.

Wherein, the first encapsulation layer 323, the second encapsulation layer 327, and the adhesive layer 325 are provided with corresponding channels, so that some lines on the first circuit layer 322, the fourth circuit layer 328 and the second circuit layer 324 are conducted, and Ground treatment.

Holes 320 are provided at corresponding positions of the adhesive layer 325 to expose part of the second circuit layer 324 and the third circuit layer 326 . The piezoelectric film sensor 310 is arranged in the hole 320, and the upper electrode 312 of the piezoelectric film sensor 310 is connected to the second circuit layer 324 through the conductive glue 330, and the lower electrode 313 is connected to the third circuit layer 326 through another conductive glue 330. conduction.

When the piezoelectric film sensor 310 is integrated in the flexible circuit board 32, the first circuit layer 322 and the fourth circuit layer 328 in the flexible circuit board 32 serve as the shielding layer of the piezoelectric film sensor 310, due to the grounding of the shielding layer processing, the charge signal of the piezoelectric film sensor 310 will not be affected by the external electric field and magnetic field.

The operational amplifier 33 (including the charge primary and voltage secondary amplification circuits, not shown in the figure) and the single-chip microcomputer can be integrated on the flexible circuit board 32 or on the main board of the touch display device. In the embodiment shown in FIG. 5 , the operational amplifier 33 is integrated on the flexible circuit board 32 and is close to the interface port of the flexible circuit board 32 . The single chip microcomputer is arranged on the main board of the touch display device.

When the piezoelectric film 311 of the piezoelectric film sensor 310 is stressed, the upper and lower surfaces will generate induced charges, and the charge signal will be transmitted through the upper and lower electrodes 312, 313, and then through the conductive glue 330 and the second circuit in the flexible circuit board 32 Layer 324 and third wiring layer 326 transmit the charge signal to operational amplifier 33 . The signal amplified by the operational amplifier 33 is transmitted to the single-chip microcomputer for analog-to-digital conversion into a digital signal, and the corresponding relationship between the touch pressure and the signal is established.

When the user touches the touch display device with fingers or other conductors, due to the coupling capacitance between the user and the capacitive touch unit 20 of the touch display device, the capacitance of the capacitive touch unit 20 will change. The basic principle is to detect and obtain accurate position information of the touch point. At the same time, since the protective cover 10 of the touch display device is also subjected to force, the force is transmitted to the pressure touch unit 30, and the pressure touch unit 30 can detect the force component information of each pressure sensor 31. According to the selected pressure sensor The type of 31 is different, and the information may be voltage change information, capacitance change information, resistance change information, etc. According to the pressure information obtained by each pressure sensor 31, specific functions can be realized. For example, in one embodiment, the position information of the touch point can be accurately acquired according to the magnitudes of the four signals and the position of the pressure sensor 31 . When both the capacitive touch unit 20 and the pressure touch unit 30 acquire relevant information, the detection by the capacitive touch unit 20 shall prevail. When the capacitive touch unit 20 detects no signal but the pressure touch unit 30 detects a signal, the touch information acquired by the pressure touch unit 30 shall prevail. That is, the touch display device responds preferentially to the detection signal of the capacitive touch unit 20 . It should be pointed out that using the obtained pressure information to determine the position of the touch point is only an application of the pressure touch unit 30. In other implementations, other functions can be realized by using the obtained pressure information, such as in Operations in some applications can directly set the feedback on the magnitude of the pressure.

Usually, the piezoelectric film sensor 310 also needs to be provided with an encapsulation layer, a shielding layer and a base layer outside the upper and lower electrodes. Since the circuit layer (for example, the first circuit layer 322 and the fourth circuit layer 328 in FIG. The shielding layer in can be replaced by the shielding layer of the flexible circuit board 32 .

Fig. 6A is a further simplified embodiment of the structure of the embodiment described in Fig. 6, that is, the upper electrode 312 and the lower electrode 313 of the piezoelectric film 311 in Fig. and the lower double-sided conductive adhesive 330. As shown in FIG. 6A , the upper and lower conductive adhesives 330 are directly used as the upper and lower electrodes of the piezoelectric film 311 , which further simplifies the pressure touch unit.

The manufacturing method of the above-mentioned pressure touch unit 30 will be described below with reference to FIG. 7 to FIG. 11 .

As shown in Figure 7, the piezoelectric film sensor 310 includes a piezoelectric film 311, an upper electrode 312 and a lower electrode 313 located on both sides of the piezoelectric film 311, and an upper release film located outside the upper electrode 312 and the lower electrode 313 respectively. 314 and lower release film 315.

The materials of the piezoelectric film 311 include inorganic piezoelectric film materials and organic piezoelectric film materials, wherein the inorganic piezoelectric film materials can be zinc oxide films, aluminum-doped zinc oxide films, lead lanthanum zirconate titanate ceramic (PLZT) piezoelectric films and For other piezoelectric ceramic materials, the organic piezoelectric film can be polyvinylidene fluoride (PVDF), porous polypropylene piezoelectric film, polylactic acid piezoelectric film and other polyester piezoelectric films. Among them, the piezoelectric film is very thin, with a thickness of 0.05-2 μm.

The specific preparation steps of the piezoelectric film sensor 310 are as follows: provide a piezoelectric film; plate electrodes on both sides of the piezoelectric film by evaporation coating, magnetron sputtering coating, spray coating and other coating processes; Or other ways to obtain a circular, square or other fixed-shaped piezoelectric film element with upper and lower electrodes; cover the surface of the upper and lower electrodes with a release film. The piezoelectric film sensor 310 shown in FIG. 7 is thus formed. In the above preparation steps, the surface of the upper and lower electrodes can be coated with a release film first, and then die-cutting can be performed.

As shown in FIG. 8 , the flexible circuit board 32 sequentially includes a first base layer 321, a first circuit layer 322, a first packaging layer 323, a second circuit layer 324, an adhesive layer 325, a third circuit layer 326, The second encapsulation layer 327 , the fourth circuit layer 328 and the second base layer 329 . The hole 320 is provided at the position where the piezoelectric film sensor 310 is disposed, that is, the corresponding position of the adhesive layer 325 to expose part of the second circuit layer 324 and the third circuit layer 326 . Before the piezoelectric film sensor 310 is disposed on the flexible circuit board 32 , a conductive glue 330 is placed in the hole 320 to conduct with the second circuit layer 324 , and another conductive glue 330 is provided to conduct with the third circuit layer 326 . A release film 331 is disposed between the two conductive adhesives 330 .

Wherein, the first encapsulation layer 323, the second encapsulation layer 327 and the adhesive layer 325 are provided with corresponding channels, so that some lines on the first circuit layer 322, the fourth circuit layer 328 and the second circuit layer 324 are conducted, and After being applied to the touch display device, it is grounded.

As shown in FIG. 9 and FIG. 10 , it is a cross-sectional view and a front view of the interface end of the flexible circuit board 32 . At the interface end, the second circuit layer 324 connected to the upper electrodes 312 of each piezoelectric film sensor 310 on the flexible circuit board 32 is guided to the same plane as the third circuit layer 326 through corresponding channels, forming a plurality of signal antennae 333 , because four piezoelectric film sensors 310 are integrated on the flexible circuit board 32 , so there are four signal antennas 333 . In addition, some lines on the first line layer 322 , the fourth line layer 328 and the second line layer 324 are conducted and extended to form a ground contact 334 for grounding. Both the ground antenna 334 and the signal antenna 333 are on the same plane, so that they can be connected with external connectors.

In some embodiments, the interface end of the flexible circuit board 32 further forms a reinforcing plate 332 on the outside of the second base layer 329 . The reinforcing plate 332 is used to strengthen the physical strength of the interface end, so as to facilitate the connection with the external connector. The reinforcing plate 332 can be made of materials such as polyimide (PI) or polyethylene terephthalate (PET).

Referring to FIG. 11 , the detailed preparation steps of the flexible circuit board 32 of an embodiment are as follows: blanking, preparing the base material, drilling holes on the base material, then performing copper sinking and copper plating, applying a dry film, and exposing the copper layer Develop and etch, peel off the film to prepare the second circuit layer containing electrode patterns; prepare the third circuit layer containing electrode patterns on another substrate with the same steps as above; perform lamination and lamination protection on the second circuit layer and the third circuit layer ; Use glue to partially bond the two substrates (corresponding to the two encapsulation layers), wherein the electrode patterns of the second route layer and the third route layer are placed directly opposite to each other in parallel; drill the bonded two substrates out of the through hole for grounding, and carry out copper plating on the entire surface, that is, to form the first line layer and the fourth line layer, and at this time, some lines of the first line layer, the fourth line layer and the second line layer have been turned on; The surface of the first circuit layer and the fourth circuit layer is coated with PI material or PET material for lamination to form the first base layer and the second base layer; a reinforcing plate made of PI or PET is formed on the outside of the second base layer ; final blanking, and paste the upper and lower double-sided conductive adhesive with release film at the position for placing the piezoelectric film sensor (that is, the unbonded part of the two substrates), to obtain the structure shown in Figure 8 flexible circuit board. The prepared flexible circuit board is then packaged.

The integration steps of the piezoelectric film sensor 310 and the flexible circuit board 32 are as follows: the release film 331 in the flexible circuit board 32 shown in FIG. , the first encapsulation layer 323, the first circuit layer 322 and the first base layer 321) tear up a part, tear off the lower release film 315 in the piezoelectric film sensor 310 shown in Figure 7, and make the exposed piezoelectric film 311 is bonded with the conductive glue 330 located below the release film 331 in the flexible circuit board 32; The piezoelectric film 311 is bonded with another conductive adhesive 330 in the flexible circuit board 32 .

When the piezoelectric film sensor 310 is integrated into the flexible circuit board 32, the first circuit layer 322 and the fourth circuit layer 328 in the flexible circuit board 32 act as a shielding layer, and the external electric field will not be affected due to the grounding treatment of the shielding layer. The charge signal of the piezoelectric film sensor 310 .

The way of integrating the pressure sensor with the flexible circuit board can solve the problems of complex wiring and inconvenient installation when using multiple pressure sensors, and it can also be applied to the detection of the force of curved or multi-surface objects. At the same time, the double-sided conductive adhesive is used for bonding, which can quickly and conveniently realize the integration of the piezoelectric sensing element and the flexible circuit board at a relatively low temperature.

In some embodiments, for the piezoelectric film sensor in the pressure touch unit provided by the present invention, the upper and lower electrodes on both sides of the piezoelectric film can also use double-sided conductive adhesive materials. In addition to the connecting material of the flexible circuit board, it is also used as the electrode material of the piezoelectric film.

Although the piezoelectric film will generate induced charges on its surface after being stressed, the surface of the piezoelectric film is not conductive, so a conductive material is needed to transmit the induced charge signal on the surface. In addition to bonding the piezoelectric film to the flexible circuit board, the double-sided conductive adhesive also transmits the induced charge signal generated on the surface of the piezoelectric film through the circuit layer in the flexible circuit board. The area of the double-sided conductive adhesive is the same as the surface area of the piezoelectric film, or slightly smaller than the surface area of the piezoelectric film (that is, the double-sided conductive adhesive has a certain shrinkage).

On the other hand, in the touch display device provided by the present invention, the pressure touch unit is attached to the conductive substrate, and the conductivity and grounding properties of the substrate can be used to reduce the need for the piezoelectric film sensor to resist electromagnetic shielding. The shielding layer, thereby reducing the thickness of the pressure touch unit, thereby reducing the overall thickness of the touch display device. For example, the pressure touch unit can be pasted on the middle frame of the mobile phone or tablet computer through double-sided conductive adhesive, or on a display unit with a metal shell or a conductive layer on the surface, and the conductive layer can be used as a piezoelectric Electromagnetic shielding for thin-film sensors.

The pressure touch unit can detect the magnitude information of the force applied to the position of the piezoelectric film sensor through the multiple piezoelectric film sensors. At the same time, the pressure touch unit can integrate two or more piezoelectric film sensors through the flexible circuit board, so that it has the effect of simultaneously detecting the magnitude information of multiple forces, and at the same time simplifies the integration of multiple piezoelectric film sensors. The complexity of wiring and the complexity of assembly.

In one embodiment, the flexible circuit board in the pressure touch unit may have a two-layer circuit layer structure, one circuit layer is used as the electromagnetic shielding layer, and the other circuit layer is used as the signal layer of the piezoelectric film sensor. As shown in FIG. 12 , it is a schematic cross-sectional structure of a pressure touch control unit 50 that integrates a piezoelectric film sensor 510 on a flexible circuit board 52 .

The flexible circuit board 52 sequentially includes a first base layer 521 , a first circuit layer 522 , an adhesive layer 523 , a second circuit layer 524 and a second base layer 525 from top to bottom. The first base layer 521 and the second base layer 525 can be made of materials such as polyimide or polyester PET, and the first circuit layer 522 and the second circuit layer 524 can be made of copper layer or other metal/alloy materials. Holes 520 are provided at corresponding positions of the adhesive layer 523 to expose parts of the first circuit layer 522 and the second circuit layer 524 . The hole 520 is used for accommodating the piezoelectric film sensor 510 .

The piezoelectric film sensor 510 includes a piezoelectric film 511 and an upper conductive glue 512 and a lower conductive glue 513 respectively located on two sides of the piezoelectric film 511 . The upper conductive glue 512 is bonded with the first circuit layer 522, and the lower conductive glue 513 is bonded with the second circuit layer 524. The upper conductive glue 512 and the lower conductive glue 513 are used as the two electrodes of the piezoelectric film sensor 510, and also as the two electrodes of the piezoelectric film sensor 510. The connector of the flexible circuit board 52 , and transmits the induced charge signal generated by the piezoelectric film sensor 510 to the circuit layer of the flexible circuit board 52 . In the structure shown in FIG. 12, the first circuit layer 522 can be used as an electromagnetic shielding layer, which is a conductive layer on the entire surface, and through holes are set at appropriate positions of the adhesive layer 523, so that the first circuit layer 522 and the second circuit layer Partial wiring connections in the wiring layer 524 .

13 and 14 respectively show a cross-section and a front view of the flexible circuit board 52 at the interface end. After the first circuit layer 522 is connected to part of the circuits in the second circuit layer 524 , the ground antenna 534 is drawn out from the interface end of the flexible circuit board 52 . In addition, when the flexible circuit board 52 integrates multiple piezoelectric film sensors 510, the charge signal transmission of the multiple piezoelectric film sensors 510 all occurs in the second circuit layer 524, and a Signal antennae 533. Four signal antennae 533 are shown in FIG. 14 , and four piezoelectric film sensors 510 are integrated on the flexible circuit board 52 . In some embodiments, the interface end of the flexible circuit board 52 further forms a reinforcing plate 532 on the outside of the second base layer 525 . The reinforcing plate 532 is used to strengthen the physical strength of the interface end, so as to facilitate the connection with the external connector. The reinforcing plate 532 can be made of materials such as polyimide (PI) or polyethylene terephthalate (PET).

FIG. 15 is a schematic structural diagram of applying the pressure touch unit 50 to a touch display device. One side of the pressure touch unit 50 (such as the lower surface in FIG. 15 ) is bonded to the surface of the casing 90 of the touch display device through glue such as optical glue OCA, water glue, etc., and the conductive grounding treatment of the casing 90 It plays the role of electromagnetic shielding; at the same time, the other side of the pressure touch unit 50 (for example, the upper surface in FIG. 15 ) is attached to one side of the capacitive touch unit 20. The capacitive touch unit 20 can include Various capacitive touch solutions including cell and on-cell structures. Of course, in some embodiments, the other side of the pressure touch unit 50 can also be attached to one side of the protective cover, or attached to one side of the display module.

In other embodiments, the flexible circuit board in the pressure touch unit may have only one circuit layer, and a first base layer and a second base layer are respectively formed on both sides of the circuit layer. Since the circuit layer of the flexible circuit board is only used as a signal transmission layer for transmitting the charge signal generated by the piezoelectric film sensor, the pressure touch unit is applied to a touch display device that is conductive and grounded on both sides. In this method, the conductive structure of the touch display device is used to realize the electromagnetic shielding effect. This solution omits the electromagnetic shielding layer in the piezoelectric film sensor, so it has a smaller thickness.

Specifically as shown in FIG. 16 , the flexible circuit board 62 in the pressure touch unit 60 includes a first base layer 621 , a first circuit layer 622 and a second base layer 623 from top to bottom. The first base layer 621 and the second base layer 623 can be made of materials such as polyimide or polyester PET, and the first circuit layer 622 can be made of copper layer or other metal/alloy materials. Holes 620 are provided at corresponding positions of the second base layer 623 to expose part of the first wiring layer 622 . The hole 620 is used for accommodating the piezoelectric film sensor 610 .

The piezoelectric film sensor 610 includes a piezoelectric film 611 and an upper conductive glue 612 and a lower conductive glue 613 respectively located on two sides of the piezoelectric film 611 . The upper conductive adhesive 612 is bonded to the first circuit layer 622 . The lower conductive adhesive 613 is used for bonding with corresponding structures in the touch display device. The upper conductive glue 612 and the lower conductive glue 613 serve as two electrodes of the piezoelectric film sensor 610 .

17 and 18 respectively show a cross-section and a front view of the flexible circuit board 62 at the interface end. The first circuit layer 622 leads out the signal antennae 633 at the interface end of the flexible circuit board 62 . Since the first circuit layer 622 is only used for signal transmission and does not function as electromagnetic shielding, there is no corresponding circuit lead-out ground contactor. When the flexible circuit board 56 integrates multiple piezoelectric film sensors 610 , the charge signal transmission of the multiple piezoelectric film sensors 610 all occurs in the first circuit layer 622 . Five signal antennae 633 are shown in FIG. 18 , and five piezoelectric film sensors 610 are integrated on the flexible circuit board 62 . In some embodiments, the interface end of the flexible circuit board 62 further forms a reinforcing plate 632 on the outside of the second base layer 623 . The reinforcing plate 632 is used to strengthen the physical strength of the interface end, so as to facilitate the connection with the external connector. The reinforcing plate 632 can be made of materials such as polyimide (PI) or polyethylene terephthalate (PET).

FIG. 19 is a schematic structural diagram of applying the pressure touch control unit 60 to a touch display device. One side of the pressure touch unit 60 (such as the lower surface in FIG. 19 ) is attached to the surface of the casing 90 of the touch display device, and the conductive and grounded casing 90 acts as an electromagnetic shield; at the same time, the pressure The other side of the touch unit 60 (for example, the upper surface in FIG. 19 ) is bonded to one side of the display unit 40 with a metal frame by using glue 41 such as optical glue OCA, water glue, or the like. The grounding properties of the casing 90 and the display unit 40 are used to shield the interference of the surrounding electromagnetic environment on the piezoelectric film sensor 610 and the charge signal in the first circuit layer 622 of the flexible circuit board 62 . Further, an adhesive layer 91 such as foam glue, double-sided tape, etc. may be disposed between the casing 90 and the second base layer 623 of the flexible circuit board 62 to fix the flexible circuit board 62 and the casing 90 .

It can be understood that the above display unit 40 can also be a display module with a non-metal frame, but a conductive layer is plated on its surface and grounded. Understandably, in other embodiments, the other side of the pressure touch unit 60 can be attached to the capacitive touch unit, and the capacitive touch unit can be various types of capacitive touch solutions, or can be a capacitive touch control unit. Capacitive touch display module integrated with control and display module.

As shown in FIG. 20 , the piezoelectric film sensor 710 included in the pressure touch unit 70 provided by another embodiment of the present invention includes a piezoelectric film 711 , and upper electrodes 712 and lower electrodes 713 respectively located on both sides of the piezoelectric film 711 . Both the upper electrode 712 and the lower electrode 713 are conductive glue. The double-sided conductive adhesive on both sides of the piezoelectric film 711 not only serves as the upper and lower electrodes of the piezoelectric film, but also plays an adhesive role when assembling with the flexible circuit board 72 and other substrates. The surface area of the upper electrode 712 and the lower electrode 713 is the same as that of the piezoelectric film 711 , or slightly smaller than the surface area of the piezoelectric film 711 .

According to another embodiment of the present invention, the flexible circuit board 72 included in the pressure touch unit 70 includes, from top to bottom, a first base layer 721, a first circuit layer 722, a first packaging layer 723, a second circuit layer 724 and Second Base 725. The encapsulation layer and base layer can be made of materials such as polyimide or polyester PET. The first circuit layer 722 and the second circuit layer 724 may be copper layers or conductive layers of other metals or alloys. The first circuit layer 722 is a whole-surface conductive layer. By setting channels at the corresponding positions of the first encapsulation layer 723, the first circuit layer 722 is connected to some circuits in the second circuit layer 724, and grounded, so as to to the role of electromagnetic shielding. The second circuit layer 724 is the signal transmission layer of the flexible circuit board 72 , and the electrical signal generated by the piezoelectric film sensor 710 is transmitted to the interface port of the flexible circuit board 72 through the second circuit layer 724 . Holes 720 are disposed on the second base layer 725 for accommodating the piezoelectric film sensor 710 . The hole 720 exposes a portion of the second circuit layer 724 for connecting the upper electrode 712 of the piezoelectric film sensor 710 .

As shown in FIG. 21 and FIG. 22 , it is a cross-sectional view and a front view of the interface end of the flexible circuit board 72 . At the interface end, the second circuit layer 724 connected to the upper electrodes 712 of the piezoelectric film sensors 710 on the flexible circuit board 72 leads out a plurality of signal antennae 733 . In addition, the first circuit layer 722 conducts with some circuits in the second circuit layer 724 and leads out the ground antenna 734 for grounding. The ground contact 734 and the signal contact 733 are located on the same plane, so as to be able to connect with external connectors.

The induced charge generated by the piezoelectric film sensor 710 is transmitted to the second circuit layer 724 in the flexible circuit board 72 through the upper electrode 712; the lower electrode 713 is directly connected to the substrate of the touch display device, so that the piezoelectric film sensor 710 can realize To resist electromagnetic interference, the lower electrode 713 should be connected to a conductive grounding substrate to achieve a grounding effect, so the lower electrode 713 can be bonded to a metal or alloy casing, or bonded to a display unit with a metal frame, or coated with a metal Wait for the conductive layer and ground the display unit.

In the above-mentioned pressure touch unit 70, the first circuit layer 722 in the flexible circuit board 72 and the lower electrode 713 in the piezoelectric film sensor 710 are used as the ground shielding layer of the piezoelectric film sensor 710 to effectively reduce the pressure touch control. While the unit 70 is subjected to electromagnetic interference, the thickness of the pressure touch unit 70 is reduced.

The integration of the piezoelectric film sensor 710 and the flexible circuit board 72 in the present invention can simultaneously assemble a plurality of piezoelectric film sensors 710 into a flexible circuit board 72, and the charge signals generated by each piezoelectric film sensor 710 pass through the second circuit layer 724 is transmitted to the interface port of the flexible circuit board 72. The first circuit layer 722 is guided to part of the circuit of the second circuit layer 724 of the flexible circuit board 72 by providing a channel on the first packaging layer 723, thus finally connecting the signal antennae of the upper electrodes 712 of each piezoelectric film sensor 710 733 and the ground contactor 734 for grounding are located on the same plane at the interface end, so as to implement ZIF plug-in or BTB snap-in connection with another connector.

In some embodiments, the interface end of the flexible circuit board 32 further forms a reinforcing plate 732 on the outside of the first base layer 721 . The reinforcing plate 732 is used to strengthen the physical strength of the interface end, so as to facilitate the connection with the external connector. The reinforcing plate 732 can be made of materials such as polyimide (PI) or polyethylene terephthalate (PET).

The integration steps of the pressure touch unit 70 in the touch display device will be described below with reference to FIG. 23 . FIG. 23 shows that the piezoelectric film sensor 710 in the pressure touch unit 70 is bonded to the conductive substrate in the touch display device by means of the lower electrode 713 . The conductive substrate can be a conductive casing 90, or a display unit 40 with a metal frame, or a display unit 40 coated with a conductive layer. The second substrate 725 of the flexible circuit board 72 is bonded and fixed to the casing 90 or the display unit 40 through the adhesive layer 91 , such as foam glue, double-sided tape, and the like.

The integration method of the piezoelectric film sensor 710 and the flexible circuit board 72 contained in the pressure touch unit 70 may include the following process:

1. Preparation of the flexible circuit board. According to the process mentioned above, a flexible circuit board containing two circuit layers was prepared. Wherein the first circuit layer and the second circuit layer pass through the channel provided in the encapsulation layer, so that the first circuit layer and the part of the circuit in the second circuit layer are conducted, and the ground antenna is drawn out at the interface end of the flexible circuit board for grounded. The second wiring layer is designed according to the number and position of the planned integrated piezoelectric film sensors. A hole is provided at a suitable position of the second base layer to expose part of the second circuit layer, and the hole is used for installing a piezoelectric film sensor.

2. Attach the double-sided conductive adhesive to the two sides of the piezoelectric film respectively;

3. Attach the piezoelectric film with the upper and lower conductive adhesives to the hole of the flexible circuit board, and make one of the conductive adhesives adhere to the exposed second circuit layer; the above steps 2 and 3 are specific The sequence can be adjusted flexibly. For example, the conductive adhesive can be pasted on the hole of the flexible circuit board and bonded to the second circuit layer, and then the piezoelectric film can be pasted on the conductive adhesive;

4. Paste foam glue on the lower surface of the second base layer of the flexible circuit board, in which the piezoelectric film sensor on the flexible circuit board is exposed outside and not covered by the foam glue; then attach the pressure touch unit to the On a conductive case or a display unit with grounding treatment on the surface of the back cover, when the thickness of the foam glue is slightly larger than the thickness of the piezoelectric film sensor containing two layers of conductive adhesive, it can be set at the position where the case and the piezoelectric film sensor are connected. A raised structure; at the same time, by increasing the thickness of the piezoelectric film sensor and reducing the thickness of the foam glue, the thickness of the piezoelectric film sensor plus two layers of double-sided conductive adhesive is similar to the thickness of the foam glue. The shell or the display unit can be attached to the pressure touch unit without additionally providing a raised structure.

FIG. 24 and FIG. 25 show the specific application of the above pressure touch unit in a touch display device. The touch display device includes a casing 90 and a protective cover 10 , and the capacitive touch unit 20 , the display unit 40 and the pressure touch unit 70 are disposed in the cavity formed by the casing and the protective cover 10 . The pressure touch unit 70 can be disposed between the display unit 40 and the casing 90 . Wherein, the capacitive touch unit 20 may be an add-on touch solution, or may be an in-cell or on-cell structure solution, that is, the capacitive touch unit 20 and the display unit 40 are integrated. In some embodiments, the casing 90 is provided with a protrusion 92 at the position corresponding to the piezoelectric film sensor 710 of the pressure touch unit 70, so as to avoid the uneven height of the pressure touch unit 70 due to the use of adhesive layers and other structures. The problem affects the assembly accuracy. In order to reduce the impact of the protrusion 92 on the display effect of the display unit 40 when the screen is pressed, the display unit 40 preferably adopts a display module with a metal frame.

The various technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the various technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, should be considered as within the scope of this specification.

The above-mentioned embodiments only express several implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but should not be construed as limiting the patent scope of the invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (9)

1. a kind of pressure touch unit, it is characterised in that including flexible circuit board, the control core being electrically connected with flexible circuit board Piece and the piezoelectric film sensor being arranged on flexible circuit board, wherein：

The flexible circuit board includes the first base set gradually, first line layer, the first encapsulated layer, the second line layer, glue Adhesion coating, tertiary circuit layer, the second encapsulated layer, the 4th line layer and the second base, setting hole and exposed division on the adhesive layer The second line layer and tertiary circuit layer divided；

The piezoelectric film sensor include piezoelectric membrane and be located at piezoelectric membrane two sides top electrode and lower electrode, it is described Piezoelectric film sensor is arranged at the described hole of flexible circuit board, and the top electrode is connected with the second line layer, described Lower electrode is connected with tertiary circuit layer.

2. pressure touch unit according to claim 1, which is characterized in that the top electrode is with the second line layer by leading Electric glue conducting, the lower electrode are connected with tertiary circuit layer by another conducting resinl.

3. pressure touch unit according to claim 1, which is characterized in that first encapsulated layer, the second encapsulated layer, glue Corresponding channel is set on adhesion coating, so that the part line conduction on first line layer, the 4th line layer and the second line layer, and For grounding, make first line layer and the 4th line layer as electro-magnetic screen layer.

4. pressure touch unit according to claim 1, which is characterized in that the interface end of the flexible circuit board is second The outside of base also forms a stiffening plate.

5. a kind of touch control display apparatus, including pressure touch unit described in any one of claim 1-4.

6. a kind of production method of pressure touch unit, includes the following steps：

There is provided piezoelectric film sensor, including piezoelectric membrane, be located at piezoelectric membrane two sides top electrode and lower electrode, and The upper release film and lower release film being located on the outside of top electrode and lower electrode；

There is provided flexible circuit board, including set gradually the first base, first line layer, the first encapsulated layer, the second line layer, glue Adhesion coating, tertiary circuit layer, the second encapsulated layer, the 4th line layer and the second base, wherein hole is arranged in the corresponding position of adhesive layer And the second line layer and tertiary circuit layer of exposed portion, setting conducting resinl is connected with the second line layer at the hole, Yi Jiling One conducting resinl is connected with tertiary circuit layer, and release film is arranged between two conducting resinls；

By in piezoelectric film sensor upper release film and the removal of lower release film, and remove the release film in flexible circuit board, make Piezoelectric film sensor is arranged in hole, and top electrode and conductive adhesive, lower electrode and another conductive adhesive.

7. production method according to claim 6, which is characterized in that the preparation step of the piezoelectric film sensor includes： One piezoelectric membrane is provided；Top electrode and lower electrode are made respectively in the both side surface of piezoelectric membrane；Cross cutting is with upper/lower electrode Piezoelectric membrane；And upper release film, release film under being formed in lower electrode surface are formed in upper electrode surface.

8. production method according to claim 6, which is characterized in that the making step of the flexible circuit board includes：Prepare Substrate, and drill on substrate, then prepare the second line layer containing electrode pattern；Preparation contains electrode on another substrate The tertiary circuit layer of pattern；Laminate protection is carried out to the second line layer and tertiary circuit layer；Using gluing by two substrates Residual adhesion, wherein the second route layer and the electrode pattern of third route layer are that the parallel face of right opposite is placed；To the two of adhesion A substrate drill out the through-hole of ground connection, and forms first line layer and the 4th line layer, first line layer, the 4th line layer and The part line conduction of second line layer；The first base and the second base are formed on the surface of first line layer and the 4th line layer Layer；And punching, and the conducting resinl up and down with release film is sticked in the part of two non-adhesions of substrate.

9. production method according to claim 8, which is characterized in that the making step of the flexible circuit board further includes The step of re-forming stiffening plate on the outside of two bases.