CN108375431B - Pressure detection circuit, pressure detection method, pressure detection module and display device - Google Patents
Pressure detection circuit, pressure detection method, pressure detection module and display device Download PDFInfo
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- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/16—Measuring force or stress, in general using properties of piezoelectric devices
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- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
- G01L9/08—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of piezoelectric devices, i.e. electric circuits therefor
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Abstract
The invention provides a pressure detection circuit, a pressure detection method, a pressure detection module and a display device. The pressure detection circuit comprises a pressure detection output end, a piezoelectric sensing unit, a piezoelectric signal conversion unit, a current mirror, an energy storage unit and an output control unit, wherein the output end of the current mirror is connected with a first end of the energy storage unit, and a second end of the energy storage unit is connected with a first level input end; the control end of the output control unit is connected with the corresponding row strobe line, and the output control unit is used for controlling the connection or disconnection between the output end of the current mirror and the pressure detection output end under the control of the corresponding row strobe line. The invention can be applied to array type multipoint pressure detection.
Description
Technical Field
The invention relates to the technical field of pressure detection, in particular to a pressure detection circuit, a pressure detection method, a pressure detection module and a display device.
Background
The existing pressure detection circuit comprises a piezoelectric sensing unit, a storage capacitor and a switching transistor, wherein the grid electrode of the switching transistor is connected with the piezoelectric sensing unit, and a direct-current voltage source is connected to the grid electrode of the switching transistor through a resistor, so that a bias voltage is provided for the grid electrode of the switching transistor. The drain electrode of the switch transistor is connected with a high voltage VDD through a resistor, and the source electrode of the switch transistor is grounded; the first end of the storage capacitor is connected with the grid electrode of the switch transistor, and the other end of the storage capacitor is grounded. When the piezoelectric sensing unit receives pressure, a surge is instantaneously generated in the gate voltage of the switching transistor, so that the drain-source current Ids of the switching transistor changes, and thus the voltage output by the drain of the switching transistor also changes. The conventional pressure detection circuit cannot hold pressure information, and is only suitable for a framework for detecting a single pressure in real time, but if a plurality of pressure sensing units exist, for example, an array type multipoint pressure detection, a mode capable of holding the pressure information is required.
Disclosure of Invention
The invention mainly aims to provide a pressure detection circuit, a pressure detection method, a pressure detection module and a display device, and solves the problem that the existing pressure detection circuit is suitable for a framework for detecting single pressure sense in real time and cannot be applied to array type multipoint pressure detection.
In order to achieve the above object, the present invention provides a pressure detection circuit, which comprises a pressure detection output terminal, a piezoelectric sensing unit, a piezoelectric signal conversion unit, a current mirror, an energy storage unit and an output control unit, wherein,
the piezoelectric sensing unit is used for sensing pressure, converting a pressure signal into a piezoelectric signal and outputting the piezoelectric signal through a piezoelectric sensing output end;
the input end of the piezoelectric signal conversion unit is connected with the piezoelectric induction output end, the output end of the piezoelectric signal conversion unit is connected with the input end of the current mirror, and the piezoelectric signal conversion unit is used for converting the piezoelectric signal into a corresponding pressure-sensitive current signal and outputting the pressure-sensitive current signal through the output end;
the output end of the current mirror is connected with the first end of the energy storage unit, and the second end of the energy storage unit is connected with the first level input end;
the control end of the output control unit is connected with the corresponding row strobe line, and the output control unit is used for controlling the connection or disconnection between the output end of the current mirror and the pressure detection output end under the control of the corresponding row strobe line.
In practice, the pressure signal conversion unit comprises:
a grid electrode of the pressure signal conversion transistor is connected with the piezoelectric induction output end, a first pole of the pressure signal conversion transistor is connected with the input end of the current mirror, and a second pole of the pressure signal conversion transistor is connected with a second level input end; and the number of the first and second groups,
the bias voltage providing resistor is connected with a direct-current voltage end at a first end and connected with a grid electrode of the pressure signal conversion transistor at a second end;
the piezoelectric induction unit comprises a first polar plate, a second polar plate and a piezoelectric material layer positioned between the first polar plate and the second polar plate;
the first polar plate is connected with a third level input end, and the second polar plate is connected with the piezoelectric induction output end.
In practice, the current mirror includes an input transistor and an output transistor, wherein,
a gate of the input transistor is connected to a gate of the output transistor, a first pole of the input transistor and a first pole of the output transistor are both connected to a first voltage input terminal, and a second pole of the input transistor is connected to the gate of the input transistor; the second pole of the input transistor is the input end of the current mirror;
the second pole of the output transistor is the output end of the current mirror;
the energy storage unit includes: a first end of the holding capacitor is connected with the output end of the current mirror, and a second end of the holding capacitor is connected with the first level input end;
the output control unit includes: and the grid of the output control transistor is connected with the corresponding row strobe line, the first pole of the output control transistor is connected with the output end of the current mirror, and the second pole of the output control transistor is connected with the pressure detection output end.
In practice, the pressure detection circuit of the present invention further comprises a mirror transistor and a mirror resistor, wherein,
the first end of the mirror resistor is connected with the direct-current voltage end;
the grid electrode of the mirror image transistor is connected with the second end of the mirror image resistor, the first pole of the mirror image transistor is connected with the output end of the current mirror, and the second pole of the mirror image transistor is connected with the second level input end;
the resistance value of the mirror resistor is equal to that of the bias voltage supply resistor;
the width-to-length ratio of the mirror transistor is equal to that of the pressure signal conversion transistor;
the current value of the pressure-sensitive current signal input by the input end of the current mirror is equal to the current value of the charging current signal output by the output end of the current mirror;
the mirror image transistor and the pressure signal conversion transistor are both n-type transistors, or the mirror image transistor and the pressure signal conversion transistor are both p-type transistors.
In practice, the pressure detection circuit of the present invention further comprises: and the pressure detection unit is connected with the pressure detection output end and used for detecting whether the piezoelectric sensing unit senses pressure according to the voltage signal output by the pressure detection output end and detecting the pressure value of the pressure according to the voltage signal when the piezoelectric sensing unit senses the pressure.
The invention also provides a pressure detection method, which is applied to the pressure detection circuit and comprises the following steps:
in a pressure detection stage, the piezoelectric sensing unit senses pressure, converts a pressure signal into a piezoelectric signal and outputs the piezoelectric signal through a piezoelectric sensing output end; the piezoelectric signal conversion unit converts the piezoelectric signal into a corresponding pressure-sensitive current signal and outputs the pressure-sensitive current signal to the input end of the current mirror; the current mirror converts a pressure-sensitive current signal input through an input end of the current mirror into a charging current signal; the current mirror outputs the charging current signal to a first end of the energy storage unit through an output end of the current mirror so as to charge the energy storage unit through the charging current signal; the output control unit controls the disconnection between the output end of the current mirror and the pressure detection output end under the control of the corresponding row strobe line;
at the moment of reading, the output control unit controls and conducts the connection between the output end of the current mirror and the pressure detection output end under the control of the corresponding row strobe line;
the reading time is the time which is arranged after the pressure detection stage and is close to the ending time of the pressure detection stage.
In practice, the pressure detection method of the present invention further comprises: at an initial moment, the output control unit controls and conducts the connection between the output end of the current mirror and the pressure detection output end so as to reset the potential of the output end of the current mirror to an initial voltage;
the initial time is a time immediately before the pressure detection stage and immediately before the start time of the pressure detection stage.
In practice, the pressure detection circuit further comprises a pressure detection unit; the pressure detection method further includes:
the pressure detection unit detects whether the piezoelectric sensing unit senses pressure according to the voltage signal output by the pressure detection output end at the reading moment, and detects the pressure value of the pressure according to the voltage signal when the piezoelectric sensing unit senses the pressure.
The invention also provides a pressure detection module, which comprises a plurality of rows of gate lines, a plurality of columns of reading lines and a plurality of rows and columns of pressure detection circuits arranged in an array;
the pressure detection circuit on the same row comprises an output control unit, the control end of which is connected with the gate line on the same row;
and the pressure detection output ends of the pressure detection circuits positioned in the same column are connected with the reading lines in the same column.
The invention also provides a display device which comprises the pressure detection module.
Compared with the prior art, the pressure detection circuit, the pressure detection method, the pressure detection module and the display device can be suitable for detecting single-point pressure detection and array type multi-point pressure detection (as the pressure detection circuit can keep the piezoelectric signals converted by the piezoelectric sensing unit).
Drawings
FIG. 1 is a block diagram of a pressure sensing circuit according to an embodiment of the present invention;
FIG. 2 is a block diagram of a pressure sensing circuit according to another embodiment of the present invention;
FIG. 3 is a block diagram of a pressure sensing circuit according to yet another embodiment of the present invention;
FIG. 4 is a circuit diagram of a first embodiment of a pressure sensing circuit according to the present invention;
FIG. 5 is a diagram illustrating the voltage VB at the output node B and the drain-source current Ids at T1 when the first embodiment of the pressure sensing circuit of the present invention is in operation (the horizontal axis in FIG. 5 is time T);
fig. 6 is a circuit diagram of a first embodiment of the pressure detection circuit according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1, the pressure detection circuit according to the embodiment of the present invention includes a pressure detection output terminal Vou, a piezoelectric sensing unit 11, a piezoelectric signal conversion unit 12, a current mirror 13, an energy storage unit 14, and an output control unit 15, wherein,
the piezoelectric sensing unit 11 is used for sensing pressure, converting a pressure signal into a piezoelectric signal, and outputting the piezoelectric signal through a piezoelectric sensing output end; the piezoelectric induction output end is connected with a piezoelectric node FD;
the input end of the piezoelectric signal conversion unit 12 is connected to the piezoelectric sensing output end (that is, the input end of the piezoelectric signal conversion unit 12 is connected to the piezoelectric node FD), the output end of the piezoelectric signal conversion unit 12 is connected to the input end of the current mirror 13, and the piezoelectric signal conversion unit 12 is configured to convert the piezoelectric signal into a corresponding pressure-sensing current signal and output the pressure-sensing current signal through the output end;
the input end of the current mirror 13 is connected with an input node A, and the output end of the current mirror 13 is connected with an output node B;
the output end of the current mirror 13 is connected to a first end of the energy storage unit 14 (that is, the output end of the current mirror 13 is connected to the output node B), and a second end of the energy storage unit 14 is connected to a first level input end VI 1;
the control end of the output control unit 15 is connected to a corresponding row strobe line SEL, and the output control unit 15 is configured to control the connection between the output end of the current mirror 13 and the pressure detection output end Vou to be turned on or off under the control of the corresponding row strobe line SEL.
In practical implementation, the first level input terminal VI1 may be a ground terminal, or may be a low level input terminal, but not limited thereto, and in actual operation, the voltage value of the first level input by VI1 may be selected according to actual situations.
The pressure detection circuit according to the embodiment of the present invention converts the received pressure signal into a piezoelectric signal through the piezoelectric sensing unit 11, converts the piezoelectric signal into a corresponding pressure-sensitive current signal through the piezoelectric signal conversion unit 12, inputs the pressure-sensitive current signal into the input end of the current mirror 13, charges the energy storage unit 14 through the charging current signal output from the output end of the current mirror 13, so that the piezoelectric signal converted by the piezoelectric sensing unit 11 in the pressure detection stage can be maintained by the energy storage unit 14 and the current mirror 13 together, and at the reading time (the reading time is the time immediately adjacent to the end time of the pressure detection stage after the pressure detection stage), the output control unit 15 controls the connection of the output end of the current mirror 13 and the pressure detection output end under the control of the corresponding row select line SEL, and judging whether the piezoelectric sensing unit 11 senses the pressure in the pressure detection stage according to the voltage signal output by the pressure detection output end at the reading moment.
The pressure detection circuit provided by the embodiment of the invention can be suitable for detecting the pressure of a single point, and can be further suitable for array type multi-point pressure detection (as the pressure detection circuit provided by the embodiment of the invention can keep the piezoelectric signal converted by the piezoelectric sensing unit).
In the pressure detection circuit according to the embodiment of the present invention, a ratio between a current value of the voltage-sensitive current signal input from the input terminal of the current mirror 13 and a current value of the charging current signal output from the output terminal of the current mirror 13 is fixed, and the ratio is related to a ratio between a width-to-length ratio of the input transistor included in the current mirror 13 and a width-to-length ratio of the output transistor included in the current mirror 13.
In actual operation, the piezoelectric sensing unit 11 converts a pressure signal to obtain a piezoelectric signal, which is a voltage difference signal, when the piezoelectric sensing unit 11 is under pressure, a voltage output by a piezoelectric sensing output end of the piezoelectric sensing unit changes, a voltage difference signal between the voltage and a bias voltage Vi output by the piezoelectric sensing output end when the piezoelectric sensing unit is not under pressure is the piezoelectric signal, and the piezoelectric signal conversion unit 12 converts the piezoelectric signal into a pressure-sensitive current signal and outputs the pressure-sensitive current signal to an input end of the current mirror 13.
In a specific implementation, the piezoelectric sensing unit 11 may be a piezoelectric sensor.
When the embodiment of the pressure detection circuit shown in fig. 1 of the present invention is in operation, in a pressure detection stage, the piezoelectric sensing unit 11 senses pressure, converts a pressure signal into a piezoelectric signal, and outputs the piezoelectric signal through the piezoelectric sensing output end; the piezoelectric signal conversion unit 12 converts the piezoelectric signal into a corresponding pressure-sensitive current signal, and outputs the pressure-sensitive current signal to an input end of the current mirror 13; the current mirror 13 converts the voltage-induced current signal input through the input end thereof into a charging current signal; the current mirror 13 outputs the charging current signal to a first end of the energy storage unit 14 through an output end thereof, so as to charge the energy storage unit 14 through the charging current signal; the output control unit 15 controls to disconnect the connection between the output terminal of the current mirror and the pressure detection output terminal Vou under the control of the corresponding row strobe line SEL;
at the moment of reading, the output control unit 15 controls to turn on the connection between the output of the current mirror 13 and the pressure detection output Vou under the control of the corresponding row strobe line SEL;
the reading time is the time which is arranged after the pressure detection stage and is close to the ending time of the pressure detection stage.
Specifically, the pressure signal conversion unit may include:
a grid electrode of the pressure signal conversion transistor is connected with the piezoelectric induction output end, a first pole of the pressure signal conversion transistor is connected with the input end of the current mirror, and a second pole of the pressure signal conversion transistor is connected with a second level input end; and the number of the first and second groups,
the bias voltage providing resistor is connected with a direct-current voltage end at a first end and connected with a grid electrode of the pressure signal conversion transistor at a second end;
the piezoelectric sensing unit may include a first plate, a second plate, and a piezoelectric material layer between the first plate and the second plate;
the first polar plate is connected with a third level input end, and the second polar plate is connected with the piezoelectric induction output end.
In specific implementation, the second level input end may be a ground end, or may also be a low level input end, but not limited thereto, and in actual operation, a voltage value of the second level input by the second level input end may be selected according to an actual situation;
in a specific implementation, the third level input terminal may be a ground terminal, or may also be a low level input terminal, but not limited thereto, and in an actual operation, a voltage value of the third level input by the third level input terminal may be selected according to an actual situation.
In a specific implementation, as shown in fig. 2, the pressure signal conversion unit 12 may include:
a pressure signal conversion transistor T1, having a gate connected to the piezoelectric sensing output terminal (i.e. the gate of T1 is connected to the piezoelectric node FD), a source connected to the input terminal of the current mirror (i.e. the source of T1 is connected to the input node a), and a drain connected to a ground terminal GND (in the embodiment shown in fig. 2, the second level input terminal is the ground terminal GND); and the number of the first and second groups,
an offset voltage providing resistor Z, a first terminal and an input DC voltage VDCThe second end of the direct current voltage end of the voltage signal conversion transistor T1 is connected with the grid electrode of the voltage signal conversion transistor T1;
the piezoelectric sensing unit 11 comprises a first polar plate, a second polar plate and a piezoelectric material layer positioned between the first polar plate and the second polar plate; in practical operation, the piezoelectric material layer may be made of piezoelectric ceramics, but is not limited thereto;
the first plate is connected to a ground GND (in the embodiment shown in fig. 2, the third level input terminal is the ground GND), and the second plate is connected to the piezoelectric sensing output terminal (that is, the second plate is connected to the piezoelectric node FD).
In the embodiment shown in fig. 2, T1 is exemplified as an n-type transistor, and in actual operation, T1 may also be a p-type transistor, and the type of T1 is not limited herein.
At an initial time T0, when the piezoelectric sensing unit 11 does not receive a pressure, the dc voltage terminal and the offset voltage providing resistor Z provide an offset voltage Vi to the gate of the pressure signal conversion transistor T1, so that T1 operates in the amplification region, at this time, the offset voltage Vi may make the initial drain-source current of T1 be i0, and at this time, the voltage of the output node B may be reset to the initial voltage V0 by the output control unit 15 (the output control unit 15 conducts the connection between the output node B and the pressure detection output terminal Vou under the control of the corresponding row select line SEL, so as to reset the voltage of the output node B to the initial voltage V0).
According to a specific embodiment, the current mirror may comprise an input transistor and an output transistor, wherein,
a gate of the input transistor is connected to a gate of the output transistor, a first pole of the input transistor and a first pole of the output transistor are both connected to a first voltage input terminal, and a second pole of the input transistor is connected to the gate of the input transistor; the second pole of the input transistor is the input end of the current mirror;
the second pole of the output transistor is the output end of the current mirror.
Specifically, the energy storage unit may include: a first end of the holding capacitor is connected with the output end of the current mirror, and a second end of the holding capacitor is connected with the first level input end;
the output control unit may include: and the grid of the output control transistor is connected with the corresponding row strobe line, the first pole of the output control transistor is connected with the output end of the current mirror, and the second pole of the output control transistor is connected with the pressure detection output end.
Preferably, the pressure detection circuit according to the embodiment of the present invention may further include a mirror transistor and a mirror resistor, wherein,
the first end of the mirror resistor is connected with the direct-current voltage end;
the grid electrode of the mirror image transistor is connected with the second end of the mirror image resistor, the first pole of the mirror image transistor is connected with the output end of the current mirror, and the second pole of the mirror image transistor is connected with the second level input end;
the resistance value of the mirror resistor is equal to that of the bias voltage supply resistor;
the width-to-length ratio of the mirror transistor is equal to that of the pressure signal conversion transistor;
the current value of the pressure-sensitive current signal input by the input end of the current mirror is equal to the current value of the charging current signal output by the output end of the current mirror;
the mirror image transistor and the pressure signal conversion transistor are both n-type transistors, or the mirror image transistor and the pressure signal conversion transistor are both p-type transistors.
On the basis of the pressure detection circuit shown in fig. 2, as shown in fig. 3, the pressure detection circuit according to a preferred embodiment of the present invention may further include a mirror transistor T5 and a mirror resistor ZJ, wherein,
the first end of the mirror resistor ZJ is connected with the direct-current voltage end; the DC voltage end is used for inputting DC voltage VDC；
The gate of the mirror transistor T5 is connected to the second terminal of the mirror resistor ZJ, the source of the mirror transistor T5 is connected to the output terminal of the current mirror 13, and the drain of the mirror transistor T5 is connected to the ground terminal GND;
the resistance value of the mirror resistor ZJ is equal to the resistance value of the bias voltage supply resistor Z;
the width-to-length ratio of the mirror transistor T5 is equal to the width-to-length ratio of the pressure signal conversion transistor T1;
the current value of the voltage-induced current signal input by the input end of the current mirror 13 is equal to the current value of the charging current signal output by the output end of the current mirror 13;
the mirroring transistor T5 and the pressure signal converting transistor T1 are both n-type transistors.
The preferred embodiment of the pressure detection circuit shown in fig. 3 of the present invention employs a mirror resistor ZJ and a mirror transistor T5, eliminates the offset current by adding T5 and ZJ, and directly charges the energy storage unit 14 by the varying current generated by the pressure sense, thereby simplifying the calculation.
Specifically, the pressure detection circuit according to the embodiment of the present invention may further include: and the pressure detection unit is connected with the pressure detection output end and used for detecting whether the piezoelectric sensing unit senses pressure according to the voltage signal output by the pressure detection output end and detecting the pressure value of the pressure according to the voltage signal when the piezoelectric sensing unit senses the pressure.
In practical operation, the pressure detection circuit according to the embodiment of the present invention may further include a pressure detection unit, where the pressure detection unit senses a pressure according to the voltage signal output by the pressure detection output terminal and calculates a pressure value of the pressure, and how to calculate the pressure value is described with reference to the following operation process of the first specific embodiment of the pressure detection circuit.
The pressure detection circuit of the present invention is illustrated by two specific embodiments.
As shown in fig. 4, the first embodiment of the pressure detection circuit according to the present invention includes a pressure detection output Vou, a piezoelectric sensing unit 11, a piezoelectric signal conversion unit 12, a current mirror 13, an energy storage unit 14, an output control unit 15, and a pressure detection unit (not shown in fig. 4), wherein,
the piezoelectric sensing unit 11 comprises a first polar plate, a second polar plate and a piezoelectric material layer positioned between the first polar plate and the second polar plate;
the first polar plate is connected with a ground end GND, and the second polar plate is connected with the piezoelectric induction output end; the piezoelectric induction output end is connected with a piezoelectric node FD;
the pressure signal conversion unit 12 includes:
a pressure signal conversion transistor T1, having a gate connected to the piezoelectric sensing output terminal (i.e. the gate of T1 is connected to the piezoelectric node FD), a source connected to the input terminal of the current mirror 13, and a drain connected to the ground GND; and the number of the first and second groups,
the bias voltage providing resistor Z has a first end connected with the direct-current voltage end and a second end connected with the grid electrode of the pressure signal conversion transistor T1; the DC voltage end is used for inputting DC voltage VDC；
The current mirror 13 includes an input transistor T2 and an output transistor T3, wherein,
the gate of the input transistor T2 is connected to the gate of the output transistor T3, the source of the input transistor T2 and the source of the output transistor are both connected to a high voltage input terminal to which a high voltage VDD is input, and the drain of the input transistor T2 is connected to the gate of the input transistor T2; the drain of the input transistor T2 is the input terminal of the current mirror 13;
the drain of the output transistor T3 is the output terminal of the current mirror 13;
the energy storage unit 14 includes: a holding capacitor CH having a first terminal connected to the drain of the output transistor T3 and a second terminal connected to the ground terminal GND;
the output control unit 15 includes: the output control transistor has a gate connected to the corresponding row strobe line SEL, a source connected to the drain of the output transistor T3, and a drain connected to the pressure detection output terminal Vou.
In the first embodiment of the pressure sensing circuit shown in fig. 4, the drain of the input transistor T2 is connected to the input node a, and the drain of the output transistor T3 is connected to the output node B.
In the first embodiment of the pressure detection circuit shown in fig. 4, T1, T2, T3, and T4 are all n-type transistors, but in actual operation, the transistors may be p-type transistors, and the types of transistors are not limited.
In the first embodiment of the pressure detection circuit shown in fig. 4, the current value of the pressure-sensitive current signal input by the input terminal of the current mirror 13 is equal to the current value of the charging current signal output by the output terminal of the current mirror 13, which is exemplified by the mirror ratio coefficient of the current mirror 13 being equal to 1, and in actual operation, the mirror ratio coefficient of the current mirror 13 may also be equal to other values.
In the first embodiment of the pressure detection circuit shown in fig. 4, the first level input terminal, the second level input terminal and the third level input terminal are all the ground terminal GND.
As shown in fig. 5, in operation of the first embodiment of the pressure sensing circuit of the present invention as shown in fig. 4,
at an initial time T0, when the piezoelectric sensing unit 11 does not receive pressure, the dc voltage source provides a bias voltage Vi to the gate of T1 through Z, so that T1 operates in the amplification region, the drain-source current of T1 is an initial drain-source current i0, the SEL controls T4 to be turned on, and the voltage VB at the output node B is reset to an initial voltage V0;
the pressure detection stage is entered into the pressure detection stage,
at the beginning of the pressure detection phase (i.e. from the initial time T0 to the first time T1), the piezoelectric sensing unit 11 is not under pressure, so the drain-source current of T1 is transmitted to the output node B through T2 and T3 included in the current mirror 13, and the holding capacitor CH is charged;
when the piezoelectric sensing unit 11 is stressed (the piezoelectric sensing unit 11 is stressed in a time period from a first time T1 to a second time T2), the voltage of the gate of the T1 starts to decrease, so that the drain-source current of the T1 changes, and at the first time T1, the drain-source current of the T1 is the first drain-source current i 1; from the first time T1 to the second time T2, the drain-source current of T1 gradually decreases to the inverted peak source current ipeak (i.e. the drain-source current of T1 when the gate voltage of T1 reaches the minimum value), then gradually increases from ipeak, and then at the second time T2, the drain-source current of T1 rises to the second drain-source current i2 (the current value of i2 is equal to the current value of i 0); the voltage VB of the output node gradually rises during this period (the period from the first time t1 to the second time t 2), at the first time t1, VB being equal to the first output voltage V1; at a second instant, VB equals the second output voltage V2;
in the time period from the second time T2 to the third time T3, the piezoelectric sensing unit 11 is not stressed, the drain-source current of T1 is almost unchanged, and VB gradually rises; at a third time T3, the drain-source current of T1 is a third drain-source current i3, VB is equal to the third output voltage; the third time T3 is a reading time, and the voltage of the output node B is read at the third time T3 (the reading operation can output the voltage of the output node B to Vou by turning on T4), so that it can be determined whether the piezoelectric sensing unit 11 is under pressure from the initial time T0 to the third time T3 (i.e., the reading time), and it cannot be determined that the piezoelectric sensing unit 11 is not pressed due to the fact that the reading time is not in the time period from the first time T1 to the second time T2.
Specifically, when the first embodiment of the pressure detecting unit of the present invention shown in fig. 4 is operated, the pressure detecting unit (not shown in fig. 4) may subtract (i0 × T0/C) from V3 to remove the voltage output from Vou from the dc signal, where T0 is a time during which a period from T0 to T3 lasts, and C is a capacitance value of CH, when no pressure is applied to the piezoelectric sensing unit 11 from T0 to T3, V3 to V0 should be equal to (i0 × T0/C), the pressure detecting unit compares V3 to V0 and (i0 × T0/C), and when an absolute value of a voltage difference between V3 to V0 and (i0 × T0/C) is greater than a predetermined difference, the pressure detecting unit determines that a pressure is applied to the piezoelectric sensing unit 11 during the period from T0 to T3.
The first embodiment of the pressure detection circuit according to the present invention can hold the piezoelectric signal, and therefore, the piezoelectric signal can be collected (read) after a certain time, that is, the pressure detection circuit is suitable for being used in a pressure sensing pixel array, and the piezoelectric signal of the entire array is held by using a row-by-row collection method without losing transient information. In addition, since the larger the pressing force of the piezoelectric sensing unit 11 is, the larger the voltage value of V3 can be obtained, the first embodiment of the pressure detection circuit of the present invention can be used for detecting the pressure value of the pressure roughly.
As shown in fig. 6, on the basis of the first embodiment of the pressure detection circuit shown in fig. 4, the second embodiment of the pressure detection circuit further includes a mirror transistor T5 and a mirror resistor ZJ, wherein,
the first end of the mirror resistor ZJ is connected with the direct-current voltage end; the DC voltage end is used for inputting DC voltage VDC；
The gate of the mirror transistor T5 is connected to the second terminal of the mirror resistor ZJ, the source of the mirror transistor T5 is connected to the output node B, and the drain of the mirror transistor T5 is connected to the ground GND;
the resistance value of the mirror resistor ZJ is equal to the resistance value of the bias voltage supply resistor Z;
the width-to-length ratio of the mirror transistor T5 is equal to the width-to-length ratio of the pressure signal conversion transistor T1;
the current value of the voltage-induced current signal input by the input end of the current mirror 13 is equal to the current value of the charging current signal output by the output end of the current mirror 13;
the mirroring transistor T5 and the pressure signal converting transistor T1 are both n-type transistors.
In the second embodiment of the pressure detection circuit shown in fig. 6, when the dc voltage source provides the bias voltage Vi to the gate of T5 through ZJ, so that the drain-source current of T5 is equal to i0, the voltage value transmitted to Vou through the turned-on T4 at the reading time is equal to V3 minus (i0 × T0/C), where T0 is the duration of the time period from T0 to T3, and C is the capacitance value of CH, so that the voltage output by Vou is the voltage after the dc signal is removed, and the calculation can be simplified.
The pressure detection method provided by the embodiment of the invention is applied to the pressure detection circuit, and comprises the following steps:
in a pressure detection stage, the piezoelectric sensing unit senses pressure, converts a pressure signal into a piezoelectric signal and outputs the piezoelectric signal through a piezoelectric sensing output end; the piezoelectric signal conversion unit converts the piezoelectric signal into a corresponding pressure-sensitive current signal and outputs the pressure-sensitive current signal to the input end of the current mirror; the current mirror converts a pressure-sensitive current signal input through an input end of the current mirror into a charging current signal; the current mirror outputs the charging current signal to a first end of the energy storage unit through an output end of the current mirror so as to charge the energy storage unit through the charging current signal; the output control unit controls the disconnection between the output end of the current mirror and the pressure detection output end under the control of the corresponding row strobe line;
at the moment of reading, the output control unit controls and conducts the connection between the output end of the current mirror and the pressure detection output end under the control of the corresponding row strobe line;
the reading time is the time which is arranged after the pressure detection stage and is close to the ending time of the pressure detection stage.
The pressure detection method of the embodiment of the invention also comprises the following steps: at an initial moment, the output control unit controls and conducts the connection between the output end of the current mirror and the pressure detection output end so as to reset the potential of the output end of the current mirror to an initial voltage;
the initial time is a time immediately before the pressure detection stage and immediately before the start time of the pressure detection stage.
Specifically, the pressure detection circuit further comprises a pressure detection unit; the pressure detection method further includes:
the pressure detection unit detects whether the piezoelectric sensing unit senses pressure according to the voltage signal output by the pressure detection output end at the reading moment, and detects the pressure value of the pressure according to the voltage signal when the piezoelectric sensing unit senses the pressure.
The pressure detection module comprises a plurality of rows of gate lines, a plurality of columns of reading lines and a plurality of rows and columns of pressure detection circuits arranged in an array;
the pressure detection circuit on the same row comprises an output control unit, the control end of which is connected with the gate line on the same row;
and the pressure detection output ends of the pressure detection circuits positioned in the same column are connected with the reading lines in the same column.
The display device provided by the embodiment of the invention comprises the pressure detection module.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (10)
1. A pressure detection circuit is characterized by comprising a pressure detection output end, a piezoelectric induction unit, a piezoelectric signal conversion unit, a current mirror, an energy storage unit and an output control unit, wherein,
the piezoelectric sensing unit is used for sensing pressure, converting a pressure signal into a piezoelectric signal and outputting the piezoelectric signal through a piezoelectric sensing output end;
the input end of the piezoelectric signal conversion unit is connected with the piezoelectric induction output end, the output end of the piezoelectric signal conversion unit is connected with the input end of the current mirror, and the piezoelectric signal conversion unit is used for converting the piezoelectric signal into a corresponding pressure-sensitive current signal and outputting the pressure-sensitive current signal through the output end;
the output end of the current mirror is connected with the first end of the energy storage unit, and the second end of the energy storage unit is connected with the first level input end;
the control end of the output control unit is connected with the corresponding row strobe line, and the output control unit is used for controlling the connection or disconnection between the output end of the current mirror and the pressure detection output end under the control of the corresponding row strobe line.
2. The pressure detection circuit according to claim 1, wherein the pressure signal conversion unit includes:
a grid electrode of the pressure signal conversion transistor is connected with the piezoelectric induction output end, a first pole of the pressure signal conversion transistor is connected with the input end of the current mirror, and a second pole of the pressure signal conversion transistor is connected with a second level input end; and the number of the first and second groups,
the bias voltage providing resistor is connected with a direct-current voltage end at a first end and connected with a grid electrode of the pressure signal conversion transistor at a second end;
the piezoelectric induction unit comprises a first polar plate, a second polar plate and a piezoelectric material layer positioned between the first polar plate and the second polar plate;
the first polar plate is connected with a third level input end, and the second polar plate is connected with the piezoelectric induction output end.
3. The pressure detection circuit of claim 1, wherein the current mirror includes an input transistor and an output transistor, wherein,
a gate of the input transistor is connected to a gate of the output transistor, a first pole of the input transistor and a first pole of the output transistor are both connected to a first voltage input terminal, and a second pole of the input transistor is connected to the gate of the input transistor; the second pole of the input transistor is the input end of the current mirror;
the second pole of the output transistor is the output end of the current mirror;
the energy storage unit includes: a first end of the holding capacitor is connected with the output end of the current mirror, and a second end of the holding capacitor is connected with the first level input end;
the output control unit includes: and the grid of the output control transistor is connected with the corresponding row strobe line, the first pole of the output control transistor is connected with the output end of the current mirror, and the second pole of the output control transistor is connected with the pressure detection output end.
4. The pressure sensing circuit of claim 2, further comprising a mirror transistor and a mirror resistor, wherein,
the first end of the mirror resistor is connected with the direct-current voltage end;
the grid electrode of the mirror image transistor is connected with the second end of the mirror image resistor, the first pole of the mirror image transistor is connected with the output end of the current mirror, and the second pole of the mirror image transistor is connected with the second level input end;
the resistance value of the mirror resistor is equal to that of the bias voltage supply resistor;
the width-to-length ratio of the mirror transistor is equal to that of the pressure signal conversion transistor;
the current value of the pressure-sensitive current signal input by the input end of the current mirror is equal to the current value of the charging current signal output by the output end of the current mirror;
the mirror image transistor and the pressure signal conversion transistor are both n-type transistors, or the mirror image transistor and the pressure signal conversion transistor are both p-type transistors.
5. The pressure detection circuit of any of claims 1-4, further comprising: and the pressure detection unit is connected with the pressure detection output end and used for detecting whether the piezoelectric sensing unit senses pressure according to the voltage signal output by the pressure detection output end and detecting the pressure value of the pressure according to the voltage signal when the piezoelectric sensing unit senses the pressure.
6. A pressure detection method applied to the pressure detection circuit according to any one of claims 1 to 5, the pressure detection method comprising:
in a pressure detection stage, the piezoelectric sensing unit senses pressure, converts a pressure signal into a piezoelectric signal and outputs the piezoelectric signal through a piezoelectric sensing output end; the piezoelectric signal conversion unit converts the piezoelectric signal into a corresponding pressure-sensitive current signal and outputs the pressure-sensitive current signal to the input end of the current mirror; the current mirror converts a pressure-sensitive current signal input through an input end of the current mirror into a charging current signal; the current mirror outputs the charging current signal to a first end of the energy storage unit through an output end of the current mirror so as to charge the energy storage unit through the charging current signal; the output control unit controls the disconnection between the output end of the current mirror and the pressure detection output end under the control of the corresponding row strobe line;
at the moment of reading, the output control unit controls and conducts the connection between the output end of the current mirror and the pressure detection output end under the control of the corresponding row strobe line;
the reading time is the time which is arranged after the pressure detection stage and is close to the ending time of the pressure detection stage.
7. The pressure detection method of claim 6, further comprising: at an initial moment, the output control unit controls and conducts the connection between the output end of the current mirror and the pressure detection output end so as to reset the potential of the output end of the current mirror to an initial voltage;
the initial time is a time immediately before the pressure detection stage and immediately before the start time of the pressure detection stage.
8. The pressure detection method according to claim 6 or 7, wherein the pressure detection circuit further comprises a pressure detection unit; the pressure detection method further includes:
the pressure detection unit detects whether the piezoelectric sensing unit senses pressure according to the voltage signal output by the pressure detection output end at the reading moment, and detects the pressure value of the pressure according to the voltage signal when the piezoelectric sensing unit senses the pressure.
9. A pressure detection module, comprising a plurality of rows of gate lines, a plurality of columns of read lines, and a plurality of rows and columns of the pressure detection circuit as claimed in any one of claims 1 to 5 arranged in an array;
the pressure detection circuit on the same row comprises an output control unit, the control end of which is connected with the gate line on the same row;
and the pressure detection output ends of the pressure detection circuits positioned in the same column are connected with the reading lines in the same column.
10. A display device comprising the pressure detection module of claim 9.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102483663A (en) * | 2009-08-27 | 2012-05-30 | 京瓷株式会社 | Input device |
| CN104281287A (en) * | 2013-07-09 | 2015-01-14 | 瑞鼎科技股份有限公司 | Touch control pen and operation method thereof |
| JP2017090276A (en) * | 2015-11-11 | 2017-05-25 | ローム株式会社 | Piezoelectric sensor, sensor system, and piezoelectric element |
| CN106782312A (en) * | 2017-03-08 | 2017-05-31 | 合肥鑫晟光电科技有限公司 | A kind of image element circuit and its driving method, display device |
| CN107330409A (en) * | 2017-07-03 | 2017-11-07 | 京东方科技集团股份有限公司 | A kind of current amplification circuit, finger print detection device and its control method |
| CN107340924A (en) * | 2017-07-14 | 2017-11-10 | 京东方科技集团股份有限公司 | Touch-control circuit, contact panel, display panel and display device |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105892757B (en) * | 2016-06-24 | 2019-02-22 | 京东方科技集团股份有限公司 | A kind of In-cell touch panel and display device |
| CN107526472B (en) * | 2017-08-29 | 2020-05-01 | 京东方科技集团股份有限公司 | Piezoelectric detection circuit, detection method thereof and display device |
-
2018
- 2018-02-26 CN CN201810161437.1A patent/CN108375431B/en not_active Expired - Fee Related
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102483663A (en) * | 2009-08-27 | 2012-05-30 | 京瓷株式会社 | Input device |
| CN104281287A (en) * | 2013-07-09 | 2015-01-14 | 瑞鼎科技股份有限公司 | Touch control pen and operation method thereof |
| JP2017090276A (en) * | 2015-11-11 | 2017-05-25 | ローム株式会社 | Piezoelectric sensor, sensor system, and piezoelectric element |
| CN106782312A (en) * | 2017-03-08 | 2017-05-31 | 合肥鑫晟光电科技有限公司 | A kind of image element circuit and its driving method, display device |
| CN107330409A (en) * | 2017-07-03 | 2017-11-07 | 京东方科技集团股份有限公司 | A kind of current amplification circuit, finger print detection device and its control method |
| CN107340924A (en) * | 2017-07-14 | 2017-11-10 | 京东方科技集团股份有限公司 | Touch-control circuit, contact panel, display panel and display device |
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