WO2019185767A1 - Piezoelectric film detector and piezoelectric film sensor - Google Patents

Abstract

The present disclosure provides a piezoelectric film detector and a piezoelectric film sensor. The piezoelectric film detector includes the piezoelectric film sensor adapted to be adhered to a touch panel and to detect a click event applied onto the touch panel. The piezoelectric film sensor includes a plurality of piezoelectric films and is provided with an inner area defined by the plurality of piezoelectric films; and the piezoelectric film detector further includes a position determination device adapted to determine whether or not a position where the click event occurs is located within the inner area of the piezoelectric film sensor according to detection signals outputted from the plurality of piezoelectric films.

Description

PIEZOELECTRIC FILM DETECTOR AND PIEZOELECTRIC FILM SENSOR

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Chinese Patent Application No.

201810271729.0 filed on March 29, 2018 in the State Intellectual Property Office of China, the whole disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a piezoelectric film sensor and a piezoelectric film detector comprising the piezoelectric film sensor.

DESCRIPTION OF THE RELATED ART

In the related art, a piezoelectric film may be used to sense whether or not a click event is made by a hand on a surface (for example, on a touch panel). A mechanical wave will be generated when the hand clicks onto the surface and propagate through the surface, so that a piezoelectric film adhered onto the surface will generate electric charges due to stress, thus the electric charges of the piezoelectric film may be measured to detect whether or not a click event made by the hand occurs. However, by means of the piezoelectric film, it may only detect whether or not the click event occurs, but could not detect a specific position where the click event occurs.

SUMMARY

In an aspect, there is provided a piezoelectric film detector comprising a piezoelectric film sensor adapted to be adhered to a touch panel and to detect a click event applied onto the touch panel, the piezoelectric film sensor comprises a plurality of piezoelectric films and is provided with an inner area defined by the plurality of piezoelectric films, and the piezoelectric film detector further comprises a position determination device adapted to determine whether or not a position where the click event occurs is located within the inner area of the piezoelectric film sensor according to detection signals outputted from the plurality of piezoelectric films. Optionally, the piezoelectric film detector further comprises a signal processing device configured to process the detection signals outputted from the plurality of piezoelectric films; and the position determination device is configured to determine whether or not the position where the click event occurs is located within the inner area of the piezoelectric film sensor according to the processed detection signals.

Optionally, the position determination device is configured to calculate, according to the detection signals, a time difference between time points at which any two ones of the plurality of piezoelectric films detect the click event respectively; and the position determination device is further configured to determine whether or not the position where the click event occurs is located within the inner area of the piezoelectric film sensor according to the calculated time difference.

Optionally, the position determination device is further configured to determine that the position where the click event occurs is located within the inner area of the piezoelectric film sensor and not located within an outer area of the piezoelectric film sensor, when an absolute value of each of the calculated time differences is not greater than a first threshold Zl .

Optionally, the position determination device is further configured to determine that the position where the click event occurs is located within the outer area of the piezoelectric film sensor and not located within the inner area of the piezoelectric film sensor, when the absolute value of a particular one of the calculated time differences is greater than a second threshold Z2 greater than the first threshold Zl .

Optionally, the plurality of piezoelectric films comprises: an annular first piezoelectric film, the inner area being a circular inner area defined by the first piezoelectric film; and a circular second piezoelectric film centrally arranged in the inner area of the first piezoelectric film.

Optionally, the first threshold Zl is calculated according to the following formula (1):

Zl= R12/V (1),

where,

R12 is a radius of an inner circle of the annular first piezoelectric film, and

V is a propagation speed of a mechanical wave, which is generated by the click event on the touch panel, in the touch panel.

Optionally, the second threshold Z2 satisfies the following relational expression:

Zl<Z2< (Rl l-R2)/V (2),

where,

Rl 1 is a radius of an outer circle of the annular first piezoelectric film, and

R2 is a radius of the circular second piezoelectric film.

Optionally, the plurality of piezoelectric films comprises four rectangular piezoelectric films met and closed to form a square frame, the inner area being a square inner area defined by the four rectangular piezoelectric films.

Optionally, the first threshold Zl is calculated according to the following formula:

Zl= L2/V (3),

where,

L2 is a distance between inner side edges of two opposed ones of the piezoelectric films; and

V is a propagation speed of a mechanical wave, which is generated by the click event on the touch panel, in the touch panel.

Optionally, the second threshold Z2 satisfies the following relational expression (4):

ZKZ2< (Ll+L2)/2V (4),

where,

Ll is a distance between outer side edges of two opposed ones of the piezoelectric films.

In another aspect, there is provided a piezoelectric film sensor adapted to be adhered to a touch panel and to detect a click event applied onto the touch panel, the piezoelectric film sensor comprises a plurality of piezoelectric film and is provided with an inner area defined by the plurality of piezoelectric films.

Optionally, the plurality of piezoelectric films comprises: an annular first piezoelectric film, the inner area being a circular inner area defined by the first piezoelectric film; and a circular second piezoelectric film centrally arranged in the inner area of the first piezoelectric film.

Optionally, the plurality of piezoelectric films comprises four rectangular piezoelectric films met and closed to form a square frame, the inner area being a square inner area defined by the four rectangular piezoelectric films.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic diagram showing a piezoelectric film sensor according to an embodiment of the present disclosure;

Figure 2 is a schematic diagram showing that a click event occurs in an outer area of the piezoelectric film sensor shown in Figure 1;

Figure 3 is a schematic diagram showing that a click event occurs in an inner area of the piezoelectric film sensor shown in Figure 1;

Figure 4 is a schematic diagram showing a piezoelectric film sensor according to another embodiment of the present disclosure;

Figure 5 is a schematic diagram showing that a click event occurs in an outer area at one side of the piezoelectric film sensor shown in Figure 4;

Figure 6 is a schematic diagram showing that a click event occurs in an outer area at another side of the piezoelectric film sensor shown in Figure 4;

Figure 7 is a schematic diagram showing that a click event occurs in an inner area of the piezoelectric film sensor shown in Figure 4; and

Figure 8 is a schematic diagram showing a piezoelectric film detector according to an embodiment of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

Exemplary embodiments of the present disclosure will be described hereinafter in detail with reference to the attached drawings, wherein the like reference numerals refer to the like elements. The present disclosure may, however, be embodied in many different forms and should not be construed as being limited to the embodiment set forth herein; rather, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the concept of the disclosure to those skilled in the art.

In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.

According to a general technical concept of the present disclosure, there is provided a piezoelectric film detector including a piezoelectric film sensor adapted to be adhered to a touch panel and to detect a click event applied onto the touch panel, the piezoelectric film sensor includes a plurality of piezoelectric films and is provided with an inner area which is defined by the plurality of piezoelectric films, and the piezoelectric film detector further includes a position determination device adapted to determine whether or not a position where the click event occurs is located within the inner area of the piezoelectric film sensor according to detection signals outputted from the plurality of piezoelectric films.

According to a further general technical concept of the present disclosure, there is provided a piezoelectric film sensor adapted to be adhered to a touch panel and to detect a click event applied onto the touch panel, the piezoelectric film sensor includes a plurality of piezoelectric film and is provided with an inner area which is defined by the plurality of piezoelectric films.

Figure 1 is a schematic diagram showing a piezoelectric film sensor according to an embodiment of the present disclosure; Figure 2 is a schematic diagram showing that a click event occurs in an outer area of the piezoelectric film sensor shown in Figure 1; Figure 3 is a schematic diagram showing that a click event occurs in an inner area of the piezoelectric film sensor shown in Figure 1.

In the illustrated embodiment, as shown in Figure 1 to Figure 3, the piezoelectric film sensor is adapted to be adhered to a touch panel 10 and to detect a click event applied onto the touch panel 10.

In an embodiment of the present disclosure, as shown in Figure 8, disclosed is a piezoelectric film detector 100 including the illustrated piezoelectric film sensor 110 and configured for detecting a position where the click event occurs. The piezoelectric film detector 100 may further include a signal processing device 120 and a position determination device 130.

In the illustrated embodiments, as shown in Figure 1 to Figure 3, the piezoelectric film sensor includes a plurality of piezoelectric films Cl, C2 and is provided with an inner area which is defined by the plurality of piezoelectric films Cl, C2. The position determination device 130 is adapted to determine whether or not the position where the click event occurs is located within the inner area of the piezoelectric film sensor according to detection signals outputted from the plurality of piezoelectric films Cl, C2.

In the illustrated embodiments, as shown in Figure 1 to Figure 3, the piezoelectric film sensor includes an annular first piezoelectric film Cl and a circular second piezoelectric film C2. The inner area is a circular inner area defined by the first piezoelectric film Cl. The circular second piezoelectric film C2 is centrally arranged in the inner area of the first piezoelectric film Cl .

Optionally, the signal processing device 120 is configured to process the detection signals outputted from the plurality of piezoelectric films Cl, C2. The position determination device 130 is configured to determine whether or not the position where the click event occurs is located within the inner area of the piezoelectric film sensor according to the processed detection signals.

As shown in Figure 3, when a click event occurs in the inner area of the piezoelectric film sensor shown in Figure 1 , a mechanical wave is generated, a time point at which the first piezoelectric film Cl detects the click event (i.e., the mechanical wave) is Tl, and a time point at which the second piezoelectric film C2 detects the click event is T2. In this case, a time difference between the time points at which the first and second piezoelectric films Cl, C2 detect the click event respectively is T2-T1. As shown in Figure 1 and Figure 3, it may be deduced that an absolute value, |T2-Tl |, of the T2-T1 is not greater than a first threshold Zl, which may be calculated according to the following formula (1):

Zl= R12/V (1),

where,

R12 is a radius of an inner circle of the annular first piezoelectric film Cl, and

V is a propagation speed of a mechanical wave, which is generated by the click event on the touch panel 10, in the touch panel 10.

In the illustrated embodiments, as shown in Figure 1 and Figure 3, if the absolute value

|T2-Tl | of the calculated time difference is not greater than the first threshold Zl, the position determination device may determine that the position where the click event occurs is located within the inner area of the piezoelectric film sensor and not located within an outer area of the piezoelectric film sensor.

As shown in Figure 2, when a click event occurs in the outer area of the piezoelectric film sensor shown in Figure 1, a time point at which the first piezoelectric film Cl detects the click event is Tl, and a time point at which the second piezoelectric film C2 detects the click event is T2. In this case, a time difference between the time points at which the first and second piezoelectric films Cl, C2 detect the click event respectively is T2-T1. As shown in Figure 1 and Figure 2, it may be deduced that an absolute value, |T2-Tl |, of the T2-T1 is greater than a second threshold Z2 greater than the first threshold Zl, which second threshold Z2 satisfies the following relational expression:

Zl<Z2< (Rll-R2)/V (2),

where,

Rll is a radius of an outer circle of the annular first piezoelectric film Cl, and

R2 is a radius of the circular second piezoelectric film C2.

It should be noted that, in the embodiment, sizes of the annular first piezoelectric film Cl and the circular second piezoelectric film C2 may be designed to satisfy“R11-R2” is greater than“R12”.

In the illustrated embodiments, as shown in Figure 1 and Figure 2, if the absolute value |T2-Tl | of the calculated time difference is greater than the second threshold Z2 greater than the first threshold Zl, the position determination device may determine that the position where the click event occurs is located within the outer area of the piezoelectric film sensor and not located within the inner area of the piezoelectric film sensor.

In an embodiment of the present disclosure, the signal processing device 120 may process, for example, amplify or shape, the detection signals outputted from the plurality of piezoelectric films Cl, C2.

In an embodiment of the present disclosure, the position determination device 130 may include a microprocessor or computer which can recognize the position of the click event occurs through internal algorithms thereof.

Figure 4 is a schematic diagram showing a piezoelectric film sensor according to another embodiment of the present disclosure; Figure 5 is a schematic diagram showing that a click event occurs in an outer area at one side of the piezoelectric film sensor shown in Figure 4; Figure 6 is a schematic diagram showing that a click event occurs in an outer area at another side of the piezoelectric film sensor shown in Figure 4; and Figure 7 is a schematic diagram showing that a click event occurs in an inner area of the piezoelectric film sensor shown in Figure 4.

In the illustrated embodiments, as shown in Figure 4 to Figure 7, the piezoelectric film sensor is adapted to be adhered to a touch panel 10 and to detect a click event applied onto the touch panel 10.

In an embodiment of the present disclosure, disclosed is a piezoelectric film detector including the illustrated piezoelectric film sensor and configured for detecting a position where the click event occurs.

In the illustrated embodiments, as shown in Figure 4 to Figure 7, the piezoelectric film sensor includes a plurality of piezoelectric films Fl, F2, F3, F4 and is provided with an inner area which is defined by the plurality of piezoelectric films Fl, F2, F3, F4. The piezoelectric film detector further includes a position determination device 130 adapted to determine whether or not the position where the click event occurs is located within the inner area of the piezoelectric film sensor according to detection signals outputted from the plurality of piezoelectric films Fl, F2, F3, F4.

In the illustrated embodiments, as shown in Figure 4 to Figure 7, the piezoelectric film sensor includes four rectangular piezoelectric films Fl, F2, F3, F4. The four rectangular piezoelectric films Fl , F2, F3, F4 are met and closed to form a square frame. The inner area is a square inner area defined by the four rectangular piezoelectric films Fl, F2, F3, F4.

Optionally, the signal processing device 120 is configured to process the detection signals outputted from the plurality of piezoelectric films Fl, F2, F3, F4. The position determination device 130 is configured to determine whether or not the position where the click event occurs is located within the inner area of the piezoelectric film sensor according to the processed detection signals.

As shown in Figure 7, when a click event occurs in the inner area of the piezoelectric film sensor shown in Figure 4, a time point at which the first piezoelectric film Fl detects the click event is T 1 , a time point at which the second piezoelectric film F2 detects the click event is T2, a time point at which the third piezoelectric film F3 detects the click event is T3, and a time point at which the fourth piezoelectric film F4 detects the click event is T4. In this case, time differences between the time points at which two piezoelectric films detect the click event respectively may be expressed as T2-T1, T3-T1, T4-T1, T3-T2, T4-T2, T4- T3. As shown in Figure 4 and Figure 7, it may be deduced that an absolute value of each of those time differences T2-T1, T3-T1, T4-T1, T3-T2, T4-T2, T4-T3 is not greater than a first threshold Zl, which may be calculated according to the following formula (3):

Zl= L2/V (3),

where,

L2 is a distance between inner side edges of two opposed ones of the piezoelectric films Fl, F3; F2, F4; and

V is a propagation speed of a mechanical wave, which is generated by the click event on the touch panel 10, in the touch panel 10.

In the illustrated embodiments, as shown in Figure 4 and Figure 7, if the absolute value of each of the calculated time differences is not greater than the first threshold Zl, the position determination device may determine that the position where the click event occurs is located within the inner area of the piezoelectric film sensor and not located within an outer area of the piezoelectric film sensor.

In the embodiment shown in Figure 7, the absolute value |T3-T 11 of the time difference T3-T1 is the largest, and if |T3-Tl | is not greater than the first threshold Zl, the position determination device may determine that the position where the click event occurs is located within the inner area of the piezoelectric film sensor and not located within the outer area of the piezoelectric film sensor.

As shown in Figure 5 and Figure 6, when a click event occurs in the outer area of the piezoelectric film sensor shown in Figure 4, a time point at which the first piezoelectric film Fl detects the click event is Tl, a time point at which the second piezoelectric film F2 detects the click event is T2, a time point at which the third piezoelectric film F3 detects the click event is T3, and a time point at which the fourth piezoelectric film F4 detects the click event is T4. In this case, time differences between the time points at which two piezoelectric films detect the click event respectively may be expressed as T2-T1, T3-T1, T4-T1, T3-T2, T4-T2, T4-T3. As shown in Figure 4, Figure 5 and Figure 6, it may be deduced that an absolute value of a particular one of those time differences T2-T1, T3-T1, T4-T1, T3-T2, T4-T2, T4-T3 is necessarily greater than a second threshold Z2 greater than the first threshold Zl, which second threshold Z2 satisfies the following relational expression (4):

ZKZ2< (Ll+L2)/2V (4),

where,

Ll is a distance between outer side edges of two opposed ones of the piezoelectric films Fl, F3; F2, F4.

In the illustrated embodiments, as shown in Figure 4, Figure 5 and Figure 6, if the absolute value of a particular one of those time differences is greater than the second threshold Z2 greater than the first threshold Zl, the position determination device may determine that the position where the click event occurs is located within the outer area of the piezoelectric film sensor and not located within the inner area of the piezoelectric film sensor.

In the embodiment shown in Figure 5, the absolute value |T3-T 11 of the time difference T3-T1 is the largest, and if |T3-Tl | is greater than the second threshold Z2, the position determination device may determine that the position where the click event occurs is not located within the inner area of the piezoelectric film sensor but located within the outer area of the piezoelectric film sensor.

In the embodiment shown in Figure 6, the absolute value |T4-T2| of the time difference T4-T2 is the largest, and if |T4-T2| is greater than the second threshold Z2, the position determination device may determine that the position where the click event occurs is not located within the inner area of the piezoelectric film sensor but located within the outer area of the piezoelectric film sensor.

In embodiments of the present disclosure, the signal processing device 120 may process, for example, amplify or shape, the detection signals outputted from the plurality of piezoelectric films Fl, F2, F3, F4.

In an embodiment of the present disclosure, the position determination device 130 may include a microprocessor or computer which can recognize the position of the click event occurs through internal algorithms thereof.

In exemplary embodiments of the present disclosure described herein, the piezoelectric film sensor includes a plurality of piezoelectric films and is provided with an inner area, and may determine whether or not the position of the click event occurs is located within the inner area of the piezoelectric film sensor according to detection signals outputted from the plurality of piezoelectric films, thereby enabling recognition of the position of the click event occurs. Thus, it enables recognition of the position of the click event occurs with a low cost.

It should be appreciated by those skilled in this art that the above embodiments are intended to be illustrative, and many modifications may be made to the above embodiments by those skilled in this art, and various structures described in various embodiments may be freely combined with each other without conflicting in configuration or principle.

Although the present disclosure have been described hereinbefore in detail with reference to the attached drawings, it should be appreciated that the disclosed embodiments in the attached drawings are intended to illustrate the preferred embodiments of the present disclosure by way of example, and should not be construed as limitation to the present disclosure.

Although several exemplary embodiments have been shown and described, it would be appreciated by those skilled in the art that various changes or modifications may be made to these embodiments without departing from the principles and spirit of the disclosure, the scope of which is defined by the claims and their equivalents.

It should be noted that, the word“comprise” doesn’t exclude other elements or steps, and the word“a” or“an” doesn’t exclude more than one. In addition, any reference numerals in the claims should not be interpreted as the limitation to the scope of the present disclosure.

Claims

WHAT IS CLAIMED IS:

1. A piezoelectric film detector, comprising:

a piezoelectric film sensor adapted to be adhered to a touch panel (10) and to detect a click event applied onto the touch panel (10),

wherein, the piezoelectric film sensor comprises a plurality of piezoelectric films (Cl, C2) and is provided with an inner area defined by the plurality of piezoelectric films; and the piezoelectric film detector further comprises a position determination device adapted to determine whether or not a position where the click event occurs is located within the inner area of the piezoelectric film sensor according to detection signals outputted from the plurality of piezoelectric films (Cl, C2).

2. The piezoelectric film detector according to claim 1, wherein

the piezoelectric film detector further comprises a signal processing device configured to process the detection signals outputted from the plurality of piezoelectric films (Cl, C2); and

the position determination device is configured to determine whether or not the position where the click event occurs is located within the inner area of the piezoelectric film sensor according to the processed detection signals.

3. The piezoelectric film detector according to claim 1 or 2, wherein

the position determination device is configured to calculate, according to the detection signals, a time difference between time points at which any two ones of the plurality of piezoelectric films (Cl, C2) detect the click event respectively; and

the position determination device is further configured to determine whether or not the position where the click event occurs is located within the inner area of the piezoelectric film sensor according to the calculated time difference.

4. The piezoelectric film detector according to claim 3, wherein

the position determination device is further configured to determine that the position where the click event occurs is located within the inner area of the piezoelectric film sensor and not located within an outer area of the piezoelectric film sensor, when an absolute value of each of the calculated time differences is not greater than a first threshold Zl .

5. The piezoelectric film detector according to claim 4, wherein

the position determination device is further configured to determine that the position where the click event occurs is located within the outer area of the piezoelectric film sensor and not located within the inner area of the piezoelectric film sensor, when the absolute value of a particular one of the calculated time differences is greater than a second threshold Z2 greater than the first threshold Zl .

6. The piezoelectric film detector according to claim 5, wherein the plurality of piezoelectric films comprises:

an annular first piezoelectric film (Cl), the inner area being a circular inner area defined by the first piezoelectric film (Cl); and

a circular second piezoelectric film (C2) centrally arranged in the inner area of the first piezoelectric film (Cl).

7. The piezoelectric film detector according to claim 6, wherein the first threshold Zl is calculated according to the following formula (1):

Zl= R12/V (1),

where,

R12 is a radius of an inner circle of the annular first piezoelectric film (Cl), and V is a propagation speed of a mechanical wave, which is generated by the click event on the touch panel (10), in the touch panel (10).

8. The piezoelectric film detector according to claim 7, wherein the second threshold Z2 satisfies the following relational expression:

Zl<Z2< (Rl l-R2)/V (2),

where, Rll is a radius of an outer circle of the annular first piezoelectric film (Cl), and

R2 is a radius of the circular second piezoelectric film (C2).

9. The piezoelectric film detector according to claim 5, wherein the plurality of piezoelectric films comprises:

four rectangular piezoelectric films (Fl, F2, F3, F4) met and closed to form a square frame, the inner area being a square inner area defined by the four rectangular piezoelectric films (Fl, F2, F3, F4).

10. The piezoelectric film detector according to claim 9, wherein the first threshold Zl is calculated according to the following formula:

Zl= L2/V (3),

where,

L2 is a distance between inner side edges of two opposed ones of the piezoelectric films (Fl, F3; F2, F4); and

V is a propagation speed of a mechanical wave, which is generated by the click event on the touch panel (10), in the touch panel (10).

11. The piezoelectric film detector according to claim 10, wherein the second threshold Z2 satisfies the following relational expression (4):

ZKZ2< (Ll+L2)/2V (4),

where,

Ll is a distance between outer side edges of two opposed ones of the piezoelectric films (Fl, F3; F2, F4).

12. A piezoelectric film sensor adapted to be adhered to a touch panel (10) and to detect a click event applied onto the touch panel (10),

wherein the piezoelectric film sensor comprises a plurality of piezoelectric films (Cl, C2) and is provided with an inner area defined by the plurality of piezoelectric films (Cl, C2).

13. The piezoelectric film detector according to claim 12, wherein the plurality of piezoelectric films comprises:

an annular first piezoelectric film (Cl), the inner area being a circular inner area defined by the first piezoelectric film (Cl); and

a circular second piezoelectric film (C2) centrally arranged in the inner area of the first piezoelectric film (Cl).

14. The piezoelectric film detector according to claim 12, wherein the plurality of piezoelectric films comprises:

four rectangular piezoelectric films (Fl, F2, F3, F4) met and closed to form a square frame, the inner area being a square inner area defined by the four rectangular piezoelectric films (Fl, F2, F3, F4).