CN101788858A - Contact detection method of capacitive touchpad and stylus thereof - Google Patents
Contact detection method of capacitive touchpad and stylus thereof Download PDFInfo
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- CN101788858A CN101788858A CN200910005982A CN200910005982A CN101788858A CN 101788858 A CN101788858 A CN 101788858A CN 200910005982 A CN200910005982 A CN 200910005982A CN 200910005982 A CN200910005982 A CN 200910005982A CN 101788858 A CN101788858 A CN 101788858A
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- pointer
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- voltage
- touch control
- control plate
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Abstract
The invention provides a contact detection method of a capacitive touchpad and a stylus thereof. The stylus comprises a pressure conducting layer, a piezoelectric element in contact with the pressure conducting layer and a support part for supporting the piezoelectric element. When the stylus is pressed on the capacitive touchpad, the pressure conducting layer transfers the pressure of the contact point, the piezoelectric element receives the pressure to generate the voltage to change the earthing potential of the contact point, and increases the voltage change value seen at the detector end, thereby improving the sensitivity of the capacitive touchpad.
Description
Technical field
The present invention is relevant a kind of capacitive touch control plate, particularly about a kind of pointer of capacitive touch control plate and contact detecting method of capacitive touch control plate of being used for.
Background technology
Trackpad has three kinds of resistance-type, electromagnetic type and condenser types.Resistor type touch control plate need utilize nib application of force on minimum area when operation, the electromagnetic touch-control plate need cooperate the special pen with battery to import.The principle of work of capacitive touch control plate is the moment of utilizing object to touch Trackpad to produce capacitance coupling effect, thereby can be by the change-detection object position contacting of capacitance, therefore capacitive touch control plate needn't be with the input pen of electric consumption, the use of capacitive touch control plate does not need compression point to concentrate yet, so serviceable life is longer.Moreover the composition of capacitive touch control plate is simple, element is few, product yields height, makes that capacitive touch control plate cost when a large amount of production is lower.
The mode of operating capacitance touch plate has many, and modal is to touch on its surface or slide with finger or pen, so that the inductor in the Trackpad produces corresponding signal.Inductor is a device that includes one dimension or two-dimentional sensor conductor, and normally etching trace (trace) forms on printed circuit board (PCB), and its structure has four layers, bilayer and individual layer, and the principle of sensing article is identical haply.In order to protect inductor and effect attractive in appearance; be coated with the level and smooth insulant of one deck on the inductor; its material is generally based on insulating gel and plastic cement shell; the effect of insulation is provided and allows user's finger touch thereon and slide, its structure reference example is as awarding to Miller people's such as (Miller) U.S. Patent number 5374787.
Though capacitive touch control plate all is being better than resistance-type and electromagnetic touch-control plate aspect performance and the cost two, the lower shortcoming of the precision of detection is arranged but.The application of capacitive touch control plate is more and more, and some application may need to detect more accurately usefulness.When the spatial resolution increase of capacitive touch control plate, the equivalent capacity of its trace reduces, and therefore needs detectability more accurately.The supply voltage that reduces capacitive touch control plate also may cause it to detect the precision reduction.This all factor causes capacitive touch control plate and improves the demand that detects precision.
Summary of the invention
One of purpose of the present invention is to propose a kind of pointer that is used for capacitive touch control plate.
One of purpose of the present invention is to propose a kind of contact detecting method of capacitive touch control plate.
According to the present invention, the support member that a kind of pointer that is used for capacitive touch control plate comprises the pressure conducting stratum, contacts the piezoelectric element of this pressure conducting stratum and support this piezoelectric element.When being pressed on this capacitive touch control plate under this pointer, this pressure conducting stratum transmits the pressure of this contact point, and this piezoelectric element receives this pressure and produces voltage.
According to the present invention, a kind of contact detecting method of capacitive touch control plate comprises exerts pressure to the contact point on this capacitive touch control plate, converts this pressure to voltage changing the earthing potential of this contact point, and detects the change in voltage on this capacitive touch control plate.
The voltage that this piezoelectric element produces changes the earthing potential of this contact point, the voltage change of this contact point is increased, thereby promote the sensitivity of this capacitive touch control plate.
Description of drawings
Fig. 1 is the equivalent circuit diagram of piezoelectric element; And
Fig. 2 is the synoptic diagram according to pointer embodiment of the present invention.
Drawing reference numeral:
10 pointer
100 nibs
102 piezoelectric elements
104 support members
105 insulation walls
106 leads
108 ground planes
20 capacitive touch control plates
22 traces
24 detecting devices
Embodiment
Piezoelectric effect (piezoelectric) is the phenomenon that a kind of mechanical energy and electric energy exchange in the material, be the earliest 1880 by Pi Aier Curie (Pierre Curie) and the fraternal discovery of refined gram Curie (Jacques Curie).It is because of special arrangement mode between atom in the lattice that piezoelectric has piezoelectric effect, makes material have the effect of stress field and field coupled.
Piezoelectric effect has two kinds: direct piezo electric effect (direct piezoelectric effect) and inverse piezoelectric effect (converse piezoelectric effect).Direct piezo electric effect is to transfer mechanical energy to electric energy, and when imposing physical pressure facing to piezoelectric, the electric coupling polar moment in the material bodies can shorten because of compression, and this moment, piezoelectric produced positive and negative charge to maintain the original state for the opposing STRESS VARIATION at material surface.Inverse piezoelectric effect is to transfer electric energy to mechanical energy, and when applying electric field (voltage) in piezoelectric material surface, electric field action makes electric dipole moment be elongated, and piezoelectric changes for opposing, can extend along direction of an electric field.
Common piezoelectric comprises barium titanate, the lead zirconate titanate (PZT) of ceramic-like, the quartz of monocrystalline class (crystal), tourmaline, Luo De salt, tantalates, niobate etc., and the zinc paste of film class (ZnO).The characteristic of piezoelectric is represented with g, g=fields/stress=(volts/meter)/(newton/meter
2), be used for representing that this piezoelectric is stressed and produce relation between electric field.Common piezoelectric, for example g of PZT
33Be 25.5 * 10
-3Vm/N, g
31Be-10.1 * 10
-3Vm/N, the g of another kind of diaphragm type piezoelectric PVDF
33Be 216 * 10
-3Vm/N, g
31Be-330 * 10
-3Vm/N.The pressure that the people refers to provide when normal running is generally between 3～5 newton.The finger area of supposing the user is 100mm
2, when the user is 200 μ m to thickness, g is 25 * 10
-3When the piezoelectric of Vm/N applies 5 newton's power, can produce 0.25 volt voltage.
Fig. 1 is the equivalent circuit diagram of piezoelectric, R
eRepresent its resistance value, C
eRepresent its capacitance, L
mExpression quality (Kg), C
mTable machinery is subdued power (mechanical compliance), and N represents the linear transduction of electro-mechanical than (electro-mechanical linear transducer ratio), and its unit is newton/volt or coulomb/rice.
Though being the coupling capacitance of utilizing the user that Trackpad is caused, the principle of capacitive touch control plate learns the contact position of user on Trackpad, but when on circuit, realizing, actual detected be voltage signal, relational expression via Q=C * V converts the voltage signal that records to capacitance again, to learn the capacitance variations on the Trackpad.The present invention utilizes the characteristic of piezoelectric, designs the pointer of using for the operating capacitance touch plate.
Fig. 2 is the sectional view according to pointer embodiment of the present invention, and the nib 100 of pointer 10 is used as the pressure conducting stratum, makes with hard conductive material, can conducting pressure and electric charge.Piezoelectric element 102 is arranged between support member 104 and the nib 100, and support member 104 is supported piezoelectric element 102, piezoelectric element 102 contact nibs 100.When pointer 10 touch mode capacitive Trackpads 20 surperficial, nib 100 transmits pressure and causes piezoelectric element 102 to produce deformation, and piezoelectric element 102 produces voltage Vx superpositions on trace 22, and capacitor C x represents the equivalent capacity of trace 22.During capacitance variations on detecting trace 22, detecting device 24 can be considered as ground connection with the current potential on the trace 22, but the voltage Vx that piezoelectric element 102 produces is less than zero, and the voltage change that makes detecting device 24 sense on the trace 22 increases.As previously mentioned, Q=C * V, voltage change increase the Q value that makes detector end see and promote, and its effect is equal to capacitance change and increases, and has therefore increased the sensitivity of 24 pairs of capacitive touch control plates 20 of detecting device, makes sensing more sensitive.Support member 104 is a conductor, and lead 106 connects ground plane 108, sees through the positive wire ground connection that human body is used as battery eliminator, to discharge the electric charge that piezoelectric element 102 pressurizeds produce.
More than be stated as the purpose of illustrating for what preferred embodiment of the present invention was done, accurately be disclosed form and be not intended to limit the present invention, based on above instruction or to make an amendment or change from embodiments of the invention study be possible, embodiment is for explaining orally principle of the present invention and allow those skilled in the art of the present technique utilize the present invention to select in practical application with various embodiment and narrate, and technological thought attempt of the present invention is decided by claim and impartial variation the thereof.
Claims (9)
1. a pointer that is used for capacitive touch control plate is characterized in that, described pointer comprises:
The pressure conducting stratum when being pressed on described capacitive touch control plate under described pointer, transmits the pressure of described contact point;
Piezoelectric element contacts described pressure conducting stratum, and the pressure that receives its transmission is to produce voltage; And
Support member is supported described piezoelectric element.
2. pointer as claimed in claim 1 is characterized in that, described pressure conducting stratum is a conductor.
3. pointer as claimed in claim 1 is characterized in that, described pressure conducting stratum is an insulator.
4. pointer as claimed in claim 1 is characterized in that, described support member is a conductor.
5. pointer as claimed in claim 4 is characterized in that, described pointer more comprises:
Lead connects described support member;
Ground plane connects described lead; And
Insulation wall connects described ground plane and described support member, forms electric capacity with described support member and described ground plane, with described piezoelectric element ground connection.
6. pointer as claimed in claim 1 is characterized in that, the voltage that described piezoelectric element produces changes the earthing potential of described capacitive touch control plate at described contact point.
7. pointer as claimed in claim 6 is characterized in that, the voltage that described piezoelectric element produces is negative voltage.
8. the contact detecting method of a capacitive touch control plate is characterized in that, described method comprises:
A contact point on the described capacitive touch control plate is exerted pressure;
Convert described pressure to a voltage, thereby change the earthing potential of described contact point; And
Detect the change in voltage on the described capacitive touch control plate.
9. detection method as claimed in claim 8 is characterized in that, the described step that converts described pressure to described voltage comprises piezoelectric element is applied described pressure to produce described voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910005982A CN101788858A (en) | 2009-01-22 | 2009-01-22 | Contact detection method of capacitive touchpad and stylus thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910005982A CN101788858A (en) | 2009-01-22 | 2009-01-22 | Contact detection method of capacitive touchpad and stylus thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101788858A true CN101788858A (en) | 2010-07-28 |
Family
ID=42532094
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200910005982A Pending CN101788858A (en) | 2009-01-22 | 2009-01-22 | Contact detection method of capacitive touchpad and stylus thereof |
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| Country | Link |
|---|---|
| CN (1) | CN101788858A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102221911A (en) * | 2011-06-24 | 2011-10-19 | 江汉大学 | Touch electronic pen |
| CN102364412A (en) * | 2011-10-26 | 2012-02-29 | 苏州瀚瑞微电子有限公司 | Circuit structure of capacitive touch control pen |
-
2009
- 2009-01-22 CN CN200910005982A patent/CN101788858A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102221911A (en) * | 2011-06-24 | 2011-10-19 | 江汉大学 | Touch electronic pen |
| CN102221911B (en) * | 2011-06-24 | 2013-11-20 | 江汉大学 | Touch electronic pen |
| CN102364412A (en) * | 2011-10-26 | 2012-02-29 | 苏州瀚瑞微电子有限公司 | Circuit structure of capacitive touch control pen |
| CN102364412B (en) * | 2011-10-26 | 2014-03-12 | 苏州瀚瑞微电子有限公司 | Circuit structure of capacitive touch control pen |
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| PB01 | Publication | ||
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| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Open date: 20100728 |