CN101846712A - ITO (Indium Tin Oxide) electrical characteristic detecting method and detecting system of capacitance type touch screen - Google Patents

Abstract

The invention relates to an ITO (Indium Tin Oxide) electrical characteristic detecting system of a capacitance type multipoint touch screen, which comprises an inductive electrode array circuit board, a sine wave phase measuring circuit and a sine wave signal control and data processing circuit, wherein the inductive electrode array circuit board is used for carrying a detected touch screen and respectively transmitting sine waves to all ITO circuit layers of the touch screen during the detection, the sine wave phase measuring circuit is used for measuring a phase difference between an input signal and an inducing signal; the capacitance field distributing condition between all ITO circuit layers and an inductive electrode and between two adjacent ITO circuit layer is obtained by adjusting the output of sine wave frequency; and that whether the electrical characteristic of an ITO line and a silver lead is favorable or not can be judged according to the capacitance field distribution, thereby realizing further detection of the yield of the touch screen and having greater popularization and application value.

Description

Capacitive touch screen ITO electrical specification detection method and detection system

Technical field

The present invention relates to the detection of capacitive touch screen, the ITO electrical specification that relates in particular to touch-screen detects to judge that this product is non-defective unit or defective products.

Background technology

Touch-screen is because it is sturdy and durable, reaction velocity fast, save the space, be easy to plurality of advantages such as interchange is more and more used.Type of touch screens mainly contains resistive touch screen, capacitive touch screen at present, and wherein making the transparent thin-film material that forms by ITO (indium tin oxide or title oxide indium tin) is the critical material of making the condenser type multi-point touch panel.This kind capacitive touch screen is formed by two-layer at least ito thin film pressing; shown in Figure 1 is a kind of sectional view of capacitive touch screen; its outermost layer be two-layer protective seam 30,30 '; be positioned at two protective seams 30,30 ' inboard and be two ITO circuit layers 20,20 '; two ITO circuit layers 20,20 ' between be provided with separation layer 10; every layer of ITO circuit layer (as shown in Figure 2) mainly is provided with ITO interface 201, be the ITO electrode 203 that strip distributes and be connected ITO electrode 203 and ITO interface 201 between silver-colored lead 202.Before the touch-screen manufacturing is dispatched from the factory, need test its electrical specification, be non-defective unit or defective products with the senses touch screen, thereby avoid the defective products use that puts goods on the market.The existing integrality of the detection of ITO capacitive touch screen mainly being judged the ITO circuit by the resistance value between the detection ITO circuit, the unfavorable condition that is detected comprises the short circuit between a place or many places silver line, short circuit between the ITO circuit, the electric leakage between circuit and the deviation of about beam impedance etc., when above-mentioned sight not occurring, judge that then this touch-screen product is a non-defective unit, in fact, for this kind touch-screen, also can exist silver-colored line to break or ITO circuit phenomenon such as break, the appearance of these phenomenons also will make touch-screen produce fatal defective, situation can not be detected and existing detection system and detection method are broken to silver-colored line or the ITO circuit breaks etc., and the application just is being based on this problem and the design carried out.

Summary of the invention

Thereby the present invention seeks to provides a kind of further senses touch of capacitance field distribution that can detect the condenser type multi-point touch panel to shield the detection method of yield and the detection system of this method of employing in order to overcome the deficiencies in the prior art.

For achieving the above object, the technical solution adopted in the present invention is: a kind of capacitive touch screen ITO electrical specification detection method, described capacitive touch screen comprises two-layer at least ITO circuit layer, be provided with separation layer between the adjacent ITO circuit layer, every layer of ITO circuit layer comprise the ITO interface, be arranged on many ITO electrodes on the ITO interface, be connected the silver-colored lead between ITO interface and every the ITO electrode, and this method comprises the steps:

(a), the capable induction electrode array of a M*N is set, measured capacitance formula touch-screen is placed on this induction electrode array, and make that the tested point position is corresponding one by one on induction electrode array and the capacitive touch screen, can equivalence be the circuit of an inductance capacitance of an inductive reactance series connection all between the ITO electrode of every layer of ITO circuit layer and corresponding each induction electrode then;

(b), with one detection inductance one end of inductance value be connected with the ITO interface of ground floor ITO circuit layer, the other end that detects inductance is defined as signal input part; Continuous with detection resistance one end of a known value again with corresponding induction electrode, detect resistance other end ground connection, detection resistance one end that is connected with induction electrode is defined as the test side, constitutes a rlc circuit between inductance, inductive reactance, inductance capacitance and the detection resistance thereby detect;

(c), to the sine wave signal of a fixed frequency of above-mentioned signal input part input, then produce identical with the input sine wave frequency, as to have a certain phase difference sine wave in described test side;

(d), by measuring the phase difference between signal input part and the test side, regulate the frequency of input sine wave, make that the sine wave of input and the sinusoidal wave phase difference of test side are 0, can calculate the inductance capacitance between corresponding ITO electrode place and the induction electrode, choose a phase difference and be not equal to 0 test result, can calculate the induced electricity resistance;

(e), respectively all ITO electrodes of ground floor ITO circuit layer are measured, according to step (b, c, d) thus obtain two-dimentional inductive reactance array and two-dimentional inductance capacitance value matrix corresponding to ground floor ITO circuit layer;

(f), can judge whether the ITO electrode structure of described ground floor ITO circuit layer exists fracture, break or the defective of electrical structure such as short circuit according to the two-dimentional inductive reactance array that records in the step (e); According to the two-dimentional inductance capacitance value matrix that records can judge whether have that distribution of material is inhomogeneous around the ITO electrode of ground floor ITO circuit layer, bad defectives such as bubble or circuit scratch;

(g), according to above-mentioned steps (b, c, d) all ITO electrodes of other layer ITO circuit layer are measured, thereby can obtain the two-dimentional inductive reactance value matrix and the two-dimentional inductance capacitance value matrix of this layer ITO circuit layer, thereby can judge the quality of corresponding ITO circuit layer;

(h), the capacitance matrix between the adjacent two ITO circuit layers of two-dimentional inductive reactance matrix of the corresponding ITO circuit layer that records according to step (f, g) with two-dimentional inductance capacitance matrix computations, thereby can judge whether even the capacitance field between the adjacent two ITO circuit layers distributes.

The present invention also provides a kind of capacitive touch screen ITO electrical specification detection system, and it comprises:

Induction electrode array circuit plate, it comprises M*N induction electrode being the capable N row of M is set, described touch-screen is arranged on the induction electrode array circuit plate, and the position of measured point is corresponding one by one in vertical direction with induction electrode on the circuit board on the touch-screen;

The sine wave phase measurement circuit, it comprises that the sine wave that input end is connected with the induction electrode of described induction electrode array circuit plate changes circuit and square-wave, changes the phase differential commentaries on classics voltage circuit that the circuit and square-wave output terminal is connected with sine wave;

Sine wave signal control and data processing circuit, it comprises ITO interface and the sinusoidal wave sine wave generating circuit that circuit and square-wave is electrically connected, the control module that is connected with described phase differential commentaries on classics voltage circuit output end of changeing on corresponding with the capacitive touch screen respectively ITO circuit layer of output terminal, and described control module and sine wave generating circuit be control linkage mutually;

During detection, sine wave signal control and data processing circuit change circuit and square-wave input sine wave signal by its sine wave generating circuit to the ITO of tested touch-screen interface and sine wave, described phase differential changes the voltage circuit will be needed the input signal that induction electrode measured of measuring position and all phase differential between the induced signal to convert voltage signal to export control module to, described control module is adjusted the sine wave freuqency of the output of sine wave generating circuit, thereby record two-dimentional inductance capacitance and resistance value between each ITO circuit layer and the adjacent ITO circuit layer, and carry out the judgement of tested touch-screen quality according to preset standard capacitance resistance value.

Because the employing of technique scheme, the present invention compared with prior art has the following advantages: the detection system that adopts detection method of the present invention, on the basis that combined impedance detects, the detection that increase distributes to the touch-screen capacitance field, thereby the integrality that the electrical specification of improving ITO circuit and silver-colored lead more detects has bigger application value.

Description of drawings

Accompanying drawing 1 is a capacitive touch screen cross section structure synoptic diagram;

Accompanying drawing 2 is the every ITO circuit layer of a capacitive touch screen structural representation;

Accompanying drawing 3 is the position view of touch-screen of the present invention and induction electrode array;

Accompanying drawing 4 is the equivalent circuit diagram of ITO electrode and induction electrode;

Accompanying drawing 5 is for the present invention is based on the rlc circuit figure that ITO circuit layer equivalent electrical circuit makes up;

Accompanying drawing 6 is capacitive touch screen ITO electrical specification detection system block diagram of the present invention;

Accompanying drawing 7 is the induction electrode array circuit of the present invention composition that hardens;

Accompanying drawing 8 is sine wave phase measurement circuit multiselect one circuit diagram of the present invention;

Accompanying drawing 9 changes the circuit and square-wave schematic diagram for the present invention is sinusoidal wave;

Accompanying drawing 10 changes the voltage circuit theory diagrams for phase differential of the present invention;

Accompanying drawing 11 is a phase difference detection oscillogram in the accompanying drawing 10;

Accompanying drawing 12 is sine wave signal control of the present invention and data processing circuit schematic diagram;

Wherein: 1, sensing electrode array circuit plate; 11, substrate; 12, induction electrode; 13, circuit; 2, sine wave phase measurement circuit; 21, the sinusoidal wave circuit and square-wave of changeing; 22, phase differential changes the voltage circuit; 221, counter; 222, phase differential is judged and computing unit; 223, D/A change-over circuit; 23, multiselect one circuit; 3, sine wave signal control and data processing circuit; 32, control module; 31, sine wave generating circuit; 33, frequency/phase difference record cell; 34, capacitance resistance value computing unit; 35, A/D change-over circuit; 10, separation layer; 20, ITO circuit layer; 20 ', the ITO circuit layer; 30, protective seam; 30 ', protective seam;

Embodiment

Below in conjunction with accompanying drawing the preferred embodiment of the present invention is elaborated:

Before employing the inventive method detects touch-screen, can at first adopt existing impedance detection method that touch-screen is detected, when the touch-screen that adopts the resistance value method to detect occurs not needing to adopt the inventive method just to assert directly that this touch-screen is a defective products when bad again; When bad problem does not appear in the touch-screen that adopts existing resistance value method to detect, can further adopt detection method of the present invention that the capacitance field distribution situation of touch-screen is further detected, to be example with touch-screen shown in Figure 1 below, at first condenser type multi-point touch panel ITO electrical specification detection method implementation procedure of the present invention be described:

Step 1, the capable N row of M induction electrode is set forms the induction electrode array, measured capacitance formula touch-screen is placed on this induction electrode array, as shown in Figure 3, and make that the tested point position is perpendicular corresponding with induction electrode 12 on the capacitive touch screen, thereby can equivalence between the ITO electrode 203 of equivalent layer ITO circuit layer and the induction electrode 12 become the connect circuit of a capacitor C s of a resistance R, as shown in Figure 4, in the present invention, resistance R is called inductive reactance, capacitor C s is called inductance capacitance, and this inductive reactance R and inductance capacitance Cs are the capacitance resistance of required measurement;

Step 2, as shown in Figure 5, with the detection inductance L 1 of a known inductance value, the one end links to each other with the ITO interface of corresponding ITO circuit layer, and the other end is signal input part TP1; Use the detection resistance R 1 of a known resistance again, one end and induction electrode are connected to test side TP2, and an end links to each other with 0 current potential; Thereby entire circuit constitutes a rlc circuit; To the sine wave signal of a fixed frequency of signal input part TP1 input, then test side TP2 can produce one identical with the input sine wave frequency, phase difference is the sine wave of φ;

According to the Ohm law that contains source circuit, can draw the voltage balance equation of Fig. 5 circuit:

${\mathrm{\&epsiv;}}_0\sin \mathrm{\&omega;t}=L_1\frac{d^2\mathrm{<figure-callout\; id="2"\; label="q\; d\; t"\; filenames="HSA00000049672600023.png"\; state="\{\{state\}\}">q</figure-callout>}}{d{t}^{}}+R\frac{\mathrm{dq}}{\mathrm{dt}}+\frac{q}{\mathrm{Cs}}+{\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="HSA00000049672600031.png,HSA00000049672600032.png"\; state="\{\{state\}\}">R</figure-callout>}}_1\frac{\mathrm{dq}}{\mathrm{dt}}$ (formula 1)

(ε wherein ₀Be the sine wave signal voltage magnitude)

Formula 1 is got the differential of time t, and Substitution,

${\mathrm{\&epsiv;}}_0\mathrm{\&omega;}\cos \mathrm{\&omega;t}=L_1\frac{d^2\mathrm{<figure-callout\; id="2"\; label="I\; dt"\; filenames="HSA00000049672600023.png"\; state="\{\{state\}\}">I</figure-callout>}}{{\mathrm{dt}}^{}}+R\frac{\mathrm{dI}}{\mathrm{dt}}+\frac{I}{\mathrm{Cs}}+{\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="HSA00000049672600031.png,HSA00000049672600032.png"\; state="\{\{state\}\}">R</figure-callout>}}_1\frac{\mathrm{dI}}{\mathrm{dt}}$ (formula 2)

Separating of the above-mentioned differential equation can be write under steady state (SS)

I=I ₀Sin (ω t-φ) (formula 3)

In the formula 3,

${\mathrm{<figure-callout\; id="0"\; label="I"\; filenames="HSA00000049672600021.png"\; state="\{\{state\}\}">I</figure-callout>}}_0=\frac{{\mathrm{\&epsiv;}}_0}{Z}=\frac{{\mathrm{\&epsiv;}}_0}{\sqrt{{(R+R_1)}^2+{({\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HSA00000049672600031.png,HSA00000049672600032.png"\; state="\{\{state\}\}">L</figure-callout>}}_1\mathrm{\&omega;}-\frac{1}{\mathrm{Cs\&omega;}})}^2}}$ (formula 4)

$\tan \mathrm{\&phi;}=\frac{{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HSA00000049672600031.png,HSA00000049672600032.png"\; state="\{\{state\}\}">L</figure-callout>}}_1\mathrm{\&omega;}-\frac{1}{\mathrm{Cs\&omega;}}}{R+R_1}$ (formula 5)

By formula 3,4,5 as can be known when the steady state (SS), the frequency of electric current Identical with the frequency of the sine wave signal of importing, current amplitude I ₀Constant value is arranged, the phase differential of φ is arranged between electric current and the input signal.When

The time phase difference φ=0, promptly

${\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="HSA00000049672600021.png"\; state="\{\{state\}\}">f</figure-callout>}}_0=\frac{\mathrm{\&omega;}}{2\mathrm{\&pi;}}=\frac{1}{2\mathrm{\&pi;}}\sqrt{\frac{1}{{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HSA00000049672600031.png,HSA00000049672600032.png"\; state="\{\{state\}\}">L</figure-callout>}}_1\mathrm{Cs}}}$ (formula 6)

For the signal U on the check point TP2 _R1=IR ₁=I ₀Sin (ω t-φ) R ₁So the detection signal of check point TP2 is that frequency is identical with the pass of the input signal of TP1, has phase difference φ;

Step 3 according to the judgement of function monotonicity, has only a frequency to make phase difference φ=0, and phase difference with frequency (0 ,+∞) scope inherence

Dull increasing in interval; By measuring the phase difference between TP1 and the TP2, the frequency of regulating input sine wave makes phase difference φ=0 of the measurement sine wave of the input sine wave of signal input part TP1 and test side TP2, promptly obtains f ₀, substitution formula 6 calculates Cs, chooses a phase difference and is not equal to 0 test result, with φ, Cs, the above-mentioned formula 5 of ω substitution, can calculate resistance value R.

Further, formula 5 can be rewritten into

$\mathrm{\&phi;}=\arctan \left(\frac{{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HSA00000049672600031.png,HSA00000049672600032.png"\; state="\{\{state\}\}">L</figure-callout>}}_1\mathrm{\&omega;}-\frac{1}{\mathrm{Cs\&omega;}}}{R+R_1}\right)$ (formula 7)

ω (0 ,+∞) interval in value, to formula 6 both sides differentiates,

${\mathrm{\&phi;}}^{\&prime;}=\frac{1}{1+{\left(\frac{{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HSA00000049672600031.png,HSA00000049672600032.png"\; state="\{\{state\}\}">L</figure-callout>}}_1\mathrm{\&omega;}-\frac{1}{\mathrm{Cs\&omega;}}}{R+R_1}\right)}^2}$ (formula 8)

By formula 7 φ '＞0 as can be known, according to the criterion of function monotonicity, ω (0 ,+∞) interval in value, phase difference φ is dull to be increased, scope is

Have only a frequency values corresponding with it for φ=0.

Step 4: respectively all ITO electrodes of ITO circuit layer 20 shown in Figure 1 are measured by step 1,2,3, can obtain the two-dimentional resistance value matrix R of two correspondences and this ITO circuit layer 20 _t[m, n] and two-dimentional capacitance Matrix C _t[m, n];

Step 5: according to the two-dimentional resistance value matrix R that measures in the step 4 _t[m, n] can judge whether the ITO electrode structure of this ITO circuit layer 20 exists fracture, break or the defective of electrical structure such as short circuit; According to the two-dimentional capacitance Matrix C that measures in the step 4 _t[m, n] can judge whether have that distribution of material is inhomogeneous around the ITO electrode of this ITO circuit layer 20, defectives such as bubble or the scratch of ITO circuit are bad;

Step 6: by step 1,2,3 respectively to another ITO circuit layer 20 ' all ITO electrodes measure, can obtain one group of corresponding and this ITO circuit layer 20 ' two-dimentional resistance value matrix R _b[m, n] and two-dimentional capacitance Matrix C _b[m, n]; According to the two-dimentional resistance value matrix R that measures _b[m, n] can judge this ITO circuit layer 20 ' the ITO electrode structure whether have fracture, break or the defective of electrical structure such as short circuit; According to the two-dimentional capacitance Matrix C that measures _b[m, n], can judge this ITO circuit layer 20 ' the ITO electrode around whether have that distribution of material is inhomogeneous, defectives such as bubble or the scratch of ITO circuit are bad;

Step 7: the two-dimentional capacitance Matrix C that obtains in the step 4 _tThe two-dimentional capacitance Matrix C that obtains in [m, n] and the step 6 _b[m, n] is respectively the two-dimentional capacitance matrix of two ITO circuit layers 20,20 ' form corresponding to the capacitance of induction electrode array each point.According to following formula 9, the calculating through to two each correspondence positions of matrix can obtain a two-dimensional matrix C about capacitance between two ITO circuit layers _P[m, n] is to C _P[m, n] value of each point and the position at the interior place of its position capacitive touch screen, thereby distributing, the capacitance field that can draw measured capacitance formula touch-screen inside whether judges uniformly, also just whether exist silver-colored line to break and whether the ITO circuit breaks and judge, thereby guarantee to detect more accurate touch-screen.

$C_p=\frac{C_t{C}_b}{C_b-C_t}$ (formula 9)

Above condenser type multi-point touch panel ITO electrical specification detection method is illustrated, still the detection system that adopts this method to realize is described below in conjunction with touch-screen shown in Figure 1:

Detection system of the present invention mainly is made up of three parts: sensing electrode array circuit plate 1, sine wave phase measurement circuit 2, sine wave signal control and data processing circuit 3 three parts constitute, and as shown in Figure 6, below each circuit part are elaborated:

As shown in Figure 7, described sensing electrode array circuit plate 1 main by substrate 11, be arranged on the induction electrode 12 that is the capable N row of M on the substrate 11 and the circuit 13 that is connected with each induction electrode 12 is formed, the shape of induction electrode can be rectangle, triangle or circle, the M of induction electrode concrete numbers capable and the N row can be set according to the size of measured capacitance formula touch-screen, inner ITO electrode structure;

In when test, measured capacitance formula touch-screen is positioned on the sensing electrode array circuit plate 1, and the position, measured point of capacitive touch screen is corresponding one by one in vertical direction with induction electrode on the circuit board, as shown in Figure 3; Each induction electrode is connected to described sine wave phase measurement circuit 2 respectively.

Because the size difference of the capacitive touch screen that is measured, the number of electrodes of sensing electrode array are also different, therefore, in the present embodiment, the sine wave phase measurement circuit is designed to maximum 16 individual modules that measure passage; The sine wave phase measurement circuit just independently measures module by N to be formed, and can survey 16xN induction electrode at most; Each measure module by 16 passages select 1 circuit 23, sinusoidal wave change circuit and square-wave 21, and phase differential change voltage circuit 22 and constitute.Signal processing is as follows between each circuit:

At first, sine wave phase measurement circuit 1 is selected 1 circuit 23 by 16 passages from 16 measurement passages of induction electrode array circuit plate 1 input, as shown in Figure 8, select an input signal S1;

Then, sine wave phase measurement circuit 1 obtains sinusoidal wave comparison signal S2 from described sine wave signal control and data processing circuit 3 input signals; The signal S1 and the S2 difference input sine wave that obtain in the last step are changeed circuit and square-wave 21, produce 2 TTL square-wave signal D1 and D2, as shown in Figure 9;

At last, with square-wave signal D1 and the D2 that obtains, send into phase differential and change voltage circuit 22, see Figure 10, phase differential changes voltage circuit 22 and comprises the counter 221 that is electrically connected successively, phase differential is judged and counting circuit 222, D/A change-over circuit 223, counter 221 is a trigger pip with square-wave signal D2 rising edge, begin counting with certain count frequency F, F must when detecting the rising edge of square-wave signal D1, obtain count value N1 greater than 360 times of square-wave signal D2 frequency, when detecting the next rising edge of square-wave signal D2, counting stops, and obtains count value N2, referring to shown in Figure 11;

According to formula 7 as can be known, all phase differential scopes between input signal and the sensing signal are

Therefore, when

The time, sensing signal hysteresis input signal, all phase differential When The time, the leading input signal of sensing signal, all phase differential

According to the phase difference of following formula 10 with input signal and sensing signal, convert the voltage signal V1 of 1-4V to by the D/A change-over circuit, the V1 signal is sent to sine wave signal control and data processing circuit 3.

${\mathrm{<figure-callout\; id="1"\; label="V"\; filenames="HSA00000049672600031.png,HSA00000049672600032.png"\; state="\{\{state\}\}">V</figure-callout>}}_1=\left\{\begin{array}{cc}\frac{N_1}{{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HSA00000049672600023.png"\; state="\{\{state\}\}">N</figure-callout>}}_2}\&times;6+2.5& (\frac{N_1}{{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HSA00000049672600023.png"\; state="\{\{state\}\}">N</figure-callout>}}_2}<\frac{1}{4})\\ -\frac{N_2-N_1}{{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HSA00000049672600023.png"\; state="\{\{state\}\}">N</figure-callout>}}_2}\&times;6+2.5& (\frac{N_1}{{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HSA00000049672600023.png"\; state="\{\{state\}\}">N</figure-callout>}}_2}>\frac{3}{4})\end{array}\right.$ (formula 10)

Described sine wave signal control and data processing circuit 3 mainly comprise the sine wave generating circuit 31 that is used to produce sine wave, the control module 32 that is used for core control, frequency/phase difference record cell 33, capacitance resistance value computing unit 34, and A/D change-over circuit 35, it also is provided with and is used for interface that is connected with sine wave phase measurement circuit 2 and the interface that is complementary and is connected with tested touch-screen ITO circuit layer interface simultaneously, as shown in figure 12, when measuring, described sine wave signal control and data processing circuit 3 are connected with sine wave phase measurement circuit 2 and tested touch-screen by the corresponding interface, by the sine wave signal S2 of sine wave generating circuit 31 generation adjustable frequencies, send into the inside ITO electrode of sine wave phase measurement circuit 2 and tested touch-screen ITO circuit layer respectively;

Voltage signal after the conversion of described control module 32 reception sine wave phase measurement circuit 2 outputs, be sent to A/D change-over circuit 35 as feedback element, so that sine wave generating circuit 31 is adjusted the frequency of sine wave output, making sine wave signal S1 and S2 week phase differential is 0, and the frequency that records is sent to frequency record unit 33.

Frequency/all phase differential record cells 33 will record frequency and all phase differential be kept at corresponding matrix F of induction electrode array position and φ in, its at the middle and upper levels the result that records of ITO circuit layer 20 be Ft[m, n] and φ t[m, n], the result of the ITO of lower floor circuit layer 20 ' record is Fb[m, n] and φ b[m, n].

Capacitance resistance value record cell 34 is according to the matrix F and the φ that preserve in frequency/all phase differential record cells 33, according to above-mentioned formula 5, calculates upper strata ITO circuit layer 20 and the ITO of lower floor circuit layer 20 ' corresponding to the capacitance Matrix C of induction electrode array each point _t[m, n], C _b[m, n] and resistance value matrix R _t[m, n], R _b[m, n], according to formula 9, through to the calculating of two each correspondence positions of matrix, obtain one about upper strata ITO circuit layer 20 and the ITO of lower floor circuit layer 20 ' between the two-dimensional matrix C of capacitance _F[m, n]; With above-mentioned five Matrix C _t[m, n], C _b[m, n], R _t[m, n], R _b[m, n], C _F[m, n] compares with the standard value of presetting, thereby can judge that test product is defective products or non-defective unit.

Detection system of the present invention increases the detection that the touch-screen capacitance field is distributed on the basis that combined impedance detects, thereby improves the integrality of the electrical specification detection of ITO circuit and silver-colored lead more, has bigger application value.

The foregoing description only is explanation technical conceive of the present invention and characteristics; its purpose is to allow the personage who is familiar with this technology can understand content of the present invention and enforcement according to this; can not limit protection scope of the present invention with this; all equivalences that spirit is done according to the present invention change or modify, and all should be encompassed within protection scope of the present invention.

Claims (7)

1. capacitive touch screen ITO electrical specification detection method, described capacitive touch screen comprises two-layer at least ITO circuit layer, be provided with separation layer between the adjacent ITO circuit layer, every layer of ITO circuit layer comprise the ITO interface, be arranged on many ITO electrodes on the ITO interface, be connected the silver-colored lead between ITO interface and every the ITO electrode, and it is characterized in that: this method comprises the steps:

(a), the capable induction electrode array of a M*N is set, measured capacitance formula touch-screen is placed on this induction electrode array, and make that the tested point position is corresponding one by one on induction electrode array and the capacitive touch screen, can equivalence be an inductive reactance all between the ITO electrode of every layer of ITO circuit layer and corresponding each induction electrode then

(R) circuit of an inductance capacitance of series connection (Cs);

(b), with one detection inductance (L1) end of inductance value be connected with the ITO interface of ground floor ITO circuit layer, the other end that detects inductance (L1) is defined as signal input part (TP1); Use detection resistance (R1) end of a known value continuous again with corresponding induction electrode, detect resistance (R1) other end ground connection, detection resistance one end that is connected with induction electrode is defined as test side (TP2), constitutes a rlc circuit between the resistance (R1) thereby detect inductance (L1), inductive reactance (R), inductance capacitance (Cs) and detect;

(c), to the sine wave signal of a fixed frequency of above-mentioned signal input part (TP1) input, then produce identical with the input sine wave frequency, as to have a certain phase difference sine wave at described test side (TP2);

(d), by measuring the phase difference between signal input part and the test side, regulate the frequency of input sine wave, make that the sine wave of input and the sinusoidal wave phase difference of test side are 0, can calculate the inductance capacitance (Cs) between corresponding ITO electrode place and the induction electrode, choose a phase difference and be not equal to 0 test result, can calculate induced electricity resistance (R);

(e), respectively all ITO electrodes of ground floor ITO circuit layer are measured, according to step (b, c, d) thus obtain two-dimentional inductive reactance array (R corresponding to ground floor ITO circuit layer _t[m, n]) and two-dimentional inductance capacitance value matrix (C _t[m, n]);

(f), according to the two-dimentional inductive reactance array (R that records in the step (e) _t[m, n]) whether the ITO electrode structure that can judge described ground floor ITO circuit layer exist fracture, break or the defective of electrical structure such as short circuit; According to the two-dimentional inductance capacitance value matrix (C that records _t[m, n]) can judge whether have that distribution of material is inhomogeneous around the ITO electrode of ground floor ITO circuit layer, bad defectives such as bubble or circuit scratch;

(g), all ITO electrodes of other layer ITO circuit layer are measured, according to above-mentioned steps (b, c, d) thus can obtain the two-dimentional inductive reactance value matrix (R of this layer ITO circuit layer _b[m, n]) and two-dimentional inductance capacitance value matrix (C _b[m, n]), thus can judge the quality of corresponding ITO circuit layer;

(h), the capacitance matrix (C between the adjacent two ITO circuit layers of two-dimentional inductive reactance matrix of the corresponding ITO circuit layer that records according to step (f), (g) with two-dimentional inductance capacitance matrix computations _p[m, n]), thus can judge whether even the capacitance field between the adjacent two ITO circuit layers distributes.

2. one kind is adopted the described detection method of claim 1 to carry out capacitive touch screen ITO electrical specification detection system, and it is characterized in that: it comprises:

Induction electrode array circuit plate (1), it comprises that setting is M*N induction electrode of the capable N row of M, described touch-screen is arranged on the induction electrode array circuit plate (1), and the position of measured point is corresponding one by one in vertical direction with induction electrode on the circuit board on the touch-screen;

Sine wave phase measurement circuit (2), it comprises that the sine wave that input end is connected with the induction electrode of described induction electrode array circuit plate (1) changes circuit and square-wave (21), changes the phase differential commentaries on classics voltage circuit (22) that circuit and square-wave (21) output terminal is connected with sine wave;

Sine wave signal control and data processing circuit (3), it comprises ITO interface and the sinusoidal wave sine wave generating circuit (31) that circuit and square-wave (21) is electrically connected, the control module (32) that is connected with described phase differential commentaries on classics voltage circuit (22) output terminal of changeing on corresponding with the capacitive touch screen respectively ITO circuit layer of output terminal, and described control module (32) and sine wave generating circuit (31) be control linkage mutually;

During detection, sine wave signal control and data processing circuit (3) change circuit and square-wave (21) input sine wave signal by its sine wave generating circuit (31) to the ITO of tested touch-screen interface and sine wave, described phase differential changes voltage circuit (22) will be needed the input signal that induction electrode measured of measuring position and all phase differential between the induced signal to convert voltage signal to export control module (32) to, described control module (32) is adjusted the sine wave freuqency of the output of sine wave generating circuit (31), thereby record two-dimentional inductance capacitance and resistance value between each ITO circuit layer and the adjacent ITO circuit layer, and carry out the judgement of tested touch-screen quality according to preset standard capacitance resistance value.

3. capacitive touch screen ITO electrical specification detection system according to claim 2, it is characterized in that: each induction electrode on the described induction electrode array circuit plate (1) is shaped as rectangle, triangle or circle.

4. capacitive touch screen ITO electrical specification detection system according to claim 2, it is characterized in that: described sine wave phase measurement circuit (2) independently measures module by N and forms, each measures module and has a plurality of measurement passages, and the multiple signals of exporting from the induction electrode array circuit input to sinusoidal wave the commentaries on classics the circuit and square-wave (21) by multiselect one circuit.

5. according to claim 2 or 4 described capacitive touch screen ITO electrical specification detection systems, it is characterized in that: described phase differential changes voltage circuit (22) and comprises the counter (221) that is electrically connected successively, phase differential is judged and counting circuit (222), D/A change-over circuit (223), detection signal and input signal input to counter (221) after being converted to square wave, described counter (221) is a trigger pip with the input signal rising edge after changing, begin counting with count frequency much larger than incoming frequency, when detecting the rising edge of detection signal, obtain count value N1, when detecting the next rising edge of input signal, counting stops, obtain count value N2, according to two count value N1, the relation of N2 calculates the phase difference of input signal and detection signal, and converts voltage signal to by D/A change-over circuit (223) and export sine wave signal control and data processing circuit (3) to.

6. capacitive touch screen ITO electrical specification detection system according to claim 5, it is characterized in that: described count frequency is greater than more than 360 times of input sine wave signal frequency.

7. capacitive touch screen ITO electrical specification detection system according to claim 2, it is characterized in that: described sine wave signal control and data processing circuit (3) also comprise frequency/phase difference record cell (33), capacitance resistance value computing unit (34), described frequency/phase difference record cell (33) with the frequency that records and phase difference be kept at the corresponding matrix of induction electrode array position in, capacitance resistance value computing unit (34) is according to the matrix computations capacitance resistance matrix of preserving in frequency/phase difference record cell (33).

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