TWI251782B - Control method of capacitive type touch-controlled panel and its apparatus - Google Patents

Abstract

The present invention is related to a control method of capacitive type touch-controlled panel and its apparatus. The method comprises inputting AC signals of constant voltage to the touch-controlled panel and then receiving its current signals; sampling and amplifying its read value; determining whether the touch-controlled panel is touched based on whether the value is larger than a threshold or not; and if it is touched, obtaining the difference of the read values before touch and after touch for being converted into a coordinate of the touched position. Accordingly, it is able to effectively increase the accuracy of computed coordinates.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a device for controlling a capacitive touch panel, and more particularly to a method for controlling a capacitive touch panel capable of greatly improving the accuracy of measurement coordinates. Device. [Prior Art] Due to the rapid development of computer technology, many home appliances, daily necessities, industrial equipment and even financial facilities have been digitally completed, and so-called touch screens (T〇uthscreen) are widely used in the operation interface, for example. Automatic teller machine (ATM), ticket vending machine, navigation system, personal digital assistant (pj) A), etc., can be selected by direct contact with the button pattern (IC〇N) of the screen, or by dragging with the touch track The function of writing or drawing, in fact, the function of the touch screen is not limited to this, so its application field is becoming more and more extensive, and it also has huge business opportunities, and provides a powerful incentive for the industry to develop and improve existing technologies. Therefore, this article uses the coordinate measurement accuracy of the capacitive touch screen (board) as a review and further improvement to help improve competitiveness. As shown in the second figure, the basic structure of a capacitive touch panel is disclosed, which is mainly provided on a transparent and uniformly flat substrate (8 〇) with a conductive layer (81) (82) and conductively connected up and down. An insulating isolation layer (83) (8 4 ) is disposed on opposite sides of the layer (81) (82). 6 When the opposite end of the upper conductive layer (8 1 ) is loaded with the AC signal of the solid voltage, and the lower conductive (82) is connected to the fixed straight 1251782 current potential or ground. At this time, the upper conductive layer (8 1 ) will form a uniform electric field and current distribution, and since the upper/lower conductive layers (81) / (82) are uniform resistive conductive layers, respectively, the upper conductive layer (81) A 1 〇 ssy capacitor is formed between the substrate (80) and the lower conductive layer (82). Therefore, the alternating current signal applied to the upper conductive layer (82) will form a loop of an alternating current signal through the lower conductive layer (82) and the ground end, and a current flows through the end point signal source and the lossy capacitor to the lower conductive layer. Layer (8 2 ) then flows out 'At this time, if the loaded power is (1) (2) (3) v = V〇sin( wt ) then the current measured at the endpoint can be expressed as la = IaO sin( Wt + 0 a ) lb = IbO sin( wt + 0 b ) The current at the endpoint differs from the phase of the applied voltage by 0 a, respectively. b When a grounded or loopable conductive object contacts the touchpad, The potential of the contact point P changes, and the condition of the electric field and current distribution uniformly distributed in the upper conductive layer (8 1 ) also changes, and the magnitude and phase of the current flowing through the end point also change. State Equation (see figure 4):

VxH = (σ + jw£ ) E = J(7s+ Jds (4) where J〇rS and Jds are the surface conduction current density and displacement current density of the upper conductive layer (8丄). ^ σ s / Jds == ο* / jw ε (5) , if the upper/lower conductive layers (81)/(82) are uniform conductive materials (8 〇) are uniform materials, σ, ε are unchanged, and their phase is 1251782 It is fixed. So assume its characteristic impedance (intrinsic impedence)

Zs = Rs + j Xs (6) Then the impedance between pa and pb can be expressed as Rpa = 1 ( Rs + jXs ) (7) Rpb = m( Rs + jXs ) (8) Therefore, the current change at the end point can be expressed as △ Ia = ( V - Vx ) / Rpa (9) △ Ib = ( V - Vx ) / Rpb (10) Then, △ Ia / Δ Ib = Rpb / Rpa (11) and (9), (10) respectively Rewritten as △ Ia = ia sin( wt + 0 ) (12) △ Ib = ib sin( wt + 0 ) (13) △ Ia / △ Ib = ia / ib (14) From (7) - (14) It can be seen that Δ Ia / Δ Ib = ia / ib = m / 1 (15) Assume that the distance between pa and p_b is i + m = 2L, and the center point L is set as the coordinate origin, and the coordinate position of the contact point P can be Expressed as (16)

Xp = ( ib - ia ) / (ia + ib ) L or ia, ib is known, that is, from equation (16), if Aia, Aib, point current can be expressed as + illusion (18) + 0) ( 19) The lower conductive layer (82) can be converted to the contact point coordinate position Xp. At this point, Ia = IaO sin(wt + 0 a) + ia sin(wt Ib = IbO sin(wt +0 b) + ib sin(wt and the conventional capacitive touchpad often ignores the effect of 1251782, as after: The accuracy of image coordinate judgment, the reason for which is further detailed 2 When the lower conductive layer (82) is not considered or the conductive layer is not set, IaO = ib〇 = 0, 曰la = ia sin( wt + 0 ) lb = ib sin( wt + 0 ) is again obtained by equations (20), (21) |Ia|-|ia| |Ib|-|ib| (20) (21) (22) i (23) Equations (22) and (23) are substituted into equation (16) to obtain the χρ coordinate position, (24) However, it must be noted that if the touchpad is not provided with conductive chips (8 2 ), the upper conductive layer The electric field distribution of (8 i ) will be very susceptible to changes in the radiation of the night crystal display (LCD) or the cathode ray tube screen (CRT), resulting in an unstable electric field distribution, which in turn makes the reading of the contact point unstable. (If the touch panel is provided with a lower conductive layer (8 2 ), a capacitor is formed between 1) 〆 (8 2 ) of the upper/lower conductive layer, so the current IaO at the front ends of the touch panel is not touched, IbO It must not be embarrassing, so at (1 8), (19) among them |Ial ^ |la〇| + |ia| 丨1bl 篆|IbO| + |ib| Similarly, Δ Ua| φ |ia| 1251782 △丨1b| 美|ib| If the assumed value of Δ |Ia| = |ia|, Λ π 丨AlIbl =卟| is substituted into equation (16), the contact point coordinate 1罝 is inaccurate, and the load at § P is changed. It is also known that the service of the 9th to the different coordinate values. As can be seen from the above, the conventional Rayleigh 4 & electric touchpad ignores the influence of the lower conductive layer on the correctness of the coordinate measurement, and thus the measurement coordinates are not Accurate results, so it is necessary to further review and seek a feasible solution. SUMMARY OF THE INVENTION Accordingly, the main object of the present invention is to provide a capacitive touch panel control method that can greatly improve the accuracy of measurement coordinates. The main technical means adopted for the foregoing purposes include the following steps: inputting a fixed voltage AC signal to the touch panel; obtaining a current signal at the end of the touch panel; sampling the measurement current signal; amplifying the sampling signal reading; comparing the sales number Whether the reading is greater than a threshold to determine whether the touchpad is pressed When it is judged that it is not pressed, the measurement signal reading is recorded; when it is judged that it is pressed, the coordinate position of the pressed contact is converted by the difference of the measurement signal before/after the pressure contact; Consider the influence of the conductive layer under the touchpad and eliminate its influence. 'Further increase the current signal reading based on the sensitivity analysis result to eliminate noise interference, and thus effectively improve the accuracy of the converted coordinates. 1251782 1j Before describing the measurement of the current signal, the measurement of the current signal is first applied to the measurement of the current signal. By appropriately increasing the level of the measurement signal, the current change value of the touch panel before and after being pressed is Most of the measurement current signals take the fixed phase in several cycles of converting the current signal into a voltage waveform, and then integrate to amplify the reading. The aforementioned method of sampling the current signal uses an integration method. The phase value method is used for sampling the current k number. After the amplified sampling signal reading is just described, the sampling signal is converted into a digital signal, and then the operation comparison is performed. A second object of the present invention is to provide a capacitive touch panel control device that can greatly improve the standard accuracy of the measuring head. The main technical means adopted to achieve the foregoing objectives are that the apparatus includes: a processing unit as an arithmetic/control hub, the output end of which is connected to a host on which the touch panel is mounted; and an AC signal generating unit controlled by the processing unit To generate an AC signal; a chemical supply/detection unit is provided by the aforementioned AC signal generating unit to provide an AC signal 'and is fed by the opposite end of the touch panel, and simultaneously detects a current signal at the same end point; The quasi-shift unit is controlled by the processing unit to level shift the current signal detected by the signal supply/detection unit to make the current signal before the touch panel is not pressed by the detection current signal Medium 1251782 removal; shift-sampling unit is controlled by the processing unit to sample the current signal processed by the level; and the above-mentioned sampling signal is controlled by the processing unit, and the number is amplified; * - An analog/digital conversion unit, which converts the aforementioned analog analog signal into a digital signal and sends it back to the processing unit it, After the calculation processing unit generates accurate coordinate position back to the host. The processing unit includes: a shifting unit for adjusting a quasi-shifting control unit, and connecting the level to the level of the shifting amount; the element is controlled to control the number of sampling and the sampling control unit is connected to the sampling list and The length of time; the large value; the product is the control unit, which is connected to the integrating amplifier to control the calculation unit 7G, which is respectively connected to the above-mentioned level shift control unit, sampling control unit, integral control unit and AC signal generating unit to control At the same time, it is connected with the analog/digital conversion unit and the host to capture the current signal after shifting and amplification, and then convert it into an accurate coordinate signal and send it back to the host. The output of the signal supply/detection unit is provided with a filter for removing noise in the output current signal and then sending it to the level shifting unit. [Embodiment] 1251782 The control method of the present invention is first shown in the first figure, and includes the following steps: inputting a fixed voltage AC signal to the touch panel (1〇1); obtaining the current of the touch panel end point Signal (102); Filter out noise of different frequencies to ensure the correct signal (1〇3); After the current is converted into voltage, the waveform is sampled at a fixed phase (1 Q 4 ) ·, the above sampled signal is amplified, and then amplified Sampling signal reading (丨05); Determine whether the touchpad is pressed according to the reading of the sampling h number (1 Q β ) 'If the sampling signal reading is less than the threshold value, then it is determined that there is no pressure touch, then the sampling signal is recorded. Reading (108); if the sampling signal reading is greater than the threshold value, the determination is pressed, and the point coordinate of the pressing contact is calculated and transmitted back to the host (107) according to the difference between the reading and the untouched reading; The control board is composed of a substrate, an upper/lower conductive layer and an upper/lower insulating layer. Due to the presence of the lower conductive layer, a current signal is present before the touchpad is not pressed. The foregoing method mainly eliminates the touchpad pair. Row of touch point coordinates In addition to the influence of the aforementioned current signal, the specific technical means will be further detailed as follows: In order to ensure the correctness of the measurement coordinates, the present invention proposes two methods for the current signal before and after the touch panel is pressed by the lower conductive layer. The change value ia, ib is separated from the current signals Ia, Ib actually measured by the touchpad after being pressed, that is, the current signal Ia〇, Ib〇 before the touchpad is not pressed, is removed. In step (107) of the foregoing method, only part of the work can be achieved with a part of the hardware in the specific implementation to reduce the complexity of the system by 10,125,782 degrees, which can be utilized before sampling the measurement signal. A quasi-shifting method increases the level of the 1 current signal (1 〇 3 A), so that the current signal change value ia, ib before and after the touch panel is pressed is the majority of the measured current signal. A system scale that helps simplify subsequent steps. After removing the IaO, the measured current signal of IbO is further subjected to a sampling step, which is to take out the amount of the fixed phase in a plurality of cycles in which the measured current signal is converted into a voltage waveform, and the specific technical means may be at least the following two types: 1 · Integration method for the integration of the left and right sides of (18), (19), from wt = hoarding to wt = π (25) (26) (27) (28) then (27) (28)

(29) (30) (31) (32) (33)

Ha dt = $ IaO sin( wt + 0 a) dt + $ ia sin( wt + 0) dt S Ib dt = $ IbO sin( wt + (/) b) dt + $ ib sin( wt + 0 ) dt M = S Ia dt, N = S Ib dt, Bay UM = IaO cos ψ a+ ia cos φ N = IbO cos ψ b+ ib cos φ where ia=0, ib=0 when the touchpad is not pressed , becomes M = IaO cos φ a Ν = IbO cos φ b From (27) to (30) Δ M = ia cos φ △ Ν = ib cos 0 thus △ Μ /△ Ν = ia/ib (33) Substituting (16) can obtain the contact point coordinate position 11 1251782 ΧΡ ^ (Δ Ν - Δ Μ) / (Δ Μ + Δ Ν ) L (34), that is, the invention can use the integral method to take the integral difference The scale of the value is calculated from the coordinates of the contact point. 2 · If the phase value is taken at a fixed time phase, Ia(F) = la〇sin(F + (/) a) + ia sin( F+ 0 Ib(F) - Ib〇sin( F + 0 b) + ib sin( ¥ + φ Δ Ia(F) = ia sin( F + 0 ) Δ Ib(F) = ib sin( ¥ + φ ) , then (18)(19), F=wT0, ) (35) ) (36) (37) (38)

(39) Thus Δ Ia(F)/A Ib(F) = ia /ib Substituting (3 9) into (16) the contact point coordinates are Xp = (Alb(F) -AIa(F)) / (Alb( F) + Ala(F)) (40) From the above, we can use the integral method or phase value method for

The measurement signal is sampled to convert its exact coordinate position, but to ensure the correctness of the coordinate calculation, the present invention will further analyze the stability of the aforementioned signal and make corresponding measures according to the analysis result. First, in terms of stability analysis, the contact point coordinates can be obtained from equations (34) and (4〇), and the sensitivity relationship between the coordinate values and △&”) and Δ Ib(F) is (41).

Sa= 5Xp/5 AIa = -2Aib/(AIa+ Alb)2

Sb=(5Χρ/δ AIb = 2Aia/(AIa+ Alb)2 (42) The analytical results obtained by equations (41) and (42) are: If 八1&, 八11) is small, then Sa, Sb becomes larger, That is to say, when there is a slight change in △ Ia, △ Ib, the coordinate Xp will have a large change, and it is easily affected by noise (n〇ise), causing the point coordinates to change significantly due to minute noise. Therefore, regardless of the integration method or the 12 1251782 phase value method, the reading value of ' and a 'ΔU must be increased to reduce the influence of noise. Therefore, the present invention further describes a method for making the system large. Change value: It is known from equations (35) and (36).

Ia(F) = IaO sin( F + 0 a x ,.. φ a ) + ia sin( F + 0 )

Ib(F) = IbO ^n(F+0b) + ibsin(F+^ can first IaO (43) (44) « It uses the aforementioned level shift (Level Shift) means Sin(F+0a), Ib 〇sin(F+0b) is removed

Ia(F) = ia sin( F + 0 )

Ib(F) = ib sin( F + 0 ) and then enlarge the fingerprint after the level shift is completed, and the resulting

Ia(F), Ib(F) is the value of ia, ib after zooming in. The above-mentioned magnification δ Bayes value can then be satisfied. And the way to put the female Lu Xu ", Jing number can be achieved by means of integrators using integrals. As another figure, there is a block diagram of the device that can perform the aforementioned method, which includes: , processing the single 7L ( 1 Q ) ' as the arithmetic / control center, and its output is connected to t · | - operation] η, in the present embodiment, is composed of a quasi-shift control unit (1 2 ), a sampling control unit (13) integral control unit (14) An AC signal generating unit (? η, 义么一平凡(Ζ ◦), which is controlled by the processing unit (! η ) in 丨丨^ 1 υ , 丄丄) to generate an AC signal; No., the detecting unit (30) is provided with an alternating current signal by the aforementioned alternating current signal (2G) and is input by the opposite end material 13 1251782 of the touch panel to simultaneously detect the current signal at the same end point; The quasi-shift unit (40) is processed by the level shifting of the batch I I - 1 0) the middle wave...) is controlled by its wheel-in end transmission-output: D and the aforementioned signal supply, the detection unit (30) The output of shlfr/ will be the second of the level signal of the detected current signal = the touchpad is pressed The current change value before and after the measurement signal, 4 knives, and m (41) is used to eliminate noise. 9 Sampling list 70 (50), subject to the aforementioned processing unit (1 〇 = control unit (13) Controlled, the input terminal is connected with the level shift: 疋 (4 Q ) output to sample the number of the position shift processing; the sampling unit (5 G ) is as described above The measurement current signal may be sampled by an integration method or a phase value method, which is controlled by the aforementioned processing unit (丄〇), and an integral control unit in an integrating amplifier (6〇) is performed on the sampling signal (1 4 Enlarged processing; analog/digital conversion unit (7 〇), which converts the amplified analog current signal into a digital signal and sends it back to the processing unit (11) in the processing unit (i 〇), from the operation list s ( 11) After the operation, an accurate coordinate position is generated and sent back to the host. The specific working mode of the foregoing device is as follows: After the system is started, the operation unit (i丄) transmits the level shift control unit (1 4 The control level shifting unit (4 〇) generates a predetermined shift bit The quasi-'俟 signal supply/detection unit ^ ( 3 Q ) f is the current signal before the 1251782 touchpad is not (four), and is sent back to the arithmetic unit after level shifting, sampling, integral amplification, analog/digital conversion. (ιι), and then the arithmetic unit (1 1) determines whether the preset shift level is appropriate, and then adjusts it by the level shift control unit (i 4). When the touchpad is touched The signal supply/detection unit (3 〇) will still detect its current signal, and the change value before and after the contact of the touch panel before and after the touch panel is separated by the above-mentioned level shifting unit (4 〇), and then by the sampling unit (50) sampling, the sampling unit (50) extracts the fixed phase amount _ in a plurality of cycles of measuring the current signal by using an integration method or a phase value method, and as the number of phases and phases of the obtained signal are obtained, It is controlled by the arithmetic unit (1 1 ) via the sampling control unit (13). - The aforementioned sampling signal _ step _ step is integrated by the integral (6 〇) into the lamp integral 'the multiple of its integral is determined by the arithmetic unit (worker) through the integral control unit (1 4 ); After the analog/digital conversion, it is sent back to the operation unit (11), and converted into an accurate coordinate signal by the operation Tsuiyuan (1 1 ) and sent back to the host. As described above, the present invention considers that the touch parameter uses a quasi-shifting method to be affected by the lower conductive layer and excludes the existing current signal, and further improves the score according to the sensitivity analysis result, and then: Current signal readings to eliminate noise interference, which effectively improves the accuracy of the conversion block h. Compared with the control mechanism of the existing capacitive touch panel, this technology has greatly improved the accuracy of the coordinate calculation, so it has significant efficiency enhancements and meets the patent requirements of the invention. 15 1251782 [Simple description of the diagram] (1) Schematic part The first figure is a flow chart of the present invention. Second Figure: A block diagram of the system of the present invention. The third picture is a schematic diagram of the structure of the touch panel. Figure 4: Vector diagram of the conduction current density and displacement current density of the conductive layer above the touch panel. (2) Component representative symbol (10) Processing unit (11) Operation unit (1 2 ) Level shift control unit (1 3 ) Sampling control unit (1 4 ) Integral control unit (2 0 ) AC signal generating unit (3 0) Signal supply/detection unit (40) Level shifting unit (4 1 ) Filter (50) Sampling unit (60) Integrating amplifier (7 0 ) Analog/digital conversion unit (80) Substrate (81) Conductive layer (8 2 ) under conductive layer ( 8 3 ) ( 8 4 ) insulating isolation layer 16

Claims (1)

Pick-up, patent application scope: 1 · A capacitive touch panel control method, comprising the following steps: inputting a fixed voltage value AC signal to the touch panel; obtaining a current signal at the end of the touch panel; and measuring the current signal Sampling; amplifying the sampling signal reading; 曰 comparing the measured signal reading is greater than a threshold to determine whether the touchpad is depressed; when it is judged that it is not pressed, the measurement signal reading is recorded; _ judged to have been touched At the time, the coordinate value of the measured contact signal is changed to the coordinate position of the pressed contact. 2 · A control method of a capacitive touch panel, comprising the following steps: inputting an AC signal with a fixed voltage value to the touch panel; obtaining a current signal at the end of the touch panel; and mentioning two: !: the level of the measurement signal, The current change value before and after the touchpad is pressed and touches most of the measured current signal; sampling the measurement current signal; amplifying the sampling signal reading; determining the touch panel Compare whether the measured signal reading is greater than a threshold and whether it is pressed; when it is judged that it is not pressed, the measurement signal reading is recorded. When it is judged that it has been pressed, the signal is measured before/after the pressure touch. The difference is changed to 17 i I --94 17 r:l| The coordinate position of the pressed contact is different. Control Ut:;Special: The range of the capacitive touch panel described in item 1 or 2 will capture the current signal at the end of the touch panel, and the noise of different frequencies will be decoded to ensure correctness. Signal. Considering the "manufacturing method of the capacitive touch panel described in item 1 or 2 of the profit range, the sampling method of the k is an integration method. (4) ^ For the method of clamping the capacitive touch panel according to the first or second aspect of the patent, the signal sampling method adopts a phase value method. (4) ^If I ask for the capacitive touch panel described in the scope of the patent range 1 or 2? The large reading current signal is amplified by integral or 遽 1 to remove the noise that is amplified by the same day. 7 · If the control method of the capacitive touch panel mentioned in the sixth paragraph of the patent scope is used, the sampled h after the magnified reading Zhao Wei μ & twisted t t number is first converted into a digital signal Danjin Comparison of operations. 8 A control device for a capacitive touch panel, comprising: connected to the second::: 'as the operation 'control center, the output end is connected to the main body of the main women's touch panel; Yuan, get Kwalu _ flow signal; $ system, and deal with early-control, to produce a supply/detection unit, the injury is traced by the poems, and the parental signal generation unit/parent 々IL k, and the current signal on the same point and the same end point of the touchpad; the simultaneous detection of the phase... the level shifting unit is controlled by the processing unit, and the signal is supplied. "The current signal detected by the detection unit is level shifted (level 18 丄) to remove the signal from the ... before the touchpad is not pressed; 々丨l "No. by the detection current, a sampling unit, is a quart Σσ One-time processing of the current signal is taken as follows: the early input and the second input: the device is the processing unit (4), and for the aforementioned sampling signal analog/digital conversion unit, you convert the operation stream signal into digital digits through the amplification processing unit. As an analogy of the dumb... After the electric y 戈 丨 l 达 达 达 达 达 l l l l l l l l l l l l l l l l l l l l l l l 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 The quasi-shifting control element is connected to the level shifting unit to control the level of movement of the level; 亍Λ ^ a sampling control unit, the connection and the length of time; 4 m control sampling quantity product is the control unit, to be Speed technology 兮 large value; system, connect 5 Hai integral amplifier 'to control its release system: the arithmetic unit, respectively connected to the above-mentioned level shift control unit, sampling before the system, the integral control unit and the first job 乜唬 Generate early 兀, to control its rr.ft ° u ratio / digital conversion unit and host connection, in order to take the =1 quasi-shift and amplified current signal, and then converted to the accurate spoon to know the L number is sent back to the host. The control device of the capacitive touch panel according to item 8 of the patent application scope is provided with a chopper at the output end of the signal supply/detection unit, and 19 is removed from the output current signal. Special ', 11 and then send Level shifting unit. 5. Month patent range qth device, which takes Mm < brother 9 out of the capacitive touch panel control cycle to take a fixed phase of two take = two measurements: several of the stream signal The unit is controlled by the material sample control unit. (4) The quantity and position are controlled by Yun 12: The control of the capacitive touch panel according to the scope of claim 9 is taken by the phase value method to measure the current signal. The number of fixed phases is taken out in several cycles, and the number and position of the fetch cycles are determined by the arithmetic unit through the sampling control unit. 20