CN109308143A - A kind of capacitive sensing device and its sensor circuit - Google Patents
A kind of capacitive sensing device and its sensor circuit Download PDFInfo
- Publication number
- CN109308143A CN109308143A CN201710617285.7A CN201710617285A CN109308143A CN 109308143 A CN109308143 A CN 109308143A CN 201710617285 A CN201710617285 A CN 201710617285A CN 109308143 A CN109308143 A CN 109308143A
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- amplifier
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- induction plate
- sensing device
- capacitive sensing
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- 230000006698 induction Effects 0.000 claims abstract description 56
- 239000003990 capacitor Substances 0.000 claims abstract description 37
- 230000005611 electricity Effects 0.000 claims description 9
- 239000002184 metal Substances 0.000 claims description 3
- 230000003321 amplification Effects 0.000 description 3
- 238000003199 nucleic acid amplification method Methods 0.000 description 3
- 230000003071 parasitic effect Effects 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000012935 Averaging Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
Classifications
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
- G06F3/044—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by capacitive means
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G06V40/00—Recognition of biometric, human-related or animal-related patterns in image or video data
- G06V40/10—Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
- G06V40/12—Fingerprints or palmprints
- G06V40/13—Sensors therefor
- G06V40/1306—Sensors therefor non-optical, e.g. ultrasonic or capacitive sensing
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- Engineering & Computer Science (AREA)
- Theoretical Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Human Computer Interaction (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Multimedia (AREA)
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
- Electronic Switches (AREA)
Abstract
The invention discloses a kind of capacitive sensing device and its sensor circuit, the capacitive sensing device includes the dielectric layer of ecto-entad setting, driving induction plate, induction plate, offsets pole plate, feedback pole plate and amplifier.When human contact or pressing are on a certain pixel unit of capacitive sensing device, body capacitance C is formed between human body and groundb, driving inductance capacitance C is formed between human body and driving induction platedInductance capacitance Cs is formed between human body and induction plate, it is formed between induction plate and counteracting pole plate and offsets capacitor Cc, it feeds back and forms feedback capacity Cfb between pole plate and induction plate, the signal for acting on inductance capacitance Cs is obtained by sensor circuit, to identify the shape of contact surface between human body and capacitive sensing device.
Description
Technical field
The invention belongs to capacitance sensing technology field more particularly to a kind of capacitive sensing devices and its sensor circuit.
Background technique
The finger lines of people has depth difference, and convex place is known as " peak ", and recessed place is known as " paddy ".Capacitance type fingerprint sense
Answering device is usually to utilize " peak " and " paddy " the corresponding inductance capacitance for including of different sizes on fingerprint, under AC signal excitation
The amplitude of output signal also different principle, converts corresponding voltage signal for the different inductance capacitances of " peak " and " paddy ".
In the prior art generally using dual input amplifier realize voltage signal amplification, but this mode can introduce compared with
Big parasitic capacitance is to influence the accuracy measured, and power consumption is big, narrow bandwidth.
Summary of the invention
The embodiment of the invention provides a kind of capacitive sensing device and its sensor circuits, it is intended to solve in the prior art using double
Input amplifier realizes the amplification of voltage signal, can introduce biggish parasitic capacitance to influence the accuracy of measurement, and function
The problem of consumption is big, narrow bandwidth.
The first aspect of the embodiment of the present invention provides a kind of capacitive sensing device, is formed when for incuding with human contact
Capacitor, which is characterized in that capacitive sensing device includes the dielectric layer of ecto-entad setting, driving induction plate, induction plate, counteracting
Pole plate, feedback pole plate and amplifier.
Driving induction plate, induction plate and counteracting pole plate are set to the inside of dielectric layer, and driving induction plate is in grid
Shape drives and is equipped with adjacent induction plate in each position of leaving a blank of induction plate and offsets pole plate, induction plate it is interior
Side is equipped with feedback pole plate, and the inside for feeding back pole plate is equipped with amplifier.
In one embodiment, dielectric layer is insulating component.
In one embodiment, driving induction plate, induction plate, offsetting pole plate and feed back pole plate is metal component.
In one embodiment, amplifier is single ended input amplifier.
The second aspect of the embodiment of the present invention provides a kind of sensor circuit applied to capacitive sensing device as described above,
For being connected between external drive source and processor, which is characterized in that including drive module, body capacitance Cb, driving induction
Capacitor Cd, inductance capacitance CS, offset capacitor CC, feedback capacity Cfb, filter capacitor Cg, reset switch and amplifier.
The input terminal of drive module is the input terminal of sensor circuit and connects external drive source, and the first of drive module exports
Termination driving inductance capacitance CdFirst end, drive inductance capacitance CdSecond end and body capacitance CbFirst end and induced electricity
Hold CSFirst end connect altogether, body capacitance CbSecond end ground connection, the second output terminal of drive module connect offset capacitor CCFirst
End, inductance capacitance CSSecond end and offset capacitor CCSecond end, filter capacitor CgFirst end, feedback capacity CfbFirst
The input terminal at end, the first end of reset switch and amplifier connects altogether, filter capacitor CgSecond end ground connection, feedback capacity Cfb?
The output end of the second end and amplifier of two ends and reset switch connects the output end to form sensor circuit altogether and connects processor.
In one embodiment, inductance capacitance C is drivendTo drive in induction plate when human contact's capacitive sensing device
The capacitor of formation.
In one embodiment, inductance capacitance CSFor the electricity when human contact's capacitive sensing device, formed in induction plate
Hold.
In one embodiment, capacitor C is offsetCTo offset the electricity formed on pole plate when human contact's capacitive sensing device
Hold.
In one embodiment, feedback capacity CfbTo feed back the electricity formed on pole plate when human contact's capacitive sensing device
Hold.
In one embodiment, drive module includes driving amplifier, phase inverter and counteracting amplifier.
The input terminal of driving amplifier and the input terminal of phase inverter connect the input terminal to form drive module, driving amplifier altogether
Output end be drive module the first output end, phase inverter output termination offset amplifier input terminal, offset amplifier
Output end be drive module second output terminal.
Existing beneficial effect is the embodiment of the present invention compared with prior art: when human contact or pressing are in capacitive sensing
When on a certain pixel unit of device, body capacitance C is formed between human body and groundb, formed and driven between human body and driving induction plate
Dynamic inductance capacitance Cd, inductance capacitance Cs is formed between human body and induction plate, is formed and is offset between induction plate and counteracting pole plate
Capacitor Cc feeds back and forms feedback capacity Cfb between pole plate and induction plate, acts on inductance capacitance Cs by sensor circuit acquisition
Signal, to identify the shape of contact surface between human body and capacitive sensing device.
Detailed description of the invention
It to describe the technical solutions in the embodiments of the present invention more clearly, below will be to embodiment or description of the prior art
Needed in attached drawing be briefly described, it should be apparent that, the accompanying drawings in the following description is only of the invention some
Embodiment for those of ordinary skill in the art without any creative labor, can also be according to these
Attached drawing obtains other attached drawings.
Fig. 1 is the structural schematic diagram for the capacitive sensing device that one embodiment of the present of invention provides；
Fig. 2 is the cross-sectional view of Fig. 1；
Fig. 3 is the bottom view of layer where driving induction plate in Fig. 1, offsetting pole plate and induction plate；
Fig. 4 is the electrical block diagram for the sensor circuit that one embodiment of the present of invention provides.
Specific embodiment
In order to make the invention's purpose, features and advantages of the invention more obvious and easy to understand, below in conjunction with the present invention
Attached drawing in embodiment, technical scheme in the embodiment of the invention is clearly and completely described, it is clear that disclosed below
Embodiment be only a part of the embodiment of the present invention, and not all embodiment.Based on the embodiments of the present invention, this field
Those of ordinary skill's all other embodiment obtained without making creative work, belongs to protection of the present invention
Range.
Realization of the invention is described in detail below in conjunction with specific attached drawing:
Fig. 1 to Fig. 3 shows a kind of structure of capacitive sensing device provided by one embodiment of the invention, for the ease of saying
Bright, only parts related to embodiments of the present invention are shown, and details are as follows.
As shown in Figure 1 to Figure 3, a kind of capacitive sensing device provided by the embodiment of the present invention, for induction and human contact
When the capacitor that is formed, capacitive sensing device includes the dielectric layer 204 of ecto-entad setting, driving induction plate 205, induction plate
201, pole plate 202, feedback pole plate 203 and amplifier LNA are offset.
It drives induction plate 205, induction plate 201 and offsets the inside that pole plate 202 is set to dielectric layer 204, driving sense
It answers pole plate 205 in mesh shape, drives in each position of leaving a blank of induction plate 205 and be equipped with adjacent 201 He of induction plate
Pole plate 202 is offset, the inside of induction plate 201 is equipped with feedback pole plate 203, and the inside of feedback pole plate 203 is equipped with amplifier LNA.
In one embodiment, dielectric layer 204 is insulating component.
In one embodiment, induction plate 205, induction plate 201 are driven, pole plate 202 is offset and feeds back pole plate 203 is equal
For metal component.
In one embodiment, amplifier LNA is single ended input amplifier.
In the present embodiment, amplifier LNA can reduce parasitic capacitance using single ended input amplifier, reduce device power consumption,
Increase bandwidth.
Fig. 4 shows a kind of sensor circuit applied to capacitive sensing device as described above provided by one embodiment of the invention
Structure, for ease of description, only parts related to embodiments of the present invention are shown, and details are as follows.
As shown in figure 4, a kind of sensor circuit 100 applied to capacitive sensing device as above provided by the embodiment of the present invention,
For being connected between external drive source 200 and processor 300, including drive module 110, body capacitance Cb, driving induced electricity
Hold Cd, inductance capacitance CS, offset capacitor CC, feedback capacity Cfb, filter capacitor Cg, reset switch K1 and amplifier LNA.
The input terminal of drive module 110 is the input terminal of sensor circuit 100 and connects external drive source 200, drive module
110 the first output termination driving inductance capacitance CdFirst end, drive inductance capacitance CdSecond end and body capacitance Cb?
One end and inductance capacitance CSFirst end connect altogether, body capacitance CbSecond end ground connection, the second output terminal of drive module 110 connects
Offset capacitor CCFirst end, inductance capacitance CSSecond end and offset capacitor CCSecond end, filter capacitor CgFirst end,
Feedback capacity CfbFirst end, the first end of reset switch K1 and amplifier LNA input terminal connect altogether, filter capacitor CgSecond
End ground connection, feedback capacity CfbSecond end and the second end and the output end of amplifier LNA of reset switch K1 connect to form induction altogether
The output end of circuit 100 simultaneously connects processor 300.
In one embodiment, body capacitance CbThe capacitor formed between human body and ground.
In one embodiment, inductance capacitance C is drivendTo drive induction plate 205 when human contact's capacitive sensing device
The capacitor of upper formation.
In one embodiment, inductance capacitance CSTo be formed in induction plate 201 when human contact's capacitive sensing device
Capacitor.
In one embodiment, capacitor C is offsetCTo be formed on counteracting pole plate 202 when human contact's capacitive sensing device
Capacitor.
In one embodiment, feedback capacity CfbTo be formed on feedback pole plate 203 when human contact's capacitive sensing device
Capacitor.
In one embodiment, drive module 110 includes driving amplifier U1, phase inverter U2 and counteracting amplifier U3；
The input terminal of driving amplifier U1 and the input terminal of phase inverter U2 connect the input terminal to form drive module 110 altogether, drive
The output end of dynamic amplifier U1 is the first output end of drive module 110, and the output termination of phase inverter U2 offsets amplifier U3's
Input terminal, the output end for offsetting amplifier U3 is the second output terminal of drive module 110.
In the present embodiment, human body and driving induction plate 205, between induction plate 201 by the dielectric layer 204 of insulation every
From, when human contact or pressing on a certain pixel unit of capacitive sensing device when, between human body and ground formed body capacitance Cb,
Driving inductance capacitance C is formed between human body and driving induction plate 205d, inductance capacitance Cs is formed between human body and induction plate,
It is formed between induction plate 201 and counteracting pole plate 202 and offsets capacitor Cc, fed back and formed instead between pole plate 203 and induction plate 201
Feed holds Cfb.
Drive inductance capacitance CdThe voltage at both ends can play driving effect, drive inductance capacitance CdWith body capacitance CbIt will
The driving voltage of driving amplifier U1 output is divided, and the driving voltage after partial pressure acts on inductance capacitance Cs, thus real
Signal detection when showing human contact or pressing capacitive sensing device.The output voltage of external drive source 200 is taken by phase inverter U2
By offsetting the counteracting voltage of amplifier U3 output and the opposite in phase of driving voltage after anti-, to eliminate common mode interference.
By taking a concrete application scene as an example, capacitive sensing device can be used for detecting the fingerprint of finger.Peak in finger print
Inductance capacitance Cs corresponding with paddy is of different sizes.When finger touches the surface of capacitive sensing circuit, external drive source 200 is defeated
AC signal out is loaded into driving inductance capacitance C after overdriven amplifier U1 amplifies A1 timesdOn, amplified AC signal
Through driving inductance capacitance CdWith body capacitance CbInductance capacitance Cs is acted on after partial pressure.Meanwhile the friendship that external drive source 200 exports
Flow and offset amplifier U3 after the inverted device U2 reverse phase of signal again and amplify A2 times, reverse phase and amplified AC signal act on to
Electric eliminating holds Cc.The signal of the side inductance capacitance Cs and offset after the Signal averaging of the side capacitor Cc by single ended input amplifier LNA into
Row amplification output.
The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the invention, all in essence of the invention
Made any modifications, equivalent replacements, and improvements etc., should all be included in the protection scope of the present invention within mind and principle.
Claims (10)
1. a kind of capacitive sensing device, the capacitor for incuding with being formed when human contact, which is characterized in that the capacitive sensing device
Dielectric layer, driving induction plate, induction plate, counteracting pole plate, feedback pole plate and amplifier including ecto-entad setting；
The driving induction plate, the induction plate and the inside offset pole plate and be set to the dielectric layer, the drive
Dynamic induction plate is in mesh shape, is equipped with the adjacent induction plate in each position of leaving a blank of the driving induction plate
With the counteracting pole plate, the inside of the induction plate is equipped with the feedback pole plate, and the inside of the feedback pole plate is equipped with described
Amplifier.
2. capacitive sensing device according to claim 1, which is characterized in that the dielectric layer is insulating component.
3. capacitive sensing device according to claim 1, which is characterized in that the driving induction plate, the induction plate,
The counteracting pole plate and the feedback pole plate are metal component.
4. capacitive sensing device according to claim 1, which is characterized in that the amplifier is single ended input amplifier.
5. a kind of sensor circuit applied to capacitive sensing device as described in claim 1, for be connected to external drive source and
Between processor, which is characterized in that including drive module, body capacitance Cb, driving inductance capacitance Cd, inductance capacitance CS, offset electricity
Hold CC, feedback capacity Cfb, filter capacitor Cg, reset switch and the amplifier；
The input terminal of the drive module be the sensor circuit input terminal and connect the external drive source, the driving mould
First output of block terminates the driving inductance capacitance CdFirst end, the driving inductance capacitance CdSecond end and the people
Body capacitance CbFirst end and the inductance capacitance CSFirst end connect altogether, the body capacitance CbSecond end ground connection, the drive
The second output terminal of dynamic model block meets the counteracting capacitor CCFirst end, the inductance capacitance CSSecond end and counteractings it is electric
Hold CCSecond end, the filter capacitor CgFirst end, the feedback capacity CfbFirst end, the reset switch first
The input terminal of end and the amplifier connects altogether, the filter capacitor CgSecond end ground connection, the feedback capacity CfbSecond end
Connect output end and the connection to form the sensor circuit altogether with the second end of the reset switch and the output end of the amplifier
The processor.
6. sensor circuit according to claim 5, which is characterized in that the driving inductance capacitance CdFor when human contact institute
It is described to drive the capacitor formed in induction plate when stating capacitive sensing device.
7. sensor circuit according to claim 5, which is characterized in that the inductance capacitance CSFor the electricity described in the human contact
The capacitor formed when holding inductor, in the induction plate.
8. sensor circuit according to claim 5, which is characterized in that the counteracting capacitor CCFor the electricity described in the human contact
It is described to offset the capacitor formed on pole plate when holding inductor.
9. sensor circuit according to claim 5, which is characterized in that the feedback capacity CfbFor the electricity described in the human contact
It is described to feed back the capacitor formed on pole plate when holding inductor.
10. sensor circuit according to claim 5, which is characterized in that the drive module includes driving amplifier, reverse phase
Device and counteracting amplifier；
The input terminal of the input terminal of the driving amplifier and the phase inverter meets the input terminal to form the drive module, institute altogether
The output end for stating driving amplifier is the first output end of the drive module, and the output termination counteracting of the phase inverter is put
The input terminal of big device, the output end for offsetting amplifier are the second output terminal of the drive module.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710617285.7A CN109308143A (en) | 2017-07-26 | 2017-07-26 | A kind of capacitive sensing device and its sensor circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710617285.7A CN109308143A (en) | 2017-07-26 | 2017-07-26 | A kind of capacitive sensing device and its sensor circuit |
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| Publication Number | Publication Date |
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| CN109308143A true CN109308143A (en) | 2019-02-05 |
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| CN201710617285.7A Pending CN109308143A (en) | 2017-07-26 | 2017-07-26 | A kind of capacitive sensing device and its sensor circuit |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104217193A (en) * | 2014-03-20 | 2014-12-17 | 深圳市汇顶科技股份有限公司 | Capacitance fingerprint sensing circuit and sensor |
| CN104331202A (en) * | 2014-11-07 | 2015-02-04 | 深圳市汇顶科技股份有限公司 | Fingerprint detection circuit, sensor and touch screen |
| CN205665714U (en) * | 2016-05-12 | 2016-10-26 | 戴孟军 | Fingerprint sensor and use its smart machine |
| CN106980411A (en) * | 2017-04-28 | 2017-07-25 | 北京集创北方科技股份有限公司 | Induction installation and driving method |
| CN106980824A (en) * | 2015-07-27 | 2017-07-25 | 深圳市汇顶科技股份有限公司 | Fingerprint detection circuit and fingerprint identification system |
| CN207302016U (en) * | 2017-07-26 | 2018-05-01 | 深圳指芯智能科技有限公司 | A kind of capacitive sensing device and its sensor circuit |
-
2017
- 2017-07-26 CN CN201710617285.7A patent/CN109308143A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104217193A (en) * | 2014-03-20 | 2014-12-17 | 深圳市汇顶科技股份有限公司 | Capacitance fingerprint sensing circuit and sensor |
| CN104331202A (en) * | 2014-11-07 | 2015-02-04 | 深圳市汇顶科技股份有限公司 | Fingerprint detection circuit, sensor and touch screen |
| CN106980824A (en) * | 2015-07-27 | 2017-07-25 | 深圳市汇顶科技股份有限公司 | Fingerprint detection circuit and fingerprint identification system |
| CN205665714U (en) * | 2016-05-12 | 2016-10-26 | 戴孟军 | Fingerprint sensor and use its smart machine |
| CN106980411A (en) * | 2017-04-28 | 2017-07-25 | 北京集创北方科技股份有限公司 | Induction installation and driving method |
| CN207302016U (en) * | 2017-07-26 | 2018-05-01 | 深圳指芯智能科技有限公司 | A kind of capacitive sensing device and its sensor circuit |
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Application publication date: 20190205 |