CN105138207A - Sensing unit of capacitive sensor - Google Patents
Sensing unit of capacitive sensor Download PDFInfo
- Publication number
- CN105138207A CN105138207A CN201510612657.8A CN201510612657A CN105138207A CN 105138207 A CN105138207 A CN 105138207A CN 201510612657 A CN201510612657 A CN 201510612657A CN 105138207 A CN105138207 A CN 105138207A
- Authority
- CN
- China
- Prior art keywords
- electrode
- sensing
- signal
- transistor
- transmission electrode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 230000008859 change Effects 0.000 claims abstract description 40
- 230000005540 biological transmission Effects 0.000 claims description 256
- 239000000758 substrate Substances 0.000 claims description 21
- 238000009413 insulation Methods 0.000 description 22
- 238000010586 diagram Methods 0.000 description 21
- 230000011664 signaling Effects 0.000 description 14
- 238000000034 method Methods 0.000 description 9
- 230000008569 process Effects 0.000 description 9
- 239000010409 thin film Substances 0.000 description 7
- 230000007274 generation of a signal involved in cell-cell signaling Effects 0.000 description 6
- 239000010408 film Substances 0.000 description 5
- 229910044991 metal oxide Inorganic materials 0.000 description 5
- 150000004706 metal oxides Chemical class 0.000 description 5
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 5
- 229920005591 polysilicon Polymers 0.000 description 5
- 239000004065 semiconductor Substances 0.000 description 5
- 239000002800 charge carrier Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 3
- 230000003321 amplification Effects 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 230000008878 coupling Effects 0.000 description 3
- 238000010168 coupling process Methods 0.000 description 3
- 238000005859 coupling reaction Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000005611 electricity Effects 0.000 description 3
- 230000005669 field effect Effects 0.000 description 3
- 230000007246 mechanism Effects 0.000 description 3
- 238000003199 nucleic acid amplification method Methods 0.000 description 3
- 229910052710 silicon Inorganic materials 0.000 description 3
- 239000010703 silicon Substances 0.000 description 3
- 230000001737 promoting effect Effects 0.000 description 2
- OFIYHXOOOISSDN-UHFFFAOYSA-N tellanylidenegallium Chemical compound [Te]=[Ga] OFIYHXOOOISSDN-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 229910021417 amorphous silicon Inorganic materials 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 239000002041 carbon nanotube Substances 0.000 description 1
- 229910021393 carbon nanotube Inorganic materials 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000004069 differentiation Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000012163 sequencing technique Methods 0.000 description 1
Classifications
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Human Computer Interaction (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Multimedia (AREA)
- Theoretical Computer Science (AREA)
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
- Electronic Switches (AREA)
Abstract
The invention discloses a sensing unit of a capacitive sensor. The sensing unit comprises sensing electrodes and a sensing circuit. The sensing electrodes can be coupled to a target object in a capacitive mode and used for loading reference signals. The sensing circuit comprises differential pair transistors. The differential pair transistors are relevant to the sensing electrodes and used for responding to the reference signal change caused when the target object is close to or touches the sensing electrodes and correspondingly generating two different second alternating current signals. The two different second alternating current signals output by the sensing unit are stable.
Description
Technical field
The present invention relates to capacitive sensing technical field, particularly relate to a kind of sensing unit of capacitance type sensor.
Background technology
Along with the development of society, increasing electronic equipment (as: the various intelligent artifact such as mobile phone, panel computer, Wearable and Smart Home) generally all can arrange one or more sensing devices.Described sensing device comprises as the touch sensing device of sensing user touch operation, the biological information sensing device of sensing biological information of human body etc.At present, the capacitance-type sensing device that adopts such as biological information sensing device performs sense operation more.
Capacitance-type sensing device generally comprises capacitance type sensor and control circuit.Described capacitance type sensor comprises multiple sensing unit (sensor).The drive singal of described multiple sensing unit reception control circuit, and corresponding output sensing signal gives described control circuit, to obtain corresponding sensitive information when user touches described multiple sensing unit.
So, each sensing unit independent detection, exports single sensing signal respectively, and described single sensing signal (as: voltage and/or electricity) common intensity is more weak.In addition, the sensing signal such as voltage, electricity is subject to the impact of stray capacitance in capacitance-type sensing device in the process be transmitted, more unstable, thus causes the sensing of capacitance-type sensing device to there is out of true or occur the situation of erroneous judgement, affects Consumer's Experience.
Summary of the invention
In view of this, the invention provides the sensing unit of the more stable capacitance type sensor of a kind of output sensing signal.
The invention provides a kind of sensing unit of capacitance type sensor, comprising:
Sensing electrode, can be coupled to target object in a capacitive manner, for loading reference signal; With
Sensing circuit, comprises differential pair tube, is associated with described sensing electrode, for responding because of the close of target object or the change touching caused reference signal on sensing electrode, and the second AC signal that corresponding generation two is different.
Preferably, described two different the second AC signal are differential current signal.
Preferably, described differential pair tube comprises:
Third transistor, comprises the 3rd control electrode, the 5th transmission electrode and the 6th transmission electrode, and wherein, the 6th transmission electrode is for transmitting the second AC signal; 3rd control electrode and sensing electrode are two electrodes, and the 3rd control electrode connects sensing electrode, or the 3rd control electrode and sensing electrode are same electrode; 3rd control electrode is for loading the first reference signal; With
4th transistor, comprises the 4th control electrode, the 7th transmission electrode and the 8th transmission electrode, and wherein, the 4th control electrode is for loading the second reference signal; 7th transmission electrode and the 5th transmission electrode are used for being connected with a current source; 8th transmission electrode is for transmitting the second AC signal.
Preferably, described sensing circuit comprises the first switch element further, and the first switch element is connected between described differential pair tube and described current source, for controlling whether carry out current delivery between described differential pair tube and described current source.
Preferably, described sensing circuit comprises second switch unit further, and whether transmit the first reference signal and the second reference signal to described differential pair tube for controlling, wherein, the first reference signal is identical with the second reference signal.
Preferably, described capacitance type sensor comprises the first signal wire, secondary signal line, the 3rd signal wire, the first sweep trace and the second sweep trace, and described 7th transmission electrode is connected the first signal wire with the 5th transmission electrode by the first switch element; 6th transmission electrode is used for being connected with secondary signal line; 8th transmission electrode is used for being connected with the 3rd signal wire; Described first switch element comprises:
The first transistor, comprise the first control electrode, the first transmission electrode and the second transmission electrode, wherein, described first control electrode is connected with the first sweep trace, described first transmission electrode is used for being connected with the first signal wire, and described second transmission electrode is used for being connected with the 5th transmission electrode; With
Transistor seconds, described transistor seconds comprises the second control electrode, the 3rd transmission electrode and the 4th transmission electrode, and wherein, the second control electrode is used for being connected with the second sweep trace; 3rd transmission electrode is connected with the second transmission electrode; 4th transmission electrode is connected with the 5th transmission electrode.
Preferably, described capacitance type sensor comprises three scan line and reference signal line further, and described second switch unit comprises:
5th transistor, comprises the 5th control electrode, the 9th transmission electrode and the tenth transmission electrode, and wherein, the 5th control electrode is used for being connected with a three scan line; 9th transmission electrode is for connecting a reference signal line; Tenth transmission electrode connects the 3rd control electrode; Wherein, the 3rd control electrode is for receiving from the first reference signal on reference signal line by the 5th transistor; With
6th transistor, comprises the 6th control electrode, the 11 transmission electrode and the 12 transmission electrode, and wherein, the 6th control electrode is used for being connected with a three scan line; 11 transmission electrode is for connecting a reference signal line; 12 transmission electrode connects the 4th control electrode; Wherein, the 4th control electrode is for receiving from the second reference signal on reference signal line by the 6th transistor.
Preferably, described capacitance type sensor comprises the 4th sweep trace further, and described sensing unit comprises further:
7th transistor, comprises the 7th control electrode, the 13 transmission electrode and the 14 transmission electrode, and wherein, the 7th control electrode is for connecting one the 4th sweep trace; 13 transmission electrode connects the tenth transmission electrode; 14 transmission electrode connects the 3rd control electrode; 13 transmission electrode and the 14 transmission electrode short circuit; With
8th transistor, comprises the 8th control electrode, the 15 transmission electrode and the 16 transmission electrode, and wherein, the 8th control electrode is for connecting one the 4th sweep trace; 15 transmission electrode connects the 12 transmission electrode; 16 transmission electrode connects the 4th control electrode; 15 transmission electrode and the 16 transmission electrode short circuit.
Preferably, the 5th control electrode and the 6th control electrode short circuit be connected to same three scan line; 9th transmission electrode and the 11 transmission electrode short circuit are also connected to same reference signal line; 7th control electrode and the 8th control electrode short circuit and be connected to same 4th sweep trace.
Preferably, the 7th transistor is used for and the 5th transistor alternate conduction, and the 7th transistor of conducting compensates the voltage between the 3rd control electrode and the tenth transmission electrode when the 5th transistor cutoff; 8th transistor is used for and the 6th transistor alternate conduction, and the 8th transistor of conducting compensates the voltage between the 4th control electrode and the 12 transmission electrode when the 6th transistor cutoff.
Preferably, described capacitance type sensor comprises the substrate for carrying sensing unit further, when described sensing electrode and described 3rd control electrode are two electrodes, described sensing circuit is arranged between described sensing electrode and described substrate, and in the structure of described sensing circuit, contact hole is set, described sensing electrode is connected with described 3rd control electrode by described contact hole; When described sensing electrode and described 3rd control electrode are same electrode, described 3rd control electrode is arranged compared to the 5th transmission electrode and the contiguous described substrate of the 6th transmission electrode.
Preferably, described differential pair tube on sensing electrode because of target object close to or the variable quantity of reference signal caused by touching change and amplify, to produce the differential current signal of amplification.
Preferably, the sensing unit of described capacitance type sensor is the sensing unit of fingerprint sensor.
Because described sensing unit comprises described differential pair tube, described differential pair tube is for responding on sensing electrode because of the close of target object or the change touching caused reference signal, and corresponding two the second different AC signal that produce, described two different the second AC signal are differential signal, more stable, therefore, the sensing signal of described sensing unit output is more stable.
Although disclose multiple embodiment, comprise its change, by illustrate and describing the following detailed description of illustrative embodiment disclosed by the invention, other embodiments disclosed by the invention will be apparent to those skilled in the art.To recognize, the present invention openly can various apparent in amendment, all modifications all can not depart from the spirit and scope of the present invention.Correspondingly, accompanying drawing and detailed description should be regarded as illustrative in essence, instead of restrictive.
Accompanying drawing explanation
Describe its example embodiment in detail by referring to accompanying drawing, feature of the present invention and advantage will become more obvious.
Fig. 1 is the schematic diagram of the first embodiment of capacitance-type sensing device of the present invention.
Fig. 2 is the electrical block diagram of capacitance-type sensing device shown in Fig. 1.
The part circuit structure schematic diagram that Fig. 3 is capacitance type sensor shown in Fig. 2.
The part circuit structure schematic diagram that Fig. 4 is capacitance-type sensing device shown in Fig. 2.
The schematic diagram of other change embodiment that Fig. 5 and Fig. 6 is sensing circuit shown in Fig. 3.
Fig. 7 is the schematic diagram of capacitance type sensor shown in Fig. 1.
The third transistor of one sensing unit and the cross-sectional view of sensing electrode of capacitance type sensor are mainly shown in Fig. 8 to Figure 11.
Figure 12 is the working timing figure of the capacitance-type sensing device shown in Fig. 2.
The part block diagram that Figure 13 is capacitance type sensor shown in Fig. 1.
Figure 14 is the schematic diagram of the second embodiment of capacitance-type sensing device of the present invention.
Figure 15 is the electrical block diagram of two sensing units adjacent on a line direction shown in Figure 14.
Figure 16 is the part circuit structure schematic diagram of the capacitance-type sensing device of Figure 14.
The frame structure schematic diagram that Figure 17 is capacitance type sensor shown in Figure 14.
Embodiment
More fully example embodiment is described referring now to accompanying drawing.But example embodiment can be implemented in a variety of forms, and should not be understood to be limited to embodiment set forth herein; On the contrary, these embodiments are provided to make the present invention comprehensively with complete, and the design of example embodiment will be conveyed to those skilled in the art all sidedly.Conveniently or clear, the thickness of every layer shown in accompanying drawing and size may be exaggerated, omit or be schematically illustrated in and the quantity of related elements is schematically shown.In addition, the size of element not exclusively reflects actual size, and the quantity incomplete reaction actual quantity of related elements.Reference numeral identical in the drawings represents same or similar structure.
In addition, described feature, structure can be combined in one or more embodiment in any suitable manner.In the following description, provide many details thus provide fully understanding embodiments of the present invention.But one of ordinary skill in the art would recognize that, what do not have in described specific detail is one or more, or adopts other structure, constituent element etc., also can put into practice technical scheme of the present invention.In other cases, be not shown specifically or describe known features or operate to avoid fuzzy the present invention.
In describing the invention, it is to be understood that " multiple " comprise two and two or more, unless otherwise expressly limited specifically." connection " can be electrical connection, is mechanically connected, couples, directly connect and the numerous embodiments such as connection indirectly, except the following special instruction of non-invention, otherwise and is not particularly limited.In addition, words such as " first ", " second " that occur in each element title and signal name is not limit the sequencing that element or signal occur, but for convenience of element name, clearly distinguishes each element, makes to describe more succinct.
It should be noted that further: capacitance-type sensing device provided by the invention is applicable to biological information sensing device, especially fingerprint sensing device.So, the present invention is not limited to this, and the sensing device of described capacitance-type sensing device also other suitable type applicable, as touch sensing device.Described biological information sensing device is used for the predetermined biological information of sensed object object.Described target object, as the finger for user, also can be the other parts of user's body, as palm, toe, ear etc., even also can be the object of other suitable type, and be not limited to human body.Described predetermined biological information is as being fingerprint, palmmprint, ear line etc.
Described capacitance-type sensing device comprises capacitance type sensor (sensors) and control circuit.Described control circuit connects capacitance type sensor, performs sense operation for controlling described capacitance type sensor.
Preferably, described capacitance type sensor comprises sensing electrode and differential pair tube.Described sensing electrode can be coupled to target object in a capacitive manner, for loading reference signal.Described differential pair tube is associated with described sensing electrode, for responding because of the close of target object or the change touching caused reference signal on sensing electrode, and corresponding generation differential signal.
Described control circuit receives described differential signal, and obtains corresponding sensitive information according to described differential signal correspondence.Described sensitive information is as the predetermined biological information for target object.Similarly, according to differential signal, described control circuit also can know that target object is close or touch this sensitive information of capacitance-type sensing device.
The sensing signal being transferred to control circuit due to capacitance type sensor of the present invention is differential signal, described differential signal is stronger, and the impact of differential signal by the stray capacitance in capacitance-type sensing device in the process being transferred to control circuit is less, therefore, the sensitive information that described control circuit obtains according to differential signal is relatively accurate and can reduce erroneous judgement, thus can promote Consumer's Experience.
Preferably, described differential signal is differential current signal.Preferably, described capacitance type sensor comprises multiple sensing electrode and multiple differential pair tube.The differential signal that same differential pair tube produces is the second ac current signal of same width with same frequency and reversed-phase.In addition, described differential pair tube is used for being connected with a current source, and described current source is used for providing one first constant DC signal.Described two different the second ac current signal sums are equal with the first constant DC signal that described current source provides.
Described differential pair tube is associated with described sensing electrode, wherein, described differential pair tube or be two element with described sensing electrode, described differential pair tube is connected with described sensing electrode; Or described differential pair tube comprises described sensing electrode, that is, described sensing electrode is a part for differential pair tube.
Described differential pair tube comprises two-transistor, and described two-transistor comprises a third transistor, and described third transistor comprises the 3rd control electrode, the 5th transmission electrode and the 6th transmission electrode.When described differential pair tube and described sensing electrode are two element, described 3rd control electrode is connected with described sensing electrode; When described differential pair tube comprises described sensing electrode, described 3rd control electrode and described sensing electrode are same electrode.
When described differential pair tube and described sensing electrode are two element, described 3rd control electrode is directly connected with described sensing electrode; Or described 3rd control electrode is connected with described sensing electrode by a current limiting element.Preferably, described current limiting element comprises resistance.Correspondingly, described current limiting element can play the effect of anti-ESD, protection capacitance type sensor.
Described capacitance type sensor comprises multiple sensing unit (sensor).Each sensing unit comprises sensing electrode described in.In addition, preferably, each sensing unit also comprises differential pair tube described in, or adjacent sensing unit comprises the transistor in differential pair tube described in separately.
By selecting the transistor with suitable mutual conductance, when target object close to or touch-sensing electrode time, the variable quantity of transistor to reference signal of described differential pair tube is changed and amplifies, produce two the first different AC signal, and two different the first AC signal are superimposed on the second identical constant DC signal respectively, correspondingly produce described two different the second AC signal to control circuit.Wherein, described second constant DC signal is the half of the first constant DC signal.Correspondingly, described sensing signal is comparatively strong, and the sensing result that described control circuit obtains according to described sensing signal is more accurate.
For capacitance type sensor of the present invention: or each sensing unit exports single current signal as sensing signal; Or each sensing unit output difference sub-signal is as sensing signal; Or adjacent sensing unit output difference sub-signal is as sensing signal; Wherein, described differential signal is as being differential current signal, known in being described further below, and the differential signal that described sensing unit exports also can be differential voltage signal, so, and the preferred differential current signal of described differential signal; More preferably, the sensing signal that the transistor forming differential pair tube exports is amplifying signal; Correspondingly, the sensing precision with the capacitance-type sensing device of described capacitance type sensor is higher.
Be described below in conjunction with the various embodiments of accompanying drawing to the circuit structure of capacitance-type sensing device.
The circuit structure of capacitance-type sensing device
Refer to Fig. 1, Fig. 1 is the schematic diagram of the first embodiment of capacitance-type sensing device of the present invention.Described capacitance-type sensing device 1, for being applied in an electronic equipment (not shown), performs sense operation.Described electronic equipment is as being the various smart machines such as mobile phone, panel computer, TV, telechiric device, intelligent door lock, Wearable.Described capacitance-type sensing device 1 comprises control circuit 11 and capacitance type sensor 13.Described control circuit 11 is connected with described capacitance type sensor 13.Described control circuit 11 performs sense operation for control capacitance formula sensor 13, and described capacitance type sensor 13 exports corresponding sensing signal to described control circuit 11.Described control circuit 11 obtains corresponding sensitive information according to described sensing signal further.
Described capacitance type sensor 13 comprises substrate 130, multiple sensing unit 131 and ground wire 133.Described ground wire 133 and described multiple sensing unit 131 are arranged on the homonymy of described substrate 130, and described ground wire 133 is arranged around each sensing unit 131.It should be noted that, the quantity of the sensing unit 131 shown in Fig. 1 is only signal, and the quantity of the sensing unit 131 of actual product can be less than or more than the quantity shown in Fig. 1.
Described multiple sensing unit 131 is connected with described control circuit 11, and for performing sense operation, output sensing signal is to control circuit 11.
In the present embodiment, described ground wire 133, for connecting the modulation ground NGND of described electronic equipment, receives modulation signal.Described modulation signal comprises ground signalling and drive singal, and described drive singal is higher than described ground signalling.Described modulation signal is as comprising the periodic square wave signal that ground signalling and drive singal alternately change.Wherein, described ground signalling is as the ground signalling on the equipment ground for electronic equipment, and the ground signalling on described equipment ground is constant voltage signal, as being 0V (volt).
Described substrate 130 is as being semiconductor substrate etc.Described semiconductor substrate is as being silicon substrate etc.
In the present embodiment, described control circuit 11 is arranged on described substrate 130, and is arranged on the homonymy of described substrate 130 with described multiple sensing unit 131.Change ground, in other embodiments, described control circuit 11 is integrated in a control chip, and described control chip is pressed together on described substrate 130.
In the present embodiment, the arrangement in array of described multiple sensing unit 131, as matrix form arrangement.So, the present invention does not limit the concrete arrangement mode of described multiple sensing unit 131, and such as, in other embodiments, described multiple sensing unit 131 also can be Else Rule mode or non-regular arrangement.
Refer to Fig. 2, Fig. 2 is the electrical block diagram of capacitance-type sensing device 1 shown in Fig. 1.It should be noted that, in fig. 2, clear in order to illustrate, 4 sensing units 131 are only shown.Described sensing unit 131 comprises sensing electrode 14 and sensing circuit 15.Described sensing electrode 14 can be coupled to target object in a capacitive manner, for loading reference signal.Described sensing circuit 15 for according to sensing electrode 14 because of target object close to or touch the change of caused reference signal, and corresponding two the second different AC signal that produce, and export described two different the second AC signal to described control circuit 11.
In present embodiment, described two different the second AC signal are differential signal, and are differential current signal.Described two different the second AC signal are such as the predetermined biological informations calculating target object, and described predetermined biological information is as being fingerprint.So, in other embodiments, described two different the second AC signal also can be differential voltage signal.
Described sensing electrode 14 adopt in metal material, metal conductive oxide material, conducing composite material, grapheme material, carbon nano-tube material any one make.
In the present embodiment, the structure of described multiple sensing unit 131 is identical.So, in other embodiments, the structure of described multiple sensing unit 131 can be different, such as, and the shape of sensing electrode 14 and varying in size.
See also Fig. 3 and Fig. 4, the part circuit structure schematic diagram that Fig. 3 is capacitance type sensor 13 shown in Fig. 2.The part circuit structure schematic diagram that Fig. 4 is capacitance-type sensing device 1 shown in Fig. 2.Below describe for a sensing unit 131 and target object is described for finger F, the structure & working mechanism of other sensing unit 131 is similar, repeats no more.Described sensing circuit 15 according on sensing electrode 14 because of finger F close to or touch the change of caused reference signal, and corresponding output sensing signal.Finger F close to or touch-sensing electrode 14 time, the fingerprint ridge of finger F or fingerprint paddy and sensing electrode 14 form coupling capacitance Cf, and described coupling capacitance Cf is with being electrically connected to the equipment of earth ground or described electronic equipment by human body impedance Z.Preferably, described coupling capacitance Cf is electrically connected the equipment ground of described electronic equipment by human body impedance Z.Be generally the negative pole of the power supply of electronic equipment described equipment.Power supply is as being battery.
Described sensing circuit 15 comprises change-over circuit 151.Described change-over circuit 151 is for responding sensing electrode 14 because of the close of finger F or the change touching caused reference signal, and the second AC signal that corresponding generation two is different.
In the present embodiment, described change-over circuit 151 change sensing electrode 14 because of finger F close to or the variable quantity that touches caused reference signal be two the first different AC signal, and superpose on identical the second constant DC signal of described two different the first AC signal respectively to one, correspondingly produce described two different the second AC signal.Wherein, two different the first AC signal are differential current signal.
Preferably, described change-over circuit 151 comprises differential pair tube D.Described differential pair tube D responds sensing electrode 14 because of the close of finger F or the change touching caused reference signal, and correspondence produces two the second different AC signal.
Described differential pair tube D comprises third transistor T3 and the 4th transistor T4.Described third transistor T3 comprises the 3rd control electrode C3, the 5th transmission electrode S5 and the 6th transmission electrode S6.Described 6th transmission electrode S6 is for transmitting one second AC signal.In the present embodiment, described 3rd control electrode C3 and described sensing electrode 14 are two electrodes, and described 3rd control electrode C3 directly connects described sensing electrode 14.So, in other embodiments, see Fig. 5, described 3rd control electrode C3 also connects described sensing electrode 14 by current limiting element L, and described current limiting element L comprises resistance R, plays the effect of anti-ESD.In addition, described 3rd control electrode C3 and described sensing electrode 14 also can be same electrode.
Described 4th transistor T4 comprises the 4th control electrode C4, the 7th transmission electrode S7 and the 8th transmission electrode S8.Described 7th transmission electrode S7 connects described 5th transmission electrode S5.Described 7th transmission electrode S7 and described 5th transmission electrode S5 are further used for being connected with a current source 111.Described current source 111 is for providing the first constant DC signal, and described first constant DC signal is two times of the second constant DC signal, and the size as the first constant DC signal is I, then the size of the second constant DC signal is (I/2).Preferably, define a node N between described 7th transmission electrode S7 and described 5th transmission electrode S5, described differential pair tube D connects described current source 111 by described node N.Described 8th transmission electrode S8 is for transmitting another the second AC signal.
3rd control electrode C3 is for loading the first reference signal, and the 4th control electrode C4 is for loading the second reference signal.Correspondingly, when the 3rd control electrode C3 and described sensing electrode 14 are same electrode, or when the 3rd control electrode C3 directly connects described sensing electrode 14, the reference signal that described sensing electrode 14 loads also is the first reference signal.It should be noted that, when the 3rd control electrode C3 is connected with sensing electrode 14 by current limiting element L, the reference signal that described sensing electrode 14 loads is different from the first reference signal that described 3rd control electrode C3 loads.
Preferably, the first reference signal that described 3rd control electrode C3 receives is identical with the second reference signal that described 4th control electrode C4 receives, that is, described differential pair tube D receives common-mode signal input.So, the second reference signal that the first reference signal that described 3rd control electrode C3 receives receives with described 4th control electrode C4 also can differ certain difference, as 0.05V (volt), 0.1V (volt) etc., the first reference signal is still considered as identical with the second reference signal.Be activated at sensing unit 131 in the process performing sensing, described 3rd control electrode C3 and described 4th control electrode C4 are respectively used to that interval (as periodicity) is corresponding on schedule loads the first reference signal and the second reference signal at every turn.Defining the period that the 3rd control electrode C3 and described 4th control electrode C4 receives the first reference signal and the second reference signal is charge period, comprises the sensing period in the period often between adjacent two charge period.In the sensing period, the first reference signal is stopped and is transferred to the 3rd control electrode C3, and the second reference signal is stopped the described 4th control electrode C4 of transmission, and described sensing cell 131 performs sensing.
In the present embodiment, described first reference signal and the second reference signal are modulated voltage signal.
In the sensing period, all stray capacitance is there is due to the 3rd control electrode C3 and between the 4th control electrode C4 and ground wire 133, when do not have finger close to or touch-sensing electrode 14 time, described first reference signal keeps relatively constant with the signal on the relative described ground wire 133 of described second reference signal; When have finger close to or touch-sensing electrode 14 time, the signal on the relatively described ground wire 133 of described first reference signal changes, and signal on the relatively described ground wire 133 of described second reference signal keeps relatively constant.
Particularly, when pointing close or touch-sensing electrode 14, described third transistor T3 changes the variable quantity of the reference signal on sensing electrode 14 into the first AC signal i, and load described first AC signal i on one second constant DC signal, thus on the 6th transmission electrode S6 formation second AC signal (I/2)+i.Correspondingly, by the component properties of differential pair tube D, described 4th transistor T4 changes the variable quantity of the reference signal on sensing electrode 14 into the first AC signal (-i), and load described first AC signal (-i) on one second constant DC signal, thus on the 8th transmission electrode S8 formation second AC signal (I/2)-i.Described 2 second AC signal (I/2)+i, (I/2)-i sum are equal with the size I of described first constant DC signal.Also namely, described differential pair tube D responds the change of the first reference signal R1 and corresponding generation exports from second AC signal of current source 111 to the six transmission electrode S6 and the 8th transmission electrode S8.
It should be noted that, by selecting the differential pair tube D with suitable mutual conductance, described first AC signal can by amplification in various degree, and therefore, relative to the variable quantity of reference signal or the variable quantity of electricity, the first AC signal is stronger.Correspondingly, according to the first AC signal entrained in the second AC signal is next corresponding, described control circuit 11 knows that the information in fingerprint of finger is then more accurate.Especially for differential pair tube D, described control circuit 11 carries out additive operation to receive two different second AC signal, can obtain first AC signal of two times, further increase the intensity of signal.
Preferably, described sensing circuit 15 comprises the first switch element K1 further.Described first switch element K1 is connected between described node N and described current source 111, for controlling whether carry out current delivery between described differential pair tube D and described current source 111.
Described first switch element K1 comprises the first transistor T1.Described the first transistor T1 comprises the first control electrode C1, the first transmission electrode S1 and the second transmission electrode S2.Described first control electrode C1 to control between the first transmission electrode S1 and the second transmission electrode S2 whether conducting for responding one scan signal correspondence.First transmission electrode S1 is for connecting described current source 111.Second transmission electrode S2 is for connecting described node N.
Preferably, described first switch element K1 comprises transistor seconds T2 further.Described transistor seconds T2 comprises the second control electrode C2, the 3rd transmission electrode S3 and the 4th transmission electrode S4.Described second control electrode C2 to control between the 3rd transmission electrode S3 and the 4th transmission electrode S4 whether conducting for responding one scan signal correspondence.3rd transmission electrode S3 is for connecting the second transmission electrode S2.4th transmission electrode S4 is for connecting described node N.Transistor seconds T2 and the first transistor T1 forms secondary switch.In the present embodiment, which which form secondary switch to be more conducive to control circuit 11 and to control or sensing unit 131 flexibly and be activated, in addition, after also can illustrate, the position of sensing unit 131 can be determined according to position relationship between the sweep trace be connected with described secondary switch.Change ground, in other embodiments, described first switch element K1 also can only comprise the first transistor T1.Further, described first switch element K1 also non-limitingly comprises the first transistor T1 and transistor seconds T2, also can comprise the on-off element of other suitable type.Further, described first switch element K1 also can be arranged in control circuit 11, but not in sensing unit 131, even, described first switch element K1 also can be omitted, and accordingly, arranges the first similar switch element K1 and be also fine between sensing electrode 14 and control circuit 11.
More preferably, described sensing circuit 15 comprises second switch unit K2 further.Described second switch unit K2 is used for controlling whether transmit the first reference signal and whether transmits the second reference signal to the 4th control electrode C4 to the 3rd control electrode C3 and control.Because differential pair tube D is associated with sensing electrode 14, therefore, the second control module K2 correspondence controls whether transmission of reference signals is to described sensing electrode 14.
Preferably, described second switch unit K2 comprises the 5th transistor T5 and the 6th transistor T6.
Described 5th transistor T5 comprises the 5th control electrode C5, the 9th transmission electrode S9 and the tenth transmission electrode S10.Wherein, the 5th control electrode C5 corresponding controls the 9th transmission electrode S9 and the tenth transmission electrode S10 whether conducting for responding one scan signal.9th transmission electrode S9 is for receiving the first reference signal.Tenth transmission electrode S10 connects the 3rd control electrode C3.
Described 6th transistor T6 comprises the 6th control electrode C6, the 11 transmission electrode S11 and the 12 transmission electrode S12.Wherein, the 6th control electrode C6 corresponding controls the 11 transmission electrode S11 and the 12 transmission electrode S12 whether conducting for responding one scan signal.11 transmission electrode is for receiving the second reference signal.12 transmission electrode S12 connects the 4th control electrode C4.
Change ground, in other embodiments, described second switch unit K2 also can be arranged in control circuit 11, but not in sensing unit 131.In addition, second switch unit K2 also non-limitingly comprises the 5th transistor T5 and the 6th transistor T6, also can be the on-off element comprising other suitable type.
More preferably, described sensing circuit 15 comprises the first compensating unit M1 and the second compensating unit M2 further.Described first compensating unit M1 is arranged between the tenth transmission electrode S10 and the 3rd control electrode C3, for compensating voltage when the 5th transistor T5 closes between the tenth transmission electrode S10 and the 3rd control electrode C3.Described second compensating unit M2 is arranged between the 12 transmission electrode S12 and the 4th control electrode C4, for compensating voltage when the 6th transistor T6 closes between the 12 transmission electrode S12 and the 4th control electrode C4.
Preferably, described first compensating unit M1 comprises the 7th transistor T7.Described 7th transistor T7 comprises the 7th control electrode C7, the 13 transmission electrode S13 and the 14 transmission electrode S14.Wherein, the 7th control electrode C7 controls the 13 transmission electrode S13 and the 14 transmission electrode S14 whether conducting for responding one scan signal.13 transmission electrode S13 connects the tenth transmission electrode S10.14 transmission electrode S14 connects the 3rd control electrode C3.13 transmission electrode S13 and the 14 transmission electrode S14 short circuit.
Described second compensating unit M2 comprises the 8th transistor T8.Described 8th transistor T8 comprises the 8th control electrode C8, the 15 transmission electrode S15 and the 16 transmission electrode S16.Wherein, the 8th control electrode C8 controls the 15 transmission electrode S15 and the 16 transmission electrode S16 whether conducting for responding one scan signal.15 transmission electrode S15 connects the 12 transmission electrode S12.16 transmission electrode S16 connects the 4th control electrode C4.15 transmission electrode S15 and the 16 transmission electrode S16 short circuit.
7th transistor T7 is used for and the 5th transistor T5 alternate conduction, and the 7th transistor T7 of conducting compensates the voltage between the 3rd control electrode C3 and the tenth transmission electrode S10 when the 5th transistor T5 ends; 8th transistor T8 is used for and the 6th transistor T6 alternate conduction, and the 8th transistor T8 of conducting compensates the voltage between the 4th control electrode C4 and the 12 transmission electrode S12 when the 6th transistor T6 ends.
It should be noted that, whether 7th transistor T7 and the 8th transistor T8 conducting to be described herein, refer to the 7th control electrode C7 and the 8th control electrode C8 responding scanning signal and correspondingly control the 7th transistor T7 and the 8th transistor T8 conducting respectively respectively, but not the 13 transmission electrode S13 of the 7th transistor T7 and the 14 transmission electrode S14 short circuit and conducting between the 13 transmission electrode S13 and the 14 transmission electrode S14, the 15 transmission electrode S15 of non-8th transistor T8 and the 16 transmission electrode S16 short circuit and conducting between the 15 transmission electrode S15 and the 16 transmission electrode S16.
Change ground, in other embodiments, described first compensating unit M1 and the second compensating unit M2 can be omitted.In addition, described first compensating unit M1 and the second compensating unit M2 also non-limitingly comprises the 7th transistor T7 and the 8th transistor T8 respectively, also can comprise the on-off element of other suitable type.
In order to avoid leakage current, for the part or all of transistor in sensing circuit 15, for the first transistor T1, the transistor be in series with each transistor can be comprised further, as shown in Figure 6.
In described sensing circuit 15 first to the 8th transistor T1 ~ T8 adopts any one or combinations several arbitrarily in thin film transistor (TFT), bipolarity triode and metal oxide semiconductor field effect tube.
Described thin film transistor (TFT) comprises the combination of any one or two kinds in N-type TFT, P-type TFT.
Described thin film transistor (TFT) comprises any one or combinations several arbitrarily in amorphous silicon film transistor, low-temperature polysilicon film transistor, high temperature polysilicon silicon thin film transistor, metal oxide thin-film transistor.
When the transistor in sensing circuit 15 adopts thin film transistor (TFT), the grid of described thin film transistor (TFT) is used as control electrode, and source electrode and drain electrode are used separately as transmission electrode; When the transistor in sensing circuit 15 adopts bipolarity triode, the base stage of described bipolarity triode is used as control electrode, and collector and emitter are used separately as transmission electrode; When the transistor in sensing circuit 15 adopts metal oxide semiconductor field effect tube, the grid of described metal oxide semiconductor field effect tube is used as control electrode, and source electrode and drain electrode are used separately as transmission electrode.
Please consult Fig. 2 and Fig. 3 in the lump again, described capacitance type sensor 13 comprises multiple sweep trace group G1, multiple signal wire group G2 and many reference signal line R further.Wherein, described sweep trace group G1 is for transmitting scanning-line signal to described multiple sensing unit 131.Described signal wire group G2 is used for transmission current signal between described multiple sensing unit 131 and described control circuit 11.Described many reference signal line R are for transmitting the first reference signal and the second reference signal to described multiple sensing unit 131.
One signal wire group G2 connects at least two sensing units 131.Scan line group G1 connects at least two sensing units 131.Preferably, in the present embodiment, each signal wire group G2 connects a row sensing unit 131.Different lines sensing unit 131 connects unlike signal line-group group G2.One signal wire group G2 is set between adjacent two row sensing units 131.
Described signal wire group G2 comprises the first signal wire G21, secondary signal line G22 and the 3rd signal wire G23.For each signal wire group G2: described first signal wire G21, secondary signal line G22 and the 3rd signal wire G23 extend along column direction, and described first signal wire G21, secondary signal line G22 and the 3rd signal wire G23 arrange in the row direction successively.Further, the first transmission electrode S1 of the first transistor T1 of the sensing unit 131 of same row connects same first signal wire G21.The 6th transmission electrode S6 of the third transistor T3 of the sensing unit 131 of same row connects same secondary signal line G22.8th transmission electrode S8 of the 4th transistor of the sensing unit 131 of same row connects same 3rd signal wire G23.Described first signal wire G21 is further used for being connected with current source 111, transmits described first constant DC signal.Described secondary signal line G22 and described 3rd signal wire G23 are further used for being connected with a treatment circuit 113.Described secondary signal line G22 and described 3rd signal G23 parallel transmission current signal between described sensing unit 131 and described treatment circuit 113.When have finger close to or touch-sensing electrode 14 and cause the change of reference signal time, described secondary signal line G22 and described 3rd signal G23 parallel transmission second AC signal between described sensing unit 131 and described treatment circuit 113; When do not have finger close to or touch-sensing electrode 14 time, described secondary signal line G22 and described 3rd signal G23 parallel transmission second constant DC signal between described sensing unit 131 and described treatment circuit 113.
Described sweep trace group G1 comprises the first sweep trace G11, the second sweep trace G12, three scan line G13 and the 4th sweep trace G14.First sweep trace G11 and the second sweep trace G12 insulate cross arrangement.In the present embodiment, described second sweep trace G12, three scan line G13 and the 4th sweep trace G14 extend all in the row direction, and described first sweep trace G11 extends along column direction.Particularly, the first control electrode C1 of the first transistor T1 of the sensing unit 131 of same row connects same first sweep trace G11.The second control electrode C2 with the transistor seconds T2 of the sensing unit 131 of a line connects same second sweep trace G12.The 5th control electrode C5 with the 5th transistor T5 of the sensing unit 131 of a line connects same three scan line G13.The 7th control electrode C7 with the 7th transistor T7 of the sensing unit 131 of a line connects same 4th sweep trace G14.The 8th control electrode C8 with the 8th transistor T8 of the sensing unit 131 of a line connects same 4th sweep trace G14.
Preferably, same three scan line G13 is connected to the 5th control electrode C5 of the 5th transistor T5 of the sensing unit 131 of a line and the 6th control electrode C6 short circuit of the 6th transistor T6.Be connected to same 4th sweep trace G14 with the 7th control electrode C7 of the 7th transistor T7 of the sensing unit 131 of a line and the 8th control electrode C8 short circuit of the 8th transistor T8.
Described first sweep trace G11, the second sweep trace G12, three scan line G13 are connected with scan driving circuit 115 further with the 4th sweep trace G14, receive the sweep signal from described scan drive circuit 115.
Change ground, in other embodiments, the first control electrode C1 with the first transistor T1 of the sensing unit 131 of a line connects the second sweep trace G12, and the second control electrode C2 of the transistor seconds T2 of the sensing unit 131 of same row connects the first sweep trace G11.Or, the location swap of the first sweep trace G11 and the second sweep trace G12, the first control electrode C1 with the first transistor T1 of the sensing unit 131 of a line connects the first sweep trace G11, and the second control electrode C2 of the transistor seconds T2 of the sensing unit 131 of same row connects the second sweep trace G12.
Because the first sweep trace G11 and the second sweep trace G12 insulate arranged in a crossed manner, therefore, according to the position relationship of the first sweep trace G11 and the second sweep trace G12, described control circuit 11 can know the position of each sensing unit 131.In addition, by arranging secondary switch, described control circuit 11 is also conducive to carrying out blocked scan to described multiple sensing unit 131.
Described many reference signal line R extend in the row direction.Described 9th transmission electrode S9 connects a reference signal line R.Described tenth transmission electrode S10 connects a reference signal line R.Preferably, same reference signal line R is connected to the tenth transmission electrode S10 phase short circuit with the 9th transmission electrode S9 of a line sensing unit 131, correspondingly, the first reference signal of the 3rd control electrode C3 reception is identical with the second reference signal that the 4th control electrode C4 receives.Relatively, when the 9th transmission electrode S9 of same a line sensing unit 131 connects different reference signal line R from the tenth transmission electrode S10, the first reference signal that 3rd control electrode C3 receives can be selected slightly different from the second reference signal that the 4th control electrode C4 receives, but the two is still considered as identical.Described many reference signal line R are further used for being connected with a reference signal generation circuit 117, receive the first reference signal from described reference signal generation circuit 117 and the second reference signal.
In the present embodiment, the second sweep trace G12, three scan line G13 and the 4th sweep trace G14 and reference signal line R in scan line group G1 is connected with the sensing unit 131 of a line.The second sweep trace G12, three scan line G13 and the 4th sweep trace G14 and reference signal line R in scan line group G1 is set between adjacent two row sensing units 131.
Refer to Fig. 7, Fig. 7 touches the schematic diagram of capacitance type sensor 13 shown in Fig. 1 for finger F.Please consult Fig. 1 and Fig. 2 in the lump, described sensing electrode 14 is arranged on than the position of described sensing circuit 15 closer to finger F simultaneously.In the present embodiment, described sensing circuit 15 is arranged between described sensing electrode 14 and described substrate 130, and contact hole (see following) is set in the structure of described sensing circuit 15, described sensing electrode 15 is connected with described 3rd control electrode C3 by described contact hole.Preferably, described sensing electrode 14 matches with ground wire 133 and covers sensing circuit 15, sweep trace group G1, reference signal line R and signal wire group G2 substantially completely, thus avoid when target object touch sensing circuit 15, sweep trace group G1, reference signal line R or signal wire group G2 time and cause the interference to sensing signal.In addition, the sensing electrode 14 of described each sensing unit 131 is preferably coplanar with layer.
Refer to Fig. 8 to Figure 11, the third transistor T3 of a sensing unit 131 and the cross-sectional view of sensing electrode 14 of capacitance type sensor 13 are mainly shown in Fig. 8 to Figure 11.Wherein, the third transistor T3 shown in Fig. 8 is low-temperature polysilicon film transistor.Described low-temperature polysilicon film transistor is single top-gate thin-film transistors.Described sensing circuit 15 is included on substrate 130 and forms the first insulation course 141, be formed in the active channel 142 and 143 on the first insulation course 141, source electrode 144 and drain electrode 145, be formed in the second insulation course 146 in active channel 142 and 143, source electrode 144 and drain electrode 145, be formed in the grid 147 on the second insulation course 146, be formed in the 3rd insulation course 148 on grid 147, run through the 3rd insulation course 148 until contact hole (sign) above grid 147, and be formed in the sensing electrode 14 above described 3rd insulation course 148.Described sensing electrode 14 is connected with described grid 147 by described contact hole.Wherein, third transistor T3 comprises active channel 142 and 143, source electrode 144, drain electrode the 145, second insulation course 146 and grid 147.
Third transistor T3 shown in Fig. 9 is bottom gate thin film transistor.Described sensing circuit 15 is included on substrate 130 and forms the first insulation course 141, be formed in the grid 147 on the first insulation course 141 and going between L of being connected with grid 147, be formed in the second insulation course 146 on grid 147 and the first insulation course 141, be formed in the active layer 149 on the second insulation course 146, be formed in source electrode 144 and the drain electrode 145 of active layer 149 both sides, with be formed in source electrode 144, three insulation course 148 of drain electrode 145 and second on insulation course 146, run through the contact hole of the 3rd insulation course 148 and the second insulation course 146, with the sensing electrode 14 be formed in above the 3rd insulation course 148.Wherein, described lead-in wire L extends to the position of described contact hole from the side of grid 147, described sensing electrode 14 connects described grid 147 by described contact hole.Described third transistor T3 comprises grid 147, second insulation course 146, active layer 149, source electrode 144 and drain electrode 145.Described active layer 149 is as being silicon island layer or metal oxide layer (IGZO).Described lead-in wire L is identical with the material of described grid 147, and itself and described grid 147 are structure as a whole.
Third transistor T3 shown in Figure 10 is inverted bottom gate thin film transistor.The grid of third transistor T3 is used as sensing electrode 14 further.As long as the structure shown in Fig. 9 is inverted, opposite side relative with the side arranging sensing unit 131 on substrate 130 is formed screen layer 40, cover the region except grid 23, and without the need to forming contact hole on the second insulation course 146 and the 3rd insulation course 148, without the need to forming lead-in wire L.Change ground, except opposite side relative with the side arranging sensing unit 131 on substrate 130 forms screen layer 40, cover the mode in the region except grid 23, the surrounding edge of grid 23 also can be selected to extend cover sensing circuit 15.Visible, when described sensing electrode 14 is same electrode with described 3rd control electrode C3, described 3rd control electrode C3 is arranged compared to the contiguous described substrate 130 of the 5th transmission electrode S5 and the 6th transmission electrode S6.
Third transistor T3 shown in Figure 11 is Double Tops grid low-temperature polysilicon film transistors.Similar with the sensing unit 131 shown in Fig. 8, the insulation course 148 on a grid 147 of third transistor T3 forms contact hole, sensing electrode 14 is connected with grid 147.Herein, the structure for third transistor T3 repeats no more.
As shown in the above, described capacitance type sensor 13 respond sensing electrode 14 because of target object close to or touch the change of caused reference signal and the corresponding differential current signal that produces, and provide differential current signal to control circuit 11, therefore, the sensing signal that exports of capacitance type sensor 13 of the present invention is comparatively strong and stability is higher.
Change ground, in other embodiments, at the 6th transmission electrode S6 and a resistance that the 8th transmission electrode S8 connects respectively, and draw two signal line respectively between differential pair tube D and each resistance, thus the corresponding differential voltage signal that gathers also is fine as sensing signal.
Referring again to Fig. 1 to Fig. 3, the circuit structure of capacitance-type sensing device 1 is described as follows.
Preferably, described control circuit 11 comprises an earth terminal 110, described current source 111, described treatment circuit 113, described scan drive circuit 115, described reference signal generation circuit 117 and sequential control circuit 119.Described sequential control circuit 119 is at least connected with described scan drive circuit 115, exports the sequential of each sweep signal for controlling described scan drive circuit 115.
In the present embodiment, described earth terminal 110, for connecting the modulation ground NGND of described electronic equipment, receives described modulation signal.Described earth terminal 110 and ground wire 133 transmit described modulation signal, thus, ground signalling is in compared to described modulation signal, when described modulation signal is in drive singal, the driving intensity that described control circuit 11 is transferred to the signal of capacitance type sensor 13 uprises, when being fingerprint sensing device for capacitance-type sensing device 1, and then more easily can sense fingerprint image.
So, in other embodiments, described earth terminal 110 and described ground wire 133 are all for being connected the equipment ground of described electronic equipment, and receive the ground signalling from equipment ground, described ground signalling is constant voltage signal.Correspondingly, described first reference signal and described second reference signal are constant voltage signal.
Described current source 111 is connected with the first signal wire G21, for providing described first constant DC signal.
Described reference signal generation circuit 117 is connected with described many reference signal line R, for providing described first reference signal and described second reference signal.
Described scan drive circuit 115 is connected with described each sweep trace group G1, for providing sweep signal to each article of the first sweep trace G11, each article of the second sweep trace G12, each article of three scan line G13 and each article of the 4th sweep trace G14.
Described treatment circuit 113 and secondary signal line G22 and the 3rd signal wire G23 parallel join, for receiving the sensing signal exported from described multiple sensing unit 131, after described sensing signal is changed and amplifying process, then calculate the associated sensed information of target object according to the sensing signal after process.
Particularly, when sensing signal is the second AC signal and is current signal, described treatment circuit 113 changes the second AC signal into corresponding ac voltage signal, and the ac voltage signal after conversion is amplified, the associated sensed information of target object is calculated according to the ac voltage signal amplified; Or described treatment circuit 113 amplifies the second AC signal received, and the second AC signal changed after amplification is corresponding ac voltage signal, calculates the associated sensed information of target object according to the ac voltage signal amplified.Described treatment circuit 113 carries out subtraction to through conversion and the ac voltage signal after amplifying further, and knows the associated sensed information of target object according to the signal obtained after computing.
Due to for for fingerprint sensing device, described sensing unit 131 is more, single pass a line sensing unit 131 needs more treatment circuit 113 and current source 111, therefore, for the capacitance-type sensing device 1 of such as fingerprint sensing type of device, inventor finds that the mode of employing time-sharing multiplex treatment circuit circuit 113 and current source 111 can be relatively good, correspondingly, described control circuit 11 comprises the 3rd switch element K3 (see Fig. 2) further, described 3rd switch-linear hybrid is in current source 111, between treatment circuit 113 and described multiple sensing unit 131, for switching described treatment circuit 113, connection between current source 111 and sensing unit 131.So, adopt secondary switch and in conjunction with the first sweep trace G11, connection between the second sweep trace G12 and sensing unit 21 and arrange relation, described control circuit 11 can be conducive to blocked scan is carried out to described capacitance type sensor 13.Correspondingly, e.g., a current source 111 is set without the need to each row sensing unit 131 corresponding, is switched by the control of the 3rd switch element K3, with a line sensing unit 131 time-sharing multiplex described in current source 111.Similarly, treatment circuit 113 is suitable for too.Wherein, the 3rd switch element K3 comprises multiple gauge tap K31.Described 3rd switch element K3 is connected with sequential control circuit 119, and whether sequential control circuit 119 for controlling the closedown of the multiple gauge tap K31 in the 3rd switch element K3.So, in other embodiments, described control circuit 11 can comprise a control module further and works to replace sequential control circuit 119 to control the 3rd switch element K3.
Certainly, if treatment circuit 113 and current source 111 more, or, the negligible amounts of sensing unit 131, without the need to the sensing unit 131 points of every a line at least twice sweep time, described first switch element K1 comprises a transistor, described sweep trace group G1 comprises one in the first sweep trace G11 and the second sweep trace G12.
See also Figure 12, Figure 12 is the working timing figure of the capacitance-type sensing device 1 shown in Fig. 2.In order to each signal of clear differentiation, in Figure 12, corresponding sign is all done to each signal, the first constant DC signal provided as current source 111 adopts I1 to indicate, and the current signal that secondary signal line G22 and the 3rd signal wire G23 exports adopts I2 and I3 to carry out indicating etc. respectively.What need again to illustrate is, in other embodiments, described capacitance-type sensing device 1 is in the process of work, described ground wire 133, described earth terminal 110 can always connection device ground, so, in the present embodiment, preferably, described ground wire 133 receives modulation signal M, first reference signal R1 and the second reference signal R2 is the signal modulated through modulation signal M, thus described first reference signal R1 and described second reference signal R2 raises with the rising of described modulation signal M, reduces with the reduction of described modulation signal M.Because described modulation signal M comprises the drive singal W higher than ground signalling G; therefore; the reference signal that described sensing electrode 14 loads (namely; first reference signal R1) relatively raised when described modulation signal M is in drive singal W; thus improve driving force; and then; when described capacitive device 1 is such as fingerprint sensing device; time it is arranged on below the cover sheet (coverlens) of electronic equipment, also more easily can sense the fingerprint image of user.
So, the present invention non-limiting ground wire 133, earth terminal 110 receive modulation signal M, change ground, in other embodiments, capacitance type sensor 13 and control circuit 11 include as power end, voltage difference between described power end and described ground wire 133 (earth terminal 110) is the power supply of capacitance type sensor 13 (control circuit 11), and described power end is for receiving modulation signal M.In addition, described modulation signal M also and non-limitingly comprise ground signalling G and drive singal W, in other embodiments, described modulation signal M also can comprise the square-wave signal that negative voltage and positive voltage are formed, or the square-wave signal that ground signalling and negative voltage are formed (now, drive singal is ground voltage, lower than ground signalling), or the ladder square-wave signal of multiple voltage formation etc., preferably, when control circuit 15 adopts positive level driving sensing electrode 14 in advance, the drive singal W of preferred modulation signal M is positive level, relatively, when control circuit 15 adopts negative level driving sensing electrode 14 in advance, the drive singal W of preferred modulation signal M is negative level.In addition, modulation signal M also can adopt sinusoidal wave grade for other suitable waveform signal except adopting square-wave signal.
Due to the negligible amounts of the sensing unit 131 shown in Fig. 2, in order to embody blocked scan, see also Figure 13, the part block diagram that Figure 13 is capacitance type sensor 13 shown in Fig. 1.Multiple sensing units 131 shown in Figure 13 have been divided into 4 regions, are respectively B1, B2, B3 and B4.Described control circuit 11 scans successively to described 4 regions B1, B2, B3 and B4.So, the present invention is not limited to aforementioned scan mode, also can be other scan mode, as change each region B1, B2, B3 and B4 scanning sequency, also can be varied for the division of scanning area etc.
In addition, in principles illustrated below, be the time performing scanning for every a line sensing unit 131 of each region B1, B2, B3 and B4 be T, described time T comprises two charge period t1 and t3 and two sensing period t2 and t4 and be described.So, described capacitance-type sensing device 1 is in the process of real work, and the time T that every a line sensing unit 131 of each region B1, B2, B3 and B4 performs scanning comprised more than multiple charge period of two charge period t1 and t3 and the multiple sensing periods more than two sensing period t2 and t4.
The principle of work of described capacitance-type sensing device 1 is as follows:
In sweep time T, current source 111 is connected with the sensing unit 131 in the B1 of region by the 3rd switch element K3 with treatment circuit 113.Current source 111 provides the first constant DC signal I1, and size is I.
In sweep time T, described earth terminal 110 and ground wire 133 receive modulation signal M.Preferably, described modulation signal M comprises drive singal W at sensing period t2 and t4, is ground signalling G at charge period t1 and t3.
In sweep time T, described reference signal generation circuit 117 provides the first reference signal R1, the second reference signal R2 respectively to the reference signal line R be connected with the 9th transmission electrode S9 and the reference signal line R be connected with the 11 transmission electrode S11.Wherein, the first reference signal R1, the second reference signal R2 change with the change of modulation signal M, and modulated signals M modulates.
In sweep time T, described scan drive circuit 115 provides the first level H1 of the first sweep signal Y1 to the first sweep trace G11 be connected with the first row sensing unit 131 in the B1 of region and the second sweep trace G12.Wherein, described first sweep signal Y1 changes with the change of modulation signal M, and modulated signals M modulates.Correspondingly, the first transistor T1 and the transistor seconds T2 that are arranged in region B1 the first row sensing unit 131 are switched on, and described sensing unit 131 is activated.
At charge period t1, described scan drive circuit 115 provides the first level H1 of the second sweep signal Y2 to the three scan line G13 be connected with the first row sensing unit 131 in the B1 of region.Meanwhile, described scan drive circuit 115 provides the second electrical level H2 of the 3rd sweep signal Y3 to the 4th sweep trace G13 be connected with the first row sensing unit 131 in the B1 of region.Correspondingly, in the region B1 be connected with three scan line G13, the 5th transistor T5, the 6th transistor T6 of the first row sensing unit 131 is switched on, in the region B1 be connected with the 4th sweep trace G14, the 7th transistor T7, the 8th transistor T8 of the first row sensing unit 131 is cut off, thus, first reference signal R1 is transferred to the 3rd control electrode C3 by the 13 transmission electrode S13, the 14 transmission electrode S14 of phase short circuit in the 5th transistor T5 of conducting and the 7th transistor T7 of cut-off, charges to sensing electrode 14 and the 3rd control electrode C3; Second reference signal R2 is transferred to the 4th control electrode C4 by the 15 transmission electrode S15, the 16 transmission electrode S16 of phase short circuit in the 6th transistor T6 of conducting and the 8th transistor T8 of cut-off, charges to the 4th control electrode C4.If the signal that the 6th transmission electrode S6 exports is I2, the signal that the 8th transmission electrode S8 exports is I3, and accordingly, recharge here period t1, and described signal I2 and I3 is the second constant DC signal, and size is I/2.
At sensing period t2, described scan drive circuit 115 provides the second electrical level H2 of the second sweep signal Y2 to the three scan line G13 be connected with the first row sensing unit 131 in the B1 of region.Meanwhile, described scan drive circuit 115 provides the first level H1 of the 3rd sweep signal Y3 to the 4th sweep trace G13 be connected with the first row sensing unit 131 in the B1 of region.Correspondingly, 5th transistor T5 of the first row sensing unit 131 in the region B1 be connected with three scan line G13, 6th transistor T6 is cut off, 7th transistor T7 of the first row sensing unit 131 in the region B1 be connected with the 4th sweep trace G14, 8th transistor T8 is switched on, thus, described sensing electrode 14 may be used for performing sense operation, in addition, 7th transistor T7 of conducting compensates the voltage between the tenth transmission electrode S10 and the 3rd control electrode C3, 8th transistor T8 of conducting compensates the voltage between the 12 transmission electrode S12 and the 4th control electrode C4.
Can find out, at this sensing period t2, the drive singal W of the first sweep signal Y1, the second sweep signal Y2, the 3rd sweep signal Y3, the first reference signal R1 and the equal modulated signals M of the second reference signal R2 raises, and the first reference signal R1 relative modulation signal M does not change.Correspondingly, the signal I2 that exports of the 6th transmission electrode S6 and the signal I3 that exports of the 8th transmission electrode S8 remains unchanged.Secondary signal line G22 transmit second constant DC signal I2 and I3 corresponding to the 3rd signal wire G23 is to treatment circuit 113.Described treatment circuit 113 according to described second constant DC signal I2 know do not have target object close to or touch this sensing electrode 14.
It should be noted that, if do not arrange the 7th transistor T7, when the 5th transistor T5 ends, charge carrier (electronics or the hole at the tenth transmission electrode S10 place, determine according to the type of the 5th transistor T5) impact can be had on the voltage of the 3rd control electrode C3, relatively, when arranging the 7th transistor T7, 7th transistor T7 of conducting can absorb described charge carrier or discharge the charge carrier (specifically according to the type selecting of five transistor T5) electrically contrary with described charge carrier when the 5th transistor T5 ends, thus keep the voltage relative modulation signal M at the 3rd control electrode C3 place to remain unchanged.Similarly, the 8th transistor T8 is set, remains unchanged to keep the voltage relative modulation signal M at the 4th control electrode C4 place.
At charge period t3, similar or identical with the charging principle of charge period t1, the first reference signal R1 is supplied to the 3rd control electrode C3 again, charges to the 3rd control electrode C3; Second reference signal R2 is supplied to the 4th control electrode C4 again, charges to the 4th control electrode C4.Recharge here period t3, and described signal I2 and I3 is the second constant DC signal, and size is I/2.
At sensing period t4, similar or identical with the principle of work of sensing period t2, only, first reference signal R1 relative modulation signal M changes, correspondingly, described differential pair tube D corresponds to the 6th transmission electrode S6 and the 8th transmission electrode S8 and forms two different the second AC signal (I/2)+i, (I/2)-i, and respectively by secondary signal line G22 and the 3rd signal wire G23 parallel transmission to treatment circuit 113.Described treatment circuit 113 according to described second AC signal (I/2)+i, (I/2)-i know have target object close to or touch this sensing electrode 14.
As mentioned above, the first row sensing unit 131 in the B1 of region is completed by scanning.Next, can adopt and to line by line scan or the sensing unit 131 of interleaved mode to other row in the B1 of region carries out as above similar scanning, thus complete the scanning to whole region B1.Similarly, complete the scanning to other region B2, B3 and B4 successively, and then complete the scanning to whole capacitance type sensor 13.About the concrete scanning process of the sensing unit 131 for other row sensing unit 131 in the B1 of region and other region B2, B3 and B4, repeat no more herein.
What the control circuit 11 due to capacitance-type sensing device 1 of the present invention received is from the sensing signal of capacitance type sensor 13 is differential current signal, and therefore, the sensing precision of described capacitance-type sensing device 1 can be improved, thus is conducive to promoting Consumer's Experience.
In the principle of work of embodiment above, two charge period t1 and t3 are comprised with described time T, and two sensing period t2 and t4 be that example is described, so, change ground, in other embodiments, described time T comprises two electric discharge period t1 and t3, and two sense period t2 and t4, correspondingly, the drive singal of described modulation signal M is negative level, described reference signal generation circuit 117 is supplied to the first reference signal R1 of differential pair tube D and the second reference signal R2 and corresponds to negative level, namely, to sensing electrode 14, 3rd control electrode C3, and the 4th control electrode C4 discharge, this, namely section was defined as the period of discharging discharge time.
Refer to Figure 14, Figure 14 is the electrical block diagram of the second embodiment of capacitance-type sensing device of the present invention.Capacitance-type sensing device 2 is with the difference of capacitance-type sensing device 1: the first, and the structure of the sensing unit 231 of the capacitance type sensor 23 of capacitance-type sensing device 2 is slightly different from the structure of the sensing unit 131 of the capacitance type sensor 13 of capacitance-type sensing device 1; The second, the control circuit 21 control capacitance formula sensor 23 of capacitance-type sensing device 2 performs the principle of work that the principle of work sensed slightly is different from the control circuit 11 control capacitance formula sensor 13 execution sensing of capacitance-type sensing device 1.The structure distinguished capacitance-type sensing device 2 and capacitance-type sensing device 1 below and principle of work carry out related description, so, the more similar or identical part of capacitance-type sensing device 2 and capacitance-type sensing device 1, repeat no more herein, for those skilled in the art, its basis, can without the need to creative work natural expansion on described capacitance-type sensing device 2 above to the description of the structure & working mechanism of capacitance-type sensing device 1.
See also Figure 15 and Figure 16, Figure 15 is the electrical block diagram of two sensing units 231 adjacent on a column direction shown in Figure 14.Figure 16 is the part circuit structure schematic diagram of the capacitance-type sensing device 2 of Figure 14.Below describe for two adjacent sensing units 231 and target object is described for finger F, the structure & working mechanism of other sensing unit 231 is similar, repeats no more.Described sensing circuit 25 comprises change-over circuit 251.Described change-over circuit 251 is for responding sensing electrode 24 because of the close of finger F or the change touching caused reference signal, and corresponding generation the second AC signal.Preferably, described change-over circuit 251 change sensing electrode 24 because of finger F close to or the variable quantity that touches caused reference signal be the first AC signal, and superpose on described first AC signal to one second constant DC signal, described second AC signal of corresponding generation.Preferably, described first AC signal and the second AC signal are current signal.So, in other embodiments, described second AC signal also can be voltage signal.
In the present embodiment, described change-over circuit 251 comprises third transistor N3.Described third transistor N3 responds sensing electrode 24 because of the close of finger F or the change touching caused reference signal, and correspondence produces the second AC signal.Preferably, described third transistor N3 changes and amplifies the variable quantity of sensing electrode 24 because of the reference signal caused by the close of target object or touch, described second AC signal of corresponding generation.
Described third transistor N3 is used for forming differential pair tube (sign) with the third transistor N3 of neighboring sensor unit 231.Such as, for the third transistor N3 of a sensing unit 231: for forming differential pair tube with the third transistor N3 of adjacent sensing unit 231 on line direction; Or/and, for forming differential pair tube with the third transistor N3 of adjacent sensing unit 231 on column direction.
Preferably, the third transistor N3 of the third transistor N3 of described each sensing unit 231 neighboring sensor unit 231 of diverse location in timesharing and line direction and column direction forms differential pair tube respectively.That is, two sensing units 231 of arbitrary neighborhood are for forming a sensing unit group 233 (see Figure 15).In the present embodiment, the sensing unit of same row 231 shares a current source 211, with the third transistor N3 of sensing unit 231 adjacent in a line when needs composition differential pair tube, shares a current source 211 (see Figure 14).
When capacitance type sensor 23 performs sensing, be electrically connected with same current source 211 two is adjacent and third transistor N3 in the sensing unit 231 be activated forms differential pair tube, described two adjacent and the 5th transmission electrode P5 of third transistor N3 in the sensing unit 231 be activated is electrically connected same current source 211.By the component properties of differential pair tube, for described two adjacent and sensing units 231 be activated: be no matter sensing electrode 24 in one of them sensing unit 231 or two sensing units 231 by target object close to or when touching the change of caused reference signal, third transistor N3 in described two sensing units 231 forms the second AC signal respectively on the 6th transmission electrode P6, and the second AC signal that two third transistor N3 are formed respectively is with width with same frequency and reversed-phase, for differential signal, sum of the two is equal with the first constant DC signal that described current source 211 provides.
Preferably, the sensing circuit 25 of described each sensing unit 231 comprises the first switch element Q1 further.Described first switch element Q1 is connected between the 5th transmission electrode P5 and described current source 211, for controlling whether carry out current delivery between described 5th transmission electrode P5 and described current source 211.
Described first switch element Q1 comprises the first transistor N1.Described the first transistor N1 comprises the first control electrode V1, the first transmission electrode P1 and the second transmission electrode P2.Described first control electrode V1 to control between the first transmission electrode P1 and the second transmission electrode P2 whether conducting for responding one scan signal correspondence.First transmission electrode P1 is for connecting described current source 211.Second transmission electrode P2 is for connecting described 5th transmission electrode P5.
Preferably, described first switch element Q1 comprises transistor seconds N2 further.Described transistor seconds N2 comprises the second control electrode V2, the 3rd transmission electrode P3 and the 4th transmission electrode P4.Described second control electrode V2 to control between the 3rd transmission electrode P3 and the 4th transmission electrode P4 whether conducting for responding one scan signal correspondence.3rd transmission electrode P3 is for connecting the second transmission electrode P2.
More preferably, described sensing circuit 25 comprises second switch unit Q2 further.Described second switch unit Q2 is used for controlling whether to transmit the first reference signal to the 3rd control electrode V3.Third transistor N3 is associated with sensing electrode 24, and therefore, second switch unit Q2 correspondence controls whether transmission of reference signals is to described sensing electrode 24.
In the present embodiment, described 3rd control electrode V3 and described sensing electrode 24 are two electrodes, and described 3rd control electrode V3 directly connects described sensing electrode 24.In other embodiments, described 3rd control electrode V3 also connects described sensing electrode 24 by current limiting element, and described current limiting element comprises resistance, plays the effect of anti-ESD.In addition, described 3rd control electrode V3 and described sensing electrode 24 also can be same electrode.
Preferably, described second switch unit Q2 comprises the 5th transistor N5.Described 5th transistor N5 comprises the 5th control electrode V5, the 9th transmission electrode P9 and the tenth transmission electrode P10.Wherein, the 5th control electrode V5 corresponding controls the 9th transmission electrode P9 and the tenth transmission electrode P10 whether conducting for responding one scan signal.9th transmission electrode P9 is for receiving the first reference signal.Tenth transmission electrode P10 connects the 3rd control electrode V3.
More preferably, described sensing circuit 25 comprises the first compensating unit U1 further.Described first compensating unit U1 is arranged between the tenth transmission electrode P10 and the 3rd control electrode V3, for compensating voltage when the 5th transistor N5 closes between the tenth transmission electrode P10 and the 3rd control electrode V3.
Preferably, described first compensating unit U1 comprises the 7th transistor N7.Described 7th transistor N7 comprises the 7th control electrode V7, the 13 transmission electrode P13 and the 14 transmission electrode P14.Wherein, the 7th control electrode V7 controls the 13 transmission electrode P13 and the 14 transmission electrode P14 whether conducting for responding one scan signal.13 transmission electrode P13 connects the tenth transmission electrode P10.14 transmission electrode P14 connects the 3rd control electrode V3.13 transmission electrode P13 and the 14 transmission electrode P14 short circuit.
7th transistor N7 is used for and the 5th transistor N5 alternate conduction, and the 7th transistor N7 of conducting compensates the voltage between the 3rd control electrode V3 and the tenth transmission electrode P10 when the 5th transistor N5 ends.
Referring again to Figure 15 and Figure 16, described capacitance type sensor 23 comprises multiple sweep trace group G3, multiple signal wire group G4 and many reference signal line X further.Wherein, described sweep trace group G3 is for transmitting scanning-line signal to described multiple sensing unit 231.Described signal wire group G4 is used for transmission current signal between described multiple sensing unit 231 and described control circuit 21.Described many reference signal line X are for transmitting the first reference signal to described multiple sensing unit 231.
Described sweep trace group G3 comprises the first sweep trace G31, the second sweep trace G32, three scan line G33 and the 4th sweep trace G34.Described signal wire group G4 comprises the first signal wire G41, secondary signal line G42 and the 3rd signal wire G43.
The 6th transmission electrode P6 for the third transistor N3 of be arranged in same row two adjacent sensing unit 231: sensing units 231 is used for being connected with secondary signal line G42, and the 6th transmission electrode P6 of the third transistor N3 in another sensing unit 231 is used for being connected with the 3rd signal wire G43; The 5th transmission electrode P5 of the third transistor N3 of described two adjacent sensing units 231 is connected by same first signal wire G41.
For each signal wire group G4: described first signal wire G41, secondary signal line G42 and the 3rd signal wire G43 extend along column direction, and described first signal wire G41, secondary signal line G42 and the 3rd signal wire G43 arrange in the row direction successively.
In the present embodiment, the sensing unit 231 of odd-numbered line all connects secondary signal line G42, and the sensing unit 231 of even number line all connects the 3rd signal wire G43.Change ground, in other embodiments, the sensing unit 231 of odd-numbered line all connects the 3rd signal wire G43, and the sensing unit 231 of even number line all connects secondary signal line G42.
First sweep trace G31 and the second sweep trace G32 insulate cross arrangement.
Preferably, the control electrode V3 of the first transistor N3 of same row is connected to same first sweep trace G31.The second control electrode V2 with the transistor seconds N2 of a line is connected to same second sweep trace G32.The 5th control electrode V5 with the 5th transistor N5 of a line is connected to same three scan line G33.The 7th control electrode V7 with the 7th transistor N7 of a line is connected to same 4th sweep trace G34.The 9th transmission electrode P9 with the 5th transistor N5 of a line is connected to same reference signal line X.
Multiple sensing units 231 due to capacitance type sensor 23 respond sensing electrode 24 because of the close of target object or the change touching caused reference signal, and corresponding second AC signal that produces is to control circuit 21, therefore, the sensing signal that exports of capacitance type sensor 23 is comparatively strong and stability is higher.
The principle of work of described capacitance-type sensing device 2 is as follows.
In the present embodiment, preferably, described capacitance-type sensing device 2 adopts the mode of blocked scan to work.So, in other embodiments, also can without the need to blocked scan, but complete scan a line each time, by Multiple-Scan, complete the scanning of all sensing units 231 to whole capacitance type sensor 23.
See also Figure 17, Figure 17 is the frame structure schematic diagram of capacitance type sensor 23.Similar with Figure 13, the multiple sensing units 231 shown in Figure 14 have been divided into 4 regions, are respectively J1, J2, J3 and J4.Multiple sensing units 231 in described scanning block J1 are labeled as a11 ~ a55 by the mode of row-column arrangement, in scanning block J2, the sensing unit adjacent with sensing unit a55 is denoted as a56, and in scanning block J3, the sensing unit adjacent with sensing unit a55 is denoted as a65.Herein, mainly to be described the scan mode of the sensing unit 231 in scanning block J1, the scan mode of the sensing unit 231 in other scanning block J2, J3 and J4 is similar, repeats no more herein.In addition, scan drive circuit 215 drives the principle of work of the first switch element Q1 and second switch unit Q2 alternate conduction, sensing circuit 25 provides the first reference signal to charge to the 3rd control electrode V3 at charge period, stop providing the first reference signal to the 3rd control electrode V3 in the sensing period, the principle of work that sensing electrode 24 correspondence performs sensing in the sensing period is all similar with the principle of work of capacitance-type sensing device 1, also repeats no more herein.The main principle of work difference to capacitance-type sensing device 2 and capacitance-type sensing device 1 is described below.
First, it should be noted that, such as, for capacitance-type sensing device 2 for for fingerprint sensing device, usually, multiple sensing unit 231 is set between adjacent fingerprint ridge and fingerprint paddy usually.
Secondly, sensing unit 131 due to capacitance-type sensing device 1 comprises a differential pair tube D all separately, therefore, it is absolute value that described sensing unit 131 senses the second AC signal obtained, control circuit 11 is compared by the sensing signal exported each sensing unit 131, then may correspond to acquisition information in fingerprint.Relatively, because the third transistor N3 of the neighboring sensor unit 231 of capacitance-type sensing device 2 is for forming a differential pair tube, therefore, each sensing unit 231 senses the second AC signal obtained is not absolute value as described above.
In order to obtain information in fingerprint, preferably, the third transistor N3 of all adjacent sensing unit 231 of the third transistor N3 of each sensing unit 231 and its line direction and column direction is needed to form differential pair tube respectively, thus, obtain many group sensing numerical value, do subtraction to the adjacent sensing numerical value obtained again and obtain many group sensing differences, described control circuit 21 by comparing described many group sensing differences, then may correspond to acquisition information in fingerprint.
The scanning process of described control circuit 21 to the multiple sensing units 231 in described scanning block J1 is as follows:
First, the described control circuit 21 first independent sensing unit 231 to the first row carries out first time scanning, now, third transistor N3 in third transistor N3 in sensing unit a11 and sensing unit a12 forms differential pair tube, third transistor N3 in third transistor N3 in sensing unit a13 and sensing unit a14 forms differential pair tube, and described control circuit 21 obtains sensing signal Y1, Y2 respectively.
The described control circuit 21 more independent sensing unit 231 to the first row carries out second time scanning, now, third transistor N3 in third transistor N3 in sensing unit a12 and sensing unit a13 forms differential pair tube, third transistor N3 in third transistor N3 in sensing unit a14 and sensing unit a15 forms differential pair tube, and described control circuit 21 obtains sensing signal Y3, Y4 respectively.
Control circuit 21 takes turns doing subtraction to sensing signal Y1, Y3, Y2, Y4 of obtaining, obtains sensing difference △ Y1, △ Y2, △ Y3 respectively.
Next, control circuit 21 scans the sensing unit 231 of the first row and the second row simultaneously, two sensing units 231 that same row are adjacent, as a11 and a21, third transistor N3 form differential pair tube, described control circuit 21 obtains sensing signal Y5, Y6, Y7, Y8, Y9 (sign) respectively.
Control circuit 21 takes turns doing subtraction to sensing signal Y5, Y6, Y7, Y8, Y9 of obtaining, obtains sensing difference △ Y4, △ Y5, △ Y6, △ Y7 (sign) respectively.
Following again, control circuit 21 carries out first time scanning to the sensing unit 231 of the second row separately, wherein, third transistor N3 in third transistor N3 in sensing unit a21 and sensing unit a22 forms differential pair tube, third transistor N3 in third transistor N3 in sensing unit a23 and sensing unit a24 forms differential pair tube, and described control circuit 21 obtains sensing signal Y10, Y11 (sign) respectively.
The described control circuit 21 more independent sensing unit 231 to the second row carries out second time scanning, wherein, third transistor N3 in third transistor N3 in sensing unit a22 and sensing unit a23 forms differential pair tube, third transistor N3 in third transistor N3 in sensing unit a24 and sensing unit a25 forms differential pair tube, and described control circuit 21 obtains sensing signal Y12, Y13 (sign) respectively.
Control circuit 21 takes turns doing subtraction to sensing signal Y10, Y12, Y11, Y13 of obtaining, obtains sensing difference △ Y8, △ Y9, △ Y10 (sign) respectively.
Next, control circuit 21 scans the sensing unit 231 of the second row and the third line simultaneously.
According to as above scan mode, the sensing unit 231 of other row of J1 in scanning block is scanned, similarly, the sensing unit 231 of other scanning block J2, J3, J4 is scanned, thus the scanning completed all sensing units 231, obtain many group sensing difference △ Y1, △ Y2 ..., described control circuit 21 compares many groups of sensing differences of acquisition to know information in fingerprint.
It should be noted that, more accurate in order to sense, the sensing unit 231 for scanning block J1 edge: also need form differential pair tube with the third transistor N3 of the sensing unit 231 of other adjacent scan areas J2, J3, acquisition sensing signal.Such as, for sensing unit a55: the sensing unit a55 in the third transistor N3 in sensing unit a55 and sensing unit a56 and a65 forms differential pair tube more respectively.
Control sensing unit 231 to control circuit 21 above to perform scan operation and done general explanation; so; the scan mode of capacitance-type sensing device 2 of the present invention is not limited to the above; for a person skilled in the art; it is not paying on the basis of creative work, all should fall into protection scope of the present invention according to other change embodiment that the above-mentioned description of the present invention is made.
The sensing signal that control circuit 21 due to capacitance-type sensing device 2 receives from capacitance type sensor 23 is current signal, and is differential signal, and therefore, the sensing precision of described capacitance-type sensing device 2 can be improved, thus is conducive to promoting Consumer's Experience.
Although be open to describe the present invention with reference to each embodiment, be appreciated that these embodiments are illustrative, and scope of the present invention is not limited only to them.Many changes, amendment, interpolation and improvement are all possible.More generally, describe in the context of specific embodiments according to each embodiment disclosed by the invention.Function can be separated in a different manner during the course or combination in each embodiment disclosed by the invention, or utilizes different terms to describe.These and other change, amendment, adding and improve can in such as scope as defined in the claims disclosed by the invention subsequently.
Claims (13)
1. a sensing unit for capacitance type sensor, comprising:
Sensing electrode, can be coupled to target object in a capacitive manner, for loading reference signal; With
Sensing circuit, comprises differential pair tube, is associated with described sensing electrode, for responding because of the close of target object or the change touching caused reference signal on sensing electrode, and the second AC signal that corresponding generation two is different.
2. sensing unit as claimed in claim 1, is characterized in that: described two different the second AC signal are differential current signal.
3. sensing unit as claimed in claim 1, is characterized in that: described differential pair tube comprises:
Third transistor, comprises the 3rd control electrode, the 5th transmission electrode and the 6th transmission electrode, and wherein, the 6th transmission electrode is for transmitting the second AC signal; 3rd control electrode and sensing electrode are two electrodes, and the 3rd control electrode connects sensing electrode, or the 3rd control electrode and sensing electrode are same electrode; 3rd control electrode is for loading the first reference signal; With
4th transistor, comprises the 4th control electrode, the 7th transmission electrode and the 8th transmission electrode, and wherein, the 4th control electrode is for loading the second reference signal; 7th transmission electrode and the 5th transmission electrode are used for being connected with a current source; 8th transmission electrode is for transmitting the second AC signal.
4. sensing unit as claimed in claim 3, it is characterized in that: described sensing circuit comprises the first switch element further, first switch element is connected between described differential pair tube and described current source, for controlling whether carry out current delivery between described differential pair tube and described current source.
5. sensing unit as claimed in claim 4, it is characterized in that: described sensing circuit comprises second switch unit further, whether transmit the first reference signal and the second reference signal to described differential pair tube for controlling, wherein, the first reference signal is identical with the second reference signal.
6. sensing unit as claimed in claim 5, it is characterized in that: described capacitance type sensor comprises the first signal wire, secondary signal line, the 3rd signal wire, the first sweep trace and the second sweep trace, described 7th transmission electrode is connected the first signal wire with the 5th transmission electrode by the first switch element; 6th transmission electrode is used for being connected with secondary signal line; 8th transmission electrode is used for being connected with the 3rd signal wire; Described first switch element comprises:
The first transistor, comprise the first control electrode, the first transmission electrode and the second transmission electrode, wherein, described first control electrode is connected with the first sweep trace, described first transmission electrode is used for being connected with the first signal wire, and described second transmission electrode is used for being connected with the 5th transmission electrode; With
Transistor seconds, described transistor seconds comprises the second control electrode, the 3rd transmission electrode and the 4th transmission electrode, and wherein, the second control electrode is used for being connected with the second sweep trace; 3rd transmission electrode is connected with the second transmission electrode; 4th transmission electrode is connected with the 5th transmission electrode.
7. sensing unit as claimed in claim 6, it is characterized in that: described capacitance type sensor comprises three scan line and reference signal line further, described second switch unit comprises:
5th transistor, comprises the 5th control electrode, the 9th transmission electrode and the tenth transmission electrode, and wherein, the 5th control electrode is used for being connected with a three scan line; 9th transmission electrode is for connecting a reference signal line; Tenth transmission electrode connects the 3rd control electrode; Wherein, the 3rd control electrode is for receiving from the first reference signal on reference signal line by the 5th transistor; With
6th transistor, comprises the 6th control electrode, the 11 transmission electrode and the 12 transmission electrode, and wherein, the 6th control electrode is used for being connected with a three scan line; 11 transmission electrode is for connecting a reference signal line; 12 transmission electrode connects the 4th control electrode; Wherein, the 4th control electrode is for receiving from the second reference signal on reference signal line by the 6th transistor.
8. sensing unit as claimed in claim 7, is characterized in that: described capacitance type sensor comprises the 4th sweep trace further, and described sensing unit comprises further:
7th transistor, comprises the 7th control electrode, the 13 transmission electrode and the 14 transmission electrode, and wherein, the 7th control electrode is for connecting one the 4th sweep trace; 13 transmission electrode connects the tenth transmission electrode; 14 transmission electrode connects the 3rd control electrode; 13 transmission electrode and the 14 transmission electrode short circuit; With
8th transistor, comprises the 8th control electrode, the 15 transmission electrode and the 16 transmission electrode, and wherein, the 8th control electrode is for connecting one the 4th sweep trace; 15 transmission electrode connects the 12 transmission electrode; 16 transmission electrode connects the 4th control electrode; 15 transmission electrode and the 16 transmission electrode short circuit.
9. sensing unit as claimed in claim 8, is characterized in that: the 5th control electrode and the 6th control electrode short circuit are also connected to same three scan line; 9th transmission electrode and the 11 transmission electrode short circuit are also connected to same reference signal line; 7th control electrode and the 8th control electrode short circuit and be connected to same 4th sweep trace.
10. sensing unit as claimed in claim 8, is characterized in that: the 7th transistor is used for and the 5th transistor alternate conduction, and the 7th transistor of conducting compensates the voltage between the 3rd control electrode and the tenth transmission electrode when the 5th transistor cutoff; 8th transistor is used for and the 6th transistor alternate conduction, and the 8th transistor of conducting compensates the voltage between the 4th control electrode and the 12 transmission electrode when the 6th transistor cutoff.
11. sensing units as claimed in claim 3, it is characterized in that: described capacitance type sensor comprises the substrate for carrying sensing unit further, when described sensing electrode and described 3rd control electrode are two electrodes, described sensing circuit is arranged between described sensing electrode and described substrate, and in the structure of described sensing circuit, contact hole is set, described sensing electrode is connected with described 3rd control electrode by described contact hole; When described sensing electrode and described 3rd control electrode are same electrode, described 3rd control electrode is arranged compared to the 5th transmission electrode and the contiguous described substrate of the 6th transmission electrode.
12. sensing units as claimed in claim 3, it is characterized in that: described differential pair tube on sensing electrode because of target object close to or the variable quantity of reference signal caused by touching change and amplify, produce two the first different AC signal, and two different the first AC signal are superimposed on the second identical constant DC signal respectively, corresponding produce described two different the second AC signal, wherein, the half of the first constant DC signal that provides for described current source of the second constant DC signal.
13. sensing units as claimed in claim 1, is characterized in that: the sensing unit of described capacitance type sensor is the sensing unit of fingerprint sensor.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510612657.8A CN105138207A (en) | 2015-09-23 | 2015-09-23 | Sensing unit of capacitive sensor |
| PCT/CN2016/094470 WO2017050043A1 (en) | 2015-09-23 | 2016-08-10 | Sensor unit of capacitive sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510612657.8A CN105138207A (en) | 2015-09-23 | 2015-09-23 | Sensing unit of capacitive sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN105138207A true CN105138207A (en) | 2015-12-09 |
Family
ID=54723573
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201510612657.8A Pending CN105138207A (en) | 2015-09-23 | 2015-09-23 | Sensing unit of capacitive sensor |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN105138207A (en) |
| WO (1) | WO2017050043A1 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2017050043A1 (en) * | 2015-09-23 | 2017-03-30 | 深圳信炜科技有限公司 | Sensor unit of capacitive sensor |
| WO2017050046A1 (en) * | 2015-09-23 | 2017-03-30 | 深圳信炜科技有限公司 | Sensor unit of capacitive sensor and sensor unit set |
| CN106971138A (en) * | 2016-08-09 | 2017-07-21 | 深圳信炜科技有限公司 | The sensing unit of capacitance type sensor |
| CN111144346A (en) * | 2019-12-30 | 2020-05-12 | 厦门天马微电子有限公司 | Fingerprint identification detection circuit, fingerprint scanning circuit and display device |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6191989B1 (en) * | 2000-03-07 | 2001-02-20 | International Business Machines Corporation | Current sensing amplifier |
| GB2405701A (en) * | 2003-09-03 | 2005-03-09 | Seiko Epson Corp | Differential current sensing circuit |
| CN104809448B (en) * | 2015-05-08 | 2017-03-15 | 京东方科技集团股份有限公司 | Fingerprint sensor and display device |
| CN105138207A (en) * | 2015-09-23 | 2015-12-09 | 深圳信炜科技有限公司 | Sensing unit of capacitive sensor |
-
2015
- 2015-09-23 CN CN201510612657.8A patent/CN105138207A/en active Pending
-
2016
- 2016-08-10 WO PCT/CN2016/094470 patent/WO2017050043A1/en active Application Filing
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2017050043A1 (en) * | 2015-09-23 | 2017-03-30 | 深圳信炜科技有限公司 | Sensor unit of capacitive sensor |
| WO2017050046A1 (en) * | 2015-09-23 | 2017-03-30 | 深圳信炜科技有限公司 | Sensor unit of capacitive sensor and sensor unit set |
| CN106971138A (en) * | 2016-08-09 | 2017-07-21 | 深圳信炜科技有限公司 | The sensing unit of capacitance type sensor |
| CN111144346A (en) * | 2019-12-30 | 2020-05-12 | 厦门天马微电子有限公司 | Fingerprint identification detection circuit, fingerprint scanning circuit and display device |
| CN111144346B (en) * | 2019-12-30 | 2022-08-16 | 厦门天马微电子有限公司 | Fingerprint identification detection circuit, fingerprint scanning circuit and display device |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2017050043A1 (en) | 2017-03-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105138206A (en) | Capacitive sensing device and electronic equipment | |
| CN105138181A (en) | Capacitive sensor, capacitive sensing device and electronic device | |
| CN105159517A (en) | Capacitive sensing device and capacitive sensing system | |
| CN105138203A (en) | Capacitive sensing system and electronic equipment | |
| CN105159518A (en) | Capacitive sensing device, package structure, sensing module and electronic equipment | |
| CN105224155A (en) | Capacitance type sensor, sensing device, sensing system and electronic equipment | |
| CN105988649B (en) | Touch control display apparatus and its driving method | |
| CN105138207A (en) | Sensing unit of capacitive sensor | |
| CN104461201A (en) | Touch display device and drive method thereof | |
| CN205028275U (en) | Chipset and electronic equipment | |
| CN105138205A (en) | Capacitive sensor, sensing device, sensing system and electronic device | |
| CN205028269U (en) | Capacitive sensor's sensing unit and sensing unit group | |
| CN105739768A (en) | Touch display panel and touch display equipment | |
| CN205080536U (en) | Capacitive sensor , sensing device , sensing system and electronic equipment | |
| CN107704145B (en) | Display panel, control method thereof and display device | |
| CN205080535U (en) | Capacitive sensor and electronic equipment | |
| CN101140366A (en) | Sensing-objects touching pixel unit, method and display apparatus thereof | |
| CN205158325U (en) | Capacitive sensor , packaging structure , sensing module and electronic equipment | |
| CN205334405U (en) | Touching device , touch display apparatus and electronic equipment | |
| CN105183258A (en) | Sensing unit of capacitive sensor and sensing unit group | |
| CN205028267U (en) | Capacitive sensor's sensing unit | |
| CN205028266U (en) | Capacitive sensor , sensing device , sensing system and electronic equipment | |
| CN205028270U (en) | Capacitive sensor , sensing device , sensing system and electronic equipment | |
| CN205068351U (en) | Capacitanc sensing system and electronic equipment | |
| CN205080387U (en) | Electronic equipment |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| CB02 | Change of applicant information |
Address after: Guangdong province Shenzhen city Nanshan District District 518055 Xili street honghualing Industrial District 2 District 1 Building 5 floor (Xi Bian) Applicant after: SHENZHEN SUNWAVE TECHNOLOGY CO., LTD. Address before: 518052 Guangdong city of Shenzhen province Qianhai Shenzhen Hong Kong cooperation zone before Bay Road No. 1 building 201 room A Applicant before: SHENZHEN SUNWAVE TECHNOLOGY CO., LTD. |
|
| COR | Change of bibliographic data | ||
| TA01 | Transfer of patent application right |
Effective date of registration: 20211013 Address after: No. 2208, block B, building 9, zone 2, shenzhenwan science and technology ecological park, Yuehai street, Nanshan District, Shenzhen City, Guangdong Province, 518000 Applicant after: Duntai Technology (Shenzhen) Co.,Ltd. Address before: 518055 Shenzhen, Nanshan District, Guangdong Xili Street Honghua Ling Industrial Zone 2 District 1 District 5 Building (Xi Bian) Applicant before: SHENZHEN XINWEI TECHNOLOGY Co.,Ltd. |
|
| TA01 | Transfer of patent application right |