WO2011035486A1 - 一种可排除显示影响触控的触控显示器 - Google Patents

一种可排除显示影响触控的触控显示器 Download PDF

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Publication number
WO2011035486A1
WO2011035486A1 PCT/CN2009/074257 CN2009074257W WO2011035486A1 WO 2011035486 A1 WO2011035486 A1 WO 2011035486A1 CN 2009074257 W CN2009074257 W CN 2009074257W WO 2011035486 A1 WO2011035486 A1 WO 2011035486A1
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WIPO (PCT)
Prior art keywords
touch
display
signal
liquid crystal
electrode
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PCT/CN2009/074257
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English (en)
French (fr)
Inventor
陈其良
刘海平
李德海
Original Assignee
智点科技有限公司
智点科技(深圳)有限公司
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Application filed by 智点科技有限公司, 智点科技(深圳)有限公司 filed Critical 智点科技有限公司
Priority to EP09849674A priority Critical patent/EP2463757A1/en
Priority to PCT/CN2009/074257 priority patent/WO2011035486A1/zh
Priority to JP2012530085A priority patent/JP5481740B2/ja
Priority to CN2009801013701A priority patent/CN102132231A/zh
Publication of WO2011035486A1 publication Critical patent/WO2011035486A1/zh
Priority to US13/416,549 priority patent/US20120162133A1/en

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Classifications

    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06FELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/0412Digitisers structurally integrated in a display
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06FELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/0416Control or interface arrangements specially adapted for digitisers
    • G06F3/0418Control or interface arrangements specially adapted for digitisers for error correction or compensation, e.g. based on parallax, calibration or alignment
    • G06F3/04184Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06FELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/044Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by capacitive means
    • G06F3/0443Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by capacitive means using a single layer of sensing electrodes

Definitions

  • Touch display capable of eliminating display affecting touch
  • the present invention relates to a touch screen and a flat panel display, and more particularly to a touch display.
  • Touch screen development has been widely used in many fields such as personal computers, smart phones, public information, smart home appliances, industrial control, and the like.
  • touch field there are mainly resistive touch screens, photoelectric touch screens, ultrasonic touch screens, and flat capacitive touch screens.
  • resistive touch screens In recent years, projected capacitive touch screens have developed rapidly.
  • touch screens all have their own technical shortcomings, which makes them widely used in some special occasions, but it is difficult to promote the application on ordinary displays.
  • the display screen and the touch screen are twin products.
  • the display screen and the touch screen are usually independently responsible for display and touch tasks.
  • the discrete flat panel display with touch function is composed of a display screen, a display driver, a touch screen, a touch signal detector, a backlight, and the like.
  • the touch screen has a resistive type using different sensing principles. Capacitive, electromagnetic, ultrasonic and photoelectric, etc., display with passive liquid crystal display (TN/STN-LCD), active liquid crystal display (TFT-LCD), organic light-emitting diode display (OLED, AM- OLED), plasma display panel (PDP), carbon nanotube display, e-paper, etc.
  • a flat panel display with a touch screen stacks a separate touch screen and a display screen, detects the planar position of the touch point through the touch screen, and causes the cursor on the display screen to follow the touch point.
  • the cascading of the touch screen and the display screen makes the touch panel display thicker and heavier and the cost increases; when the touch screen is placed in front of the display screen, the reflection generated by the touch screen sensing electrode makes the display uneven and strong. The contrast is reduced in the external light environment, which affects the display effect. Integrating the touchpad and the display to make the flat panel display with touch function lighter and thinner is the direction of people's efforts.
  • the basic working principle of the touch panel display disclosed in the above Chinese patent is that two sets of intersecting electrodes on the display screen are used as the touch sensing electrodes, and the electrode lines of the electrode group are connected to the touch excitation source, and the touch excitation is performed.
  • the source applies an alternating current or direct current touch excitation signal to the electrode line.
  • the touch circuit detects the change of the touch signal of each electrode line to find the position of the finger or other touch object on the display screen. .
  • the present invention is an improvement in its effect in eliminating the influence of display content changes on touch signal detection.
  • the present invention provides a touch display capable of eliminating display effects, including an active liquid crystal display, a display driving circuit, a touch circuit, and a display for making the display electrode both for display driving and for touch detection.
  • a touch signal strobe output circuit or a display/touch signal loading circuit the touch circuit has a touch excitation source and a touch signal detection circuit; and the display/touch signal strobe output circuit causes the display electrode or
  • the display driving circuit communicates with the transmission display driving signal, or communicates with the touch detection circuit to transmit the touch signal, and the display driving and the touch detection time division multiplex the display screen electrode;
  • the display/touch signal loading circuit enables the display electrode to simultaneously transmit and display
  • the liquid crystal pre-drive signals applied on part or all of the row and column electrode lines and the common electrode of the display screen are applied to different row and column electrode lines at the same time or at different times; and the liquid crystal pre-drive signal is applied to the row and column electrode lines. During the time period, there is also a time at which the liquid crystal pre-drive signal is applied to the common electrode.
  • the liquid crystal pre-drive signal applied on part or all of the row and column electrode lines of the display screen and the common electrode is applied after applying a liquid crystal pre-drive signal to part or all of the row and column electrode lines and the common electrode of the display screen.
  • Liquid crystal The row and column electrode lines of the pre-drive signal apply a touch signal, and detect a change of the touch signal on the electrode line.
  • the liquid crystal pre-drive signal applied on part or all of the row and column electrode lines and the common electrode of the display screen is performed while applying a touch signal to the row and column electrode lines, or after applying a touch signal to the row and column electrode lines, A liquid crystal pre-drive signal is applied to some or all of the row and column electrode lines and the common electrode of the display screen; after the liquid crystal pre-drive signal is applied, the change of the touch signal on the electrode line to which the liquid crystal pre-drive signal is applied is detected.
  • the active device array on the display screen is a TFT array, and the row and column electrode lines are respectively connected to the gate and the source of the TFT, or respectively connected to the gate and the drain of the TFT, and the column electrode line connecting the source or the drain of the TFT There is a period of time during which the liquid crystal pre-drive signal is applied simultaneously.
  • the liquid crystal pre-drive signal is applied to some or all of the row and column electrode lines of the display screen and to the common electrode, and is a period in which all or part of the active devices connected to the display pixels are in an off state on the display screen.
  • the liquid crystal pre-drive signal is applied during an on-state period of the active device connected to the display pixels on the display screen.
  • the liquid crystal pre-drive signal and the touch signal are simultaneously applied during an on-state period of the active device connected to the display pixel on the display screen.
  • the active device array on the display screen is a TFT array, and a liquid crystal pre-drive signal is applied to the column electrode lines and the common electrodes connecting the TFT source or drain during the on-state of the TFTs connected to the display pixels.
  • the liquid crystal pre-drive signal applied to the row or column electrode group or the common electrode is one of an alternating current signal, a direct current signal, and an alternating current and direct current mixed signal.
  • the liquid crystal pre-drive signal and the touch signal applied to the same electrode of the display screen are AC signals having the same frequency or waveform.
  • the frequency of the liquid crystal pre-drive signal is 10 kHz or more.
  • the method disclosed in the present invention provides a uniformity for the touch detection by setting the saturation pre-drive process so that the alignment of the liquid crystal molecules between the row electrode and the COM electrode and between the column electrode and the COM electrode of the liquid crystal display screen is uniform.
  • the measurement environment avoids the touch detection being affected by the displayed content.
  • FIG. 1 is a typical structural view of a TFT-LCD display
  • FIG. 2 is a schematic structural view of a display sub-pixel of a TFT-LCD
  • Figure 3 is a timing chart of a conventional display driving of a TFT-LCD liquid crystal display
  • FIG. 4 is a structural view of a touch display of a TFT-LCD display
  • Figure 5 is a timing diagram of a time division multiplexed display electrode
  • 6 is a waveform diagram of a touch excitation signal according to a first embodiment
  • 7 is a waveform diagram of a touch excitation signal according to a second embodiment
  • FIG. 8 is a waveform diagram of a touch excitation signal according to a third embodiment
  • FIG. 9 is a waveform diagram of a touch excitation signal according to a fourth embodiment.
  • FIG. 10 is a waveform diagram of a touch excitation signal according to a fifth embodiment
  • FIG. 11 is a waveform diagram of a touch excitation signal according to Embodiment 6;
  • FIG. 12 is a timing diagram of a time division multiplexed display screen electrode according to Embodiment 7 and Mode 8;
  • FIG. 13 is a waveform diagram of a touch excitation signal according to Embodiment 7 and Mode 8;
  • Figure 14 is a sequence diagram showing the arrangement of molecules of a positive liquid crystal material in an external field
  • Figure 15 is a sequence diagram of molecular arrangement of negative liquid crystal materials in an external field
  • Figure 16 is a timing chart of a time division multiplexed display screen electrode according to a ninth embodiment
  • Figure 17 is a timing chart of the time division multiplexing display screen electrode of the tenth embodiment
  • Figure 18 is an equivalent circuit diagram when a finger touches the display screen
  • Figure 19 is a graph showing the leakage current ⁇ of the touch signal generated by the touch as a function of frequency
  • Figure 20 is an equivalent circuit diagram when the COM electrode is disposed on the upper substrate glass, when the finger touches the display screen;
  • Figure 21 is the touch of the touch excitation source and the touch signal sampling point when the touch excitation signal is a square wave
  • FIG. 22a, 22b, and 22c are schematic diagrams of a complete synchronization process of the touch detection when the touch excitation signal is a square wave;
  • FIG. 23 is a touch excitation source and a touch when the touch excitation signal is a sine wave;
  • FIG. 24a, 24b, and 24c are schematic diagrams of a complete synchronizing process of the touch detection when the touch excitation signal is a sine wave;
  • FIG. 25 is a touch signal detection method of the instantaneous value measurement method. Circuit structure diagram;
  • 26 is a structural diagram of a touch signal detecting circuit of an instantaneous value measuring method
  • Figure 27 is a structural diagram of a touch signal detecting circuit of an instantaneous value measuring method
  • 29 is a structural diagram of a touch signal detecting circuit of an effective value measuring method
  • Figure 30 is a structural diagram of a touch signal detecting circuit of an effective value measuring method
  • 31 is a time characteristic of a touch excitation signal being a square wave and a touch signal of a touch signal sampling point;
  • 32 is a structural diagram of a touch signal detecting circuit of a time characteristic measuring method
  • Figure 33 is a structural diagram of a touch signal detecting circuit of a time characteristic measuring method
  • Figure 34 is a structural diagram of a touch signal detecting circuit of a phase shift measuring method
  • Figure 35 is a structural diagram of a touch signal detecting circuit of a phase shift measuring method
  • 36 is a schematic diagram of a detection sequence of a touch detection method for single-channel sequential scanning
  • 37 is a schematic diagram of a detection sequence of a touch detection method for single-channel interval scanning
  • 38 is a schematic diagram of a detection sequence of a single channel coarse sweep and fine sweep touch detection method
  • 39 is a schematic diagram of a detection sequence of a touch detection method for multi-channel sequential scanning
  • 40 is a schematic diagram of a detection sequence of a touch detection method for multi-channel interval scanning
  • 41 is a schematic diagram of a detection sequence of a multi-channel coarse scan and fine sweep touch detection method.
  • the invention is applicable to a liquid crystal display (LCD) including a row electrode and a column electrode, an organic light emitting diode display (OLED, AM OLED), a plasma display (PDP), a carbon nanotube display, an electronic paper ( E-paper) and other flat panel displays.
  • LCD liquid crystal display
  • OLED organic light emitting diode display
  • AM OLED organic light emitting diode display
  • PDP plasma display
  • COD organic light emitting diode display
  • E-paper electronic paper
  • LCD Thin Film Transistor LCD
  • TFT-LCD Thin Film Transistor LCD
  • the thin film FET liquid crystal display is a typical representative of an active matrix liquid crystal display (AM LCD), which uses a thin film field effect transistor on the substrate (TFTM ⁇ is a switching device.
  • a typical structure of a TFT-LCD display is shown in FIG. : 110 is a TFT liquid crystal screen; 120 is a liquid crystal screen horizontal scanning line electrode, 121, 122, ..., 12m-K 12m is a scanning electrode line (row electrode line); 130 is a liquid crystal screen vertical direction data column electrode, 131 , ..., 13n are data electrode lines (column electrode lines); 140 is a common electrode (COM electrode), the potential of the common electrode connection is a reference potential as a liquid crystal display pixel; 150 is a thin film transistor TFT on a liquid crystal panel, The gate is connected to the horizontal scanning line, the source is connected to the vertical data line, and the drain is connected to the display pixel electrode; 160 is the liquid crystal molecular box corresponding to the display pixel, electrically Equivalent to a capacitor, this
  • a display pixel is generally composed of three sub-pixels that display three primary colors of red, green, and blue.
  • a schematic diagram of a display sub-pixel is shown in FIG. 2: Gi represents a horizontally-line scan electrode line, also referred to as a row drive electrode line or a gate drive electrode line, and the potential on Gi is Vg; Sj represents a vertical direction column data electrode line.
  • the potential on Sj is Vs;
  • Dij represents the terminal of the TFT connected display pixel, called the drain, and the potential on Dij is Vd, also called the pixel potential;
  • the display pixels are each provided with a semiconductor switching device - a field effect transistor (TFT) on the thin film substrate, which can be directly controlled by pulse to perform display scanning, and thus each pixel is relatively independent.
  • the voltage between the gate and the source of the TFT is Vgs, between the gate and the drain of the TFT.
  • the voltage is Vgd.
  • Thin film field effect transistors (TFTs) are available in both MOS and PMOS types.
  • a-Si amorphous silicon
  • SiNx silicon nitride
  • NMOS type thin film field effect transistors PMOS type thin film field effect transistors can follow the principle of communication, and the descriptions are not listed separately.
  • the timing of the TFT-LCD liquid crystal display is not shown in Figure 3.
  • the display driver circuit performs sequential scanning display on the row electrodes, and the column electrodes and COM electrodes cooperate with the output.
  • Display signal the display is in the display state; there is a frame blanking time period (Vertical Blanking Time) between every two display scanning time periods, in which the display does not perform display driving, the display driving circuit is on the line
  • the electrode scanning stops, and the non-selection signal of the TFT is output to all the row electrodes, and the column electrode and the COM electrode maintain the original output state or a certain preset output signal, and the TFT is in an off state.
  • the time division multiplexing display electrode electrode technology in the present invention utilizes the frame blanking period as a time period for multiplexing the display screen electrode as the detecting electrode.
  • the touch control circuit cooperates with the display driving circuit and the touch circuit to connect the display electrode or the display driving circuit to transmit the display driving signal or communicate with the touch circuit to transmit the touch signal, and the display driving and the touch detecting time Multiplex display electrodes.
  • the display electrode is connected to the display driving circuit to transmit the display driving signal, and the display screen is in the display state.
  • the touch detection period the display electrode is connected to the touch circuit to transmit the touch signal, and respectively detects the change of the touch signal flowing through each of the row electrode lines and the column electrode lines, so that the touch signal changes to a certain setting.
  • the conditional row electrode line and column electrode line are the touched electrode lines. From the detected intersection of the touched electrode line and the touched electrode line, the position of the contact is determined.
  • Embodiments 16 to 19 of the embodiments of the present invention disclose related touch signal detecting circuit structures.
  • the specific implementation manners 1 to 6 listed in the embodiments of the present invention are examples of selecting a reasonable touch excitation signal scheme to avoid the influence of the touch excitation signal on the display effect, and the specific implementation manner is as follows:
  • the specific embodiments 11 to 13 disclose the selection requirements of the frequency of the touch excitation signal
  • the specific embodiment 14 and 15 disclose the touch detection.
  • the control signal is detected and synchronized with the applied touch excitation signal.
  • the specific embodiment 20 to 23 reveals various single-channel and multi-channel touch detection scanning modes and sequences.
  • the electrical connection relationship of the touch display 400 with the TFT-LCD as the display screen is as shown in FIG.
  • the TFT-LCD display 410 is included; the scanning line electrode 420 of the TFT-LCD display screen has a row electrode line 421, ..., 42m; the data column electrode 430 of the TFT-LCD display vertical direction has a column electrode line 431, ..., 43n; TFT-LCD display
  • the liquid crystal cell 460 corresponding to the display pixel is electrically equivalent to a capacitor, and the capacitance is generally defined as CLC; (Capacitance Storage, Cs) 470, display information for storing pixels; display drive circuit 480
  • the display scan driving circuit 483 and the touch control circuit 484 are connected to the row electrode 420 through the row signal strobe output circuit 485; the display data driving circuit 486 and the touch control circuit 487 are connected to the column electrode 430 through the column signal strobe output circuit 488; The driving circuit 480 and the touch excitation source 481 are connected to the COM electrode 440 through the COM signal strobe output circuit 482.
  • the timing controller 489 receives the RGB data from the image signal processing chip, the clock signal Clock, the horizontal synchronization Hsync, and the vertical synchronization signal Vsync, and controls the row display driving circuit 483 that connects the gates, the column display driving circuit 486 that connects the sources, and the connection.
  • the COM display driving circuit 480 of the common electrode cooperates; the row touch circuit 484 for connecting the source, the column touch circuit 487 for connecting the gate, and the COM touch excitation source 481 for connecting the common electrode work together;
  • the row strobe circuit 485, the column strobe circuit 488 and the COM signal strobe output circuit 482 in the display enable the display electrode or the display driving circuit to transmit the display driving signal or communicate with the touch circuit to transmit the touch signal, and the display driver
  • the display electrodes are multiplexed with the touch detection time division.
  • the row strobe circuit 485, the column strobe circuit 488, and the COM signal strobe output circuit 482 in the touch display 400 cause the display row electrode 420, the column electrode 430, and the COM electrode 440 to respectively communicate with the row display driving circuit. 483.
  • the column display driving circuit 486 and the COM display driving circuit 480 transmit a display driving signal, and the display screen 410 is in a display state.
  • the row strobe circuit 485, the column strobe circuit 488, and the COM signal strobe output circuit 482 in the touch display 400 respectively cause the display row electrode 420, the column electrode 430, and the COM electrode 440 to communicate with each other.
  • the control circuit 484, the column touch circuit 487 and the COM touch excitation source 481 transmit the touch signals, and respectively detect the changes of the touch signals flowing through the respective row electrode lines and the respective column electrode lines, and the display row and column electrodes are switched as The touch sensing electrode is used; the row touch circuit 484 and the column touch circuit 487 detect that the row electrode line and the column electrode line that have passed the touch signal change to reach a certain set condition are the touched electrode lines. From the detected intersection of the touched electrode line and the touched electrode line, the position of the touch point on the display screen 410 is determined.
  • Figure 4 shows the structure of a typical touch display. The following description of the specific embodiments is based on this On the basis of structure.
  • the timing of the display electrode time division multiplexing scheme is as shown in FIG. 5.
  • the frame blanking period between each display frame is used as a touch detection period.
  • the display electrode is switched to be used as a touch sensing electrode, a touch excitation signal is applied on the display electrode, and the display screen is detected. The change in the touch signal on the electrode.
  • the touch excitation source is a square wave signal source having a DC bottom value or no DC bottom value.
  • the three electrodes of Gi, Sj, and COM of the TFT as shown in FIG. 2 are respectively applied with the touch excitation signal as shown in FIG. 6, and the three touch excitation signals applied have a DC bottom value. Or a square wave without a DC bottom value with the same frequency and phase.
  • the requirement that the TFT is in the off state of the off-state ensures that both Vgs and Vgd are lower than the cut-off voltage for turning off the TFT, thereby ensuring that the TFT can effectively cut off in the touch detection state and maintain the display pixels.
  • the voltage is such that the display effect is not affected by the touch detection.
  • the touch excitation source is selected as a square wave signal source having a DC bottom value or no DC bottom value, and the frequency and phase of the square wave signal sources are the same, and the amplitude of the jump is also uniform, so that the Gi, Sj, and COM of the TFT are three.
  • the difference between the excitation signals applied by the electrodes is a constant DC level. In fact, when the touch detection is performed, a simple detection circuit can be used to obtain a good detection effect, and the generation of the signal source is very convenient and has high practical value.
  • the difference between this embodiment and the first embodiment and the second embodiment is that the three touch excitation signals are square waves with or without a DC bottom value, and the frequencies are the same but the phases are inconsistent, as shown in FIG. 8 . Shown.
  • the difference between this embodiment and the first embodiment to the third embodiment is that, in the touch detection, the three electrodes of the Gi, Sj, and COM electrodes of the TFT shown in FIG. 2 are respectively applied with a touch excitation signal as shown in FIG.
  • the three touch excitation signals are sinusoids with a DC bottom value or no DC bottom value (note that Embodiments 1 to 3 are square waves instead of sine waves) with the same frequency and phase.
  • the Gi of the TFT is The three electrodes of Sj and COM respectively apply the touch excitation signal as shown in FIG. 10, and the three touch excitation signals applied are sinusoidal waves having a DC bottom value or no DC bottom value, and the frequency and the phase are opposite each other, but The amplitude of the waveform exchange section is different.
  • the difference between the first embodiment and the fifth embodiment is that, in the touch detection, the touch excitation signals are applied to the three electrodes of the Gi, Sj, and COM electrodes of the TFT shown in FIG.
  • the combination of the excitation signals does not keep the average value of the pixel electrode potential Vd and the COM electrode potential Vcom constant, but the average value of the potential difference Vd-Vcom of the two can be kept constant, and the display effect can be prevented from being touched. The impact of the detection.
  • the display adopts a TFT-LCD, and the TFT-LCD uses a positive liquid crystal material.
  • the anisotropy of the dielectric constant of the liquid crystal material causes the distributed capacitance in the liquid crystal cell to vary with the arrangement of the liquid crystal molecules.
  • the arrangement of liquid crystal molecules in the TFT-LCD depends on the effective value accumulated by the driving voltage at the same place.
  • the effective values of the driving voltages accumulated at different positions at different times are different, the liquid crystal molecules are arranged differently, and the distributed capacitance is also different.
  • the measurement environment is different. When a driving voltage is applied to the TFT-LCD, the alignment state of the liquid crystal molecules uniformly approaches the direction parallel to the electric field due to the action of the driving electric field.
  • FIG. 13 A further timing of the display electrode time division multiplexing scheme is shown in FIG.
  • the frame blanking period between each display frame is used as the touch detection period.
  • a saturated preset drive (pre-driving;) signals on the three electrodes Gi, Sj and COM are applied to all the row electrode lines Gi and the column electrode lines Sj of the display screen simultaneously.
  • the waveform is shown in Figure 13.
  • the touch excitation signal is a sine wave with a DC bottom value or no DC bottom value.
  • the potential difference Vgs between Gi-Sj is between -10.5V and -17V, which is lower than the cut-off voltage for turning off the TFT to avoid affecting the display.
  • the potential difference Vgc between Gi-COM is between -10.5V and -12V.
  • the potential difference Vsc between Sj-COM is 5V, which exceeds the saturation driving voltage of the liquid crystal molecules.
  • the liquid crystal molecules between the liquid crystal molecules, the column electrodes and the COM electrodes between the row electrodes and the COM electrodes in the liquid crystal display are aligned in a uniform direction and rapidly turn in a direction parallel to the electric field.
  • an electric field E is applied to the molecules of the positive liquid crystal material, the alignment of the liquid crystal molecules is parallel to the alignment state of the electric field direction.
  • a touch excitation signal is applied to the display row electrode line Gi and the column electrode line Sj, respectively, and the change of the touch signal flowing through each row electrode line and each column electrode line is respectively detected; the previous saturated pre-drive voltage makes The alignment of the liquid crystal molecules is uniform, and the variation of the distributed capacitance caused by the dielectric anisotropy of the liquid crystal material is excluded, and when the change of the touch signals on each row electrode line and each column electrode line is detected, the measurement at different times and at different positions is performed.
  • the environment tends to be consistent, which is conducive to the stability and consistency of the touch detection results.
  • the arrangement of the liquid crystal molecules in FIG. 14 is not affected by the positive and negative directions of the electric field, so the instantaneous voltage on the electrodes in the pre-drive section can be positive or negative, as long as the pair remains The saturation drive of the liquid crystal is sufficient. Therefore, the waveform or frequency of the pre-drive signal and the touch excitation signal applied to the same electrode of the display screen The rate and amplitude can be the same, and even the pre-drive signal and the touch excitation signal use the same signal.
  • the TFT-LCD in this example uses a negative liquid crystal material as shown in FIG.
  • the touch display 400 shown in FIG. 4 adopts a TFT-LCD. Since the response speed of the liquid crystal display is relatively low, after displaying a high-speed screen, image sticking and smearing are likely to occur. To solve this problem, the current one is One solution is to increase the frame rate of the display, insert a "black frame” after each frame, and let the "black frame” block the afterimage of the displayed content.
  • the so-called black frame is in this frame, in the state where the TFT is on, a saturation driving voltage is applied to the display pixel electrode through the column electrode Sj, so that the alignment of the liquid crystal molecules in the display pixel is consistent or perpendicular to the applied electric field. The direction.
  • the alignment of the liquid crystal molecules in the display pixel is uniform, the arrangement of the liquid crystal molecules between the column electrode and the COM electrode in the liquid crystal display panel will also be uniform. Since the row electrode is the scan electrode, the effective value of the voltage on each row of electrodes is the same. When the alignment of the liquid crystal molecules between the column electrode and the COM electrode is uniform, the distributed capacitance on each row of electrodes is substantially uniform.
  • the timing of the display electrode time division multiplexing scheme is shown in Fig. 16.
  • the touch excitation signals are applied to the display row electrode line Gi and the column electrode line Sj, respectively, and the changes of the touch signals flowing through the respective row electrode lines and the respective column electrode lines are respectively detected.
  • the use of black frames allows the liquid crystal molecules to be aligned, eliminating the variation of the distributed capacitance caused by the dielectric anisotropy of the liquid crystal material, and detecting the change of the touch signals on each row electrode line and each column electrode line, at different times.
  • the measurement environment at different locations tends to be consistent, which is beneficial to the stability and consistency of the touch detection results.
  • the touch display 400 shown in FIG. 4 adopts a TFT-LCD, and the same as the embodiment IX, in which a "black frame” is inserted after each display frame, so that the "black frame” blocks the display content before. Afterimage.
  • FIG. 9 Another timing of the display electrode time division multiplexing scheme is as shown in FIG. Applying a touch excitation signal to the display row electrode line Gi and the column electrode line Sj after the normal display frame and after the black frame, respectively, and detecting the touch signals flowing through the respective row electrode lines and the respective column electrode lines respectively Variety.
  • the frame blanking time between display frames is fully utilized, and the display electrode is switched to the touch sensing electrode in each frame blanking time; and the liquid crystal molecules are aligned in the black frame, and the liquid crystal material dielectric is excluded.
  • the variation of the distributed capacitance caused by the coefficient anisotropy comprehensive judgment to eliminate the influence of the inconsistent alignment of liquid crystal molecules on the detection environment.
  • the display adopts a TFT-LCD, and the glass substrate has a thickness of 0.3 mm.
  • the finger forms a coupling capacitor between the substrate glass piece and the display electrode, and the equivalent circuit is as shown in FIG.
  • the 1810 is a touch excitation source for providing a touch excitation signal to the display electrode
  • the 1820 is a sampling resistor of the touch signal detection circuit in the touch circuit
  • the 1821 is a set of display electrodes used as the touch sensing electrode.
  • Equivalent resistance, 1830 is the distributed capacitance of a set of display electrodes used as touch sensing electrodes with respect to other electrodes in the display.
  • 1831 is the coupling capacitance between the finger and a set of display electrodes used as touch sensing electrodes
  • 1832 It is a set of capacitance between the display electrode and the COM electrode used as a touch sensing electrode.
  • the relationship between the leakage current ⁇ caused by 1831 and the frequency of the touch excitation source is as shown in FIG.
  • the frequency of the touch excitation signal has a major influence on the capacitive reactance of the coupling capacitor 1831, and the capacitive reactance is different, and the magnitude of the touch signal that the current leaks from the finger is different.
  • the frequency is too low, and the coupling capacitance of the coupling capacitor 1831 is too small.
  • the touch display 400 is insensitive to the touch of the touch object, and is easy to generate a touch leak judgment.
  • the frequency selection of the touch excitation signal has a great influence on the reliability of the touch detection, especially when the protective cover is added in front of the display.
  • the display adopts a TFT-LCD, and the thickness of the glass substrate is 0.3 mm.
  • the COM electrode of the liquid crystal panel is disposed on the upper substrate glass facing the operator, the COM electrode forms a certain shielding effect between the row electrode and the column electrode and the operator.
  • Finger and display screen A coupling capacitor is formed between the COM electrodes.
  • the equivalent circuit is shown in Figure 20.
  • 2010 is a touch excitation source that provides a touch excitation signal to the display electrode
  • 2020 is a sampling resistor of the touch signal detection circuit in the touch circuit
  • 2021 is an equivalent resistance of a display electrode used as a touch sensing electrode.
  • 2030 is a distributed capacitance of a display electrode used as a touch sensing electrode with respect to other electrodes in the display
  • 2031 is a coupling capacitance between a COM electrode and a display electrode used as a touch sensing electrode
  • 2032 is a finger
  • the coupling capacitance between the excitation electrode and the COM electrode is the coupling capacitance between the excitation electrode and the COM electrode.
  • the overlap width between the finger and a set of display electrodes used as the touch sensing electrodes is 5 mm or less, the substrate glass thickness is 0.3 mm, and the coupling capacitance 2032 is about 10 pF ; for the usual TFT-LCD sampling resistor 2020 and the like The sum of the effective resistors 2021 is about 30 ⁇ .
  • the display uses a TFT-LCD.
  • the anisotropy of the dielectric constant of the liquid crystal material causes the distributed capacitance in the liquid crystal cell to vary with the arrangement of the liquid crystal molecules.
  • the arrangement of liquid crystal molecules in the TFT-LCD depends on the effective value accumulated by the driving voltage at the same place.
  • the effective values of the driving voltages accumulated at different positions at different times are different, the liquid crystal molecules are arranged differently, and the distributed capacitance is also different.
  • the measurement environment is different.
  • the anisotropy of the dielectric constant of a liquid crystal material has a dispersion effect with frequency, and the anisotropy of the dielectric coefficient is generally not reflected by the action of an electric signal of 500 kHz or more.
  • a touch excitation signal having a frequency of 1 MHz or more is applied to the display row electrode line Gi and the column electrode line Sj, and changes in the touch signals flowing through the respective row electrode lines and the respective column electrode lines are detected, respectively.
  • the arrangement of liquid crystal molecules is not uniform at different positions of the TFT-LCD, due to the anisotropic dispersion effect of the dielectric constant of the liquid crystal material, the dielectric constant of the liquid crystal material is excluded for the touch excitation signal of 1 MHz or more.
  • the display uses a TFT-LCD.
  • touch detection it is usually measured by using a voltage signal as a detection target.
  • the equivalent circuit of the measurement is shown in Figure 18.
  • the 1810 is a touch excitation source for providing a touch excitation signal to the display electrode
  • the 1820 is a sampling resistor of the touch signal detection circuit in the touch circuit
  • the 1821 is an equivalent resistance of the display electrode used as the touch sensing electrode.
  • 1830 is a distributed capacitance of a display electrode used as a touch sensing electrode with respect to other electrodes in the display
  • 1831 is a coupling capacitance between a finger and a display electrode used as a touch sensing electrode
  • 1832 is a group
  • the capacitance between the display electrode and the COM electrode used as the touch sensing electrode 1841 is a touch signal sampling point for measuring the change of the touch signal voltage
  • 1840 is a detection reference point for measuring the voltage change of the touch signal, here is a touch selection
  • the output end of the control excitation source 1810 is used as a reference point.
  • the touch excitation source 1810 is a square wave signal. Since the 1830 and 1831 are capacitive loads, the square wave signal excited by the touch appears a charge and discharge waveform on the two capacitors. The output waveform of the touch excitation source 1810 and the touch signal waveform of the touch signal sampling point 1841 are as shown in FIG. 21.
  • the instantaneous value measurement method is used to measure the potential of the touch signal sampling point 1841 at a specific phase point, and the specific phase point detected in different frame blanking time periods is compared.
  • the change in potential is used to obtain touch information;
  • the specific phase point is a specific phase point relative to the waveform of the output of the touch excitation source 1810.
  • the circuit shown in Figure 18 uses the excitation source signal as the circuit source.
  • the branch where the sampling resistor is located is the RC loop in which the 1830 and 1831 capacitors are connected in parallel and then connected to the 1820 and 1821 resistors.
  • the circuit shown in Figure 18 applies a touch excitation signal, and the circuit generates a charge and discharge process for the capacitor.
  • the T1 and T2 segments are suitable for the phase interval.
  • the phase interval of T1 is the period from when the capacitor starts charging to the completion of charging
  • the phase interval of T2 is the capacitor begins to discharge until the discharge is completed. period.
  • the synchronization relationship here consists of three peer relationships: display frame synchronization, touch excitation pulse number synchronization, and touch excitation waveform phase synchronization.
  • Display frame synchronization Each time the touch excitation signal is applied, it is a fixed time in the frame blanking period between two display frames; the number of excitation pulses is synchronized: from the start of applying the touch excitation signal to On the display electrode used by the touch sensing electrode, the number of touch excitation signal pulses is calculated, and the time at which the sampled data is acquired is at the same number of touch excitation signal pulses; the excitation waveform phase synchronization: each time sampling is taken The time of the data is at a specific phase point of the waveform of the output of the touch excitation source, and the position of the specific phase point is selected in the two phase intervals of T1 or T2. A complete synchronization process is shown in Figure 22a, Figure 22b, and Figure 22c.
  • Figure 22a is a timing diagram of the time division multiplexing of the display screen.
  • the row electrode, the column electrode, and the COM electrode of the display screen are in the display scanning period, and output corresponding display signals, sequentially performing display scanning, and the row electrodes on the display screen,
  • the square wave touch excitation signal is applied and detected according to the detection requirement;
  • FIG. 22b is the H segment of FIG. 22a.
  • the display electrode starts to apply the square wave touch excitation signal at the same fixed time in the frame blanking period to realize frame synchronization;
  • 22c is a diagram An enlarged view of the X segment (loading the excitation signal and detecting the time period) in 22b, after the frame synchronization is performed in the display frame blanking period, the touch excitation signal is applied, and the number of excitation signal pulses is also calculated, and each sampling is performed.
  • the detection is controlled on the number of touch excitation signal pulses of the same serial number to realize the synchronization of the number of touch excitation pulses; in the touch excitation signal pulse, each The time at which the sampled data is acquired is at a specific phase of the waveform of the touch excitation output terminal to achieve synchronization with the touch excitation waveform.
  • the touch excitation source 1810 is a sine wave signal. Since the 1830 and 1831 are capacitive loads, the waveform of the sinusoidal touch excitation source with the capacitive load is still at the touch signal sampling point. The sine wave, but the amplitude and phase change, the output waveform of the touch excitation source 1810 and the touch signal waveform of the touch signal sampling point are as shown in FIG.
  • the touch signal detection method uses a phase shift measurement method to compare phase shifts of a specific phase point of the touch signal sampling point 1841 on different frame blanking periods to obtain touch information;
  • a particular phase point refers to a particular phase point relative to the waveform of the output of the touch excitation source 1810.
  • the touch excitation source signal is used as the circuit source, and the branch circuit where the sampling resistor is located is an RC circuit in which 1830 and 1831 two capacitors are connected in parallel and then two resistors 1820 and 1821 are connected in series.
  • a touch excitation signal is applied to the circuit shown in FIG. 18, and the sine wave passes through the RC.
  • the loop will have a falling amplitude and a phase delay.
  • the coupling capacitor 1831 causes a change in C in the RC loop.
  • the sinusoidal zero-crossing point is measured at the touch signal sampling point relative to the output of the touch excitation source 1810.
  • the change in the zero-crossing time difference is used to determine whether the touch has occurred.
  • the change of the phase shift of the touch signal waveform at the sampling point of the touch signal is measured, and the measurement may be performed at the peak point of the sine wave or at other phase points.
  • the synchronization relationship here consists of three synchronization relationships: display frame synchronization, touch excitation pulse number synchronization, and touch excitation waveform phase synchronization.
  • No frame synchronization Each time the touch excitation signal is applied, it is a fixed time in the frame blanking period between two display frames; the number of excitation pulses is synchronized: from the start of applying the touch excitation signal to On the display electrode used by the touch sensing electrode, the number of touch excitation signal pulses is calculated, and the time at which the sampled data is acquired is at the same number of touch excitation signal pulses; the excitation waveform phase synchronization: the touch is measured The specific phase point of the touch signal waveform at the signal sampling point is compared with the same phase point of the waveform of the touch excitation source output: the phase shift information of the sine wave is all-phase, so as long as the same specific time is seen The phase point can be moved.
  • Figure 24a is a timing diagram of the time division multiplexing of the display screen.
  • the row electrode, the column electrode and the COM electrode of the display screen are in the display scanning time period, and the corresponding display signals are outputted, and the display scanning is performed sequentially, and the row electrodes in the display screen,
  • the sine wave excitation signal is loaded and detected according to the detection requirement;
  • FIG. 24b is the H segment of FIG. 24a.
  • the display electrode begins to apply a sine wave touch excitation signal at the same fixed time in the displayed frame blanking period to achieve frame synchronization
  • Figure 24c is an enlarged schematic view of the X segment (applying the touch excitation signal and detecting the time period) in Figure 24b. After the frame synchronization in the displayed frame blanking period, the sine wave touch excitation signal is applied, and the calculation is started.
  • the number of touch excitation signal pulses, each sampling detection is controlled by the number of touch excitation signal pulses of the same serial number, so as to achieve the same number of excitation pulses ;
  • the sine wave touch excitation signal pulse which, each time the sample data acquired at the same time have a particular phase point of the output end of the touch excitation waveform, to achieve synchronization with the touch excitation waveform phase control.
  • the fourteenth and the fifteenth embodiments use the instantaneous value measurement method to perform touch detection on the touch display 400 of FIG.
  • This instantaneous value measurement method is to detect the touch signal in a very short period of time at a specific phase point, and the main feature is that the detection speed is fast.
  • the three circuit structures for realizing the instantaneous value measurement touch signal detection are shown in FIG. 25, FIG. 26 and FIG.
  • the touch signal detection circuit structure is composed of a signal detection channel, a data sampling channel, and a data processing and timing control circuit.
  • the signal detection channel has a buffer, a first stage differential amplifying circuit and a second stage differential amplifying circuit; the data sampling channel has an analog to digital conversion circuit; the data processing and timing control circuit is a central processing unit having a data computing capability and a data output input interface (CPU, MCU), the central processing unit has control software and data processing software.
  • FIG. 25 is a structural diagram of a touch signal detecting circuit of an instantaneous value measuring method, 2510 is a signal of a touch signal sampling point, 2511 is a signal for detecting a reference point, a signal 2510 of a touch signal sampling point, and a detection reference point.
  • the signal 2511 is buffered by the buffer 2520 and the buffer 2521, respectively, as an input signal of the first stage differential amplifier 2522; the output of the first stage differential amplifier 2522 is used as one of the inputs of the second stage differential amplifier 2523, and the 2524 is adjusted.
  • a voltage output which serves as a reference potential, is coupled to the other input of the second stage differential amplifier 2523 for subtracting the bottom value of the output signal of the first stage differential amplifying circuit; the second stage differential amplifier 2523 is output to the analog to digital converter 2525,
  • the 2525 performs synchronous sampling under the control of the synchronous control signal 2530 outputted by the central processing unit (CPU, MPU) 2526, and the sampling conversion result is sent to the central processing unit (CPU, MPU) 2526, and then the central processing unit performs data processing and touch. Control judgment.
  • FIG. 26 is a structural diagram of a touch signal detecting circuit of an instantaneous value measuring method
  • 2610 is a signal of a touch signal sampling point
  • 2611 is a signal for detecting a reference point, a signal 2610 of a touch signal sampling point, and a detection reference point.
  • the signal 2611 is buffered by the buffer 2620 and the buffer 2621, respectively, as an input signal of the first stage differential amplifier 2622; the output of the first stage differential amplifier 2622 is used as one of the inputs of the second stage differential amplifier 2623, and the feedback adjustment simulation is performed.
  • the circuit 2624 uses the output of the second stage differential amplifier 2623 as a feedback input signal and automatically adjusts the output voltage as a reference potential, which is coupled to the other input of the second stage differential amplifier 2623 for subtracting the output signal of the first stage differential amplifying circuit.
  • the bottom value of the second stage differential amplifier 2623 is output to the analog-to-digital converter 2625, and the 2625 is synchronously sampled under the control of the synchronous control signal 2630 outputted by the central processing unit (CPU, MPU) 2626, and the sampled conversion result is sent to the central processing. (CPU, MPU) 2626, and then the central processing unit for data processing and touch judgment.
  • FIG. 27 is a structural diagram of a touch signal detecting circuit of an instantaneous value measuring method
  • 2710 is a signal of a touch signal sampling point
  • 2711 is a signal for detecting a reference point
  • a signal 2710 of a touch signal sampling point and a detection reference point.
  • the signal 2711 is buffered by the buffer 2720 and the buffer 2721, respectively, as an input signal of the first stage differential amplifier 2722; the output of the first stage differential amplifier 2722 is used as one of the inputs of the second stage differential amplifier 2723, the central processing unit (CPU, MPU) 2726 sends the adjustment data to the digital-to-analog converter 2724 according to the result of the touch operation, and the output voltage of the 2724 is used as the reference potential, and is connected to the other input of the second-stage differential amplifier 2723 for subtracting the first-stage differential amplification.
  • CPU, MPU central processing unit
  • the bottom value of the circuit output signal; the second stage differential amplifier 2723 outputs to the analog to digital converter 2725, 2725 is synchronously sampled under the control of the synchronous control signal 2730 outputted by the central processing unit (CPU, MPU) 2726, and the sampled conversion result is transmitted.
  • the central processing unit (CPU, MPU) 2726 To the central processing unit (CPU, MPU) 2726, and then the central processing unit for data processing and touch judgment.
  • the difference between the three instantaneous value measurement touch signal detection circuits shown in FIG. 25, FIG. 26 and FIG. 27 is as follows:
  • the scheme shown in FIG. 25 is a manual method for setting a reference potential to the secondary differential circuit, and the second differential circuit.
  • the basic adjustment capability is shown in Fig. 26.
  • the scheme shown in Fig. 26 is that the output signal of the secondary differential circuit is fed back to the second differential circuit as a reference potential through the analog circuit, and has an automatic tracking adjustment capability for the second differential circuit;
  • the plan is to centrally process The result of the operation is fed back to the secondary differential circuit as a reference potential by the digital-to-analog conversion circuit, and has an intelligent adjustment capability for the secondary differential circuit.
  • the resistance of the electrodes is generally above 2K.
  • the touch signal is shunted due to the input impedance of the detection circuit, and the input impedance of the detection circuit is The larger, the smaller the shunting effect on the touch signal.
  • the input impedance of the detection circuit is 2.5 times or more, the touch signal can reflect the touch action information, so the input impedance of the signal detection channel to the electrode line is required to be 5 ⁇ or 5 ⁇ or more, as shown in Figures 25, 26, and 27
  • a buffer is added between the amplifying circuit and the connection point of the electrode line on the touch screen to increase the input impedance of the detecting circuit.
  • the average value measurement method is to detect the touch signal in a certain period of time, and obtain an average value of the touch control signal as a measurement result.
  • the average measurement method is slower than the instantaneous value measurement method, its main feature is that it can eliminate some high-frequency interference, and the measurement data is more stable, which is beneficial to the judgment of touch.
  • a valid value is one of the average values.
  • the three circuit structures for realizing the touch signal detection by the average value measurement method are shown in Fig. 28, Fig. 29 and Fig. 30.
  • the structure of the touch signal detection circuit is composed of a signal detection channel, a data sampling channel, a data processing and a timing control circuit.
  • the signal detection channel has a buffer, a first-stage differential amplification circuit, an RMS measurement circuit and a second-stage differential amplification circuit;
  • the data sampling channel has an analog-to-digital conversion circuit;
  • the data processing and timing control circuit has a data operation capability and a data output input.
  • the central processing unit (CPU, MCU) of the interface, the central processing unit has control software and data processing software.
  • FIG. 28 is a structural diagram of a touch signal detecting circuit of an average value measuring method
  • 2810 is a signal of a touch signal sampling point
  • 2811 is a signal for detecting a reference point, a signal 2810 of a touch signal sampling point, and a detection reference point.
  • the signal 2811 is buffered by the buffer 2820 and the buffer 2821, respectively, and serves as an input signal of the first-stage differential differential amplifying circuit unit 2822; the first-stage differential differential amplifying circuit unit 2822 includes a frequency gating circuit, and the gating circuit is selected.
  • the pass frequency is the frequency of the excitation source touch signal, which gates the differential amplified output, the gated output is used as the input of the rms converter 2823, and the effective value of 2823 is output as the input of the second stage differential amplifier 2824.
  • the 2825 is a regulated voltage output that is connected as a reference potential to the other input of the second stage differential amplifier 2824 to subtract the bottom value of the 2823 rms output signal; the second stage differential amplifier 2824 outputs to the modulo
  • the converters 2826, 2826 perform simultaneous sampling under the control of the synchronous control signal 2830 output from the central processing unit (CPU, MPU) 2827. Sampling conversion result is sent to a central processing unit (CPU, MPU) 2827, and then performs data processing and touch determination by the central processor.
  • FIG. 29 is a structural diagram of a touch signal detecting circuit of an average value measuring method
  • 2910 is a signal of a touch signal sampling point
  • 2911 is a signal for detecting a reference point
  • a signal 2910 of a touch signal sampling point and a detection reference point.
  • the signal 2911 is buffered by the buffer 2920 and the buffer 2921, respectively, and is used as the first-stage differential differential amplifying circuit unit 2922.
  • the first stage differential differential amplifying circuit unit 2922 includes a frequency strobe circuit.
  • the strobe frequency of the strobe circuit is the frequency of the excitation source touch signal, and the strobe output is strobed.
  • the effective value of 2923 is output as an input of the second stage differential amplifier 2924;
  • the feedback adjustment analog circuit 2925 uses the output of the second stage differential amplifier 2924 as a feedback input signal and automatically adjusts the output voltage.
  • it is connected to the other input of the second stage differential amplifier 2924 for subtracting the bottom value of the RMS output signal of 2923;
  • the second stage differential amplifier 2924 is output to the analog to digital converter 2926, 2926 for central processing Device
  • CPU, MPU 2927 output synchronous control signal 2930 under the control of synchronous sampling, the sampling conversion result is sent to the central processing unit (CPU, MPU) 2927, and then the central processing unit for data processing and touch judgment.
  • FIG. 30 is a structural diagram of a touch signal detecting circuit of an average value measuring method
  • 3010 is a signal of a touch signal sampling point
  • 3011 is a signal for detecting a reference point
  • a signal 3010 of a touch signal sampling point and a detection reference point.
  • the signal 3011 is buffered by the buffer 3020 and the buffer 3021, respectively, and serves as an input signal of the first-stage differential differential amplifying circuit unit 3022.
  • the first-stage differential differential amplifying circuit unit 3022 includes a frequency gating circuit, and the gating circuit is selected.
  • the pass frequency is the frequency of the excitation source touch signal, which gates the differential amplified output, the gated output is used as the input of the rms converter 3023, and the RMS output of 3023 is used as the input of the second stage differential amplifier 3024. ;
  • CPU, MPU 3027 sends the adjustment data to the digital-to-analog converters 3025, 3025 according to the result of the touch operation, and the output voltage of the 3025 is used as a reference potential, and is connected to the other input terminal of the second-stage differential amplifier 3024 for subtracting the effective of 3023.
  • CPU, MPU central processing unit
  • the difference between the three average measurement method touch signal detection circuits shown in FIG. 28, FIG. 29 and FIG. 30 is as follows:
  • the scheme shown in FIG. 28 is a manual method for setting a reference potential to the secondary differential circuit, and the second differential circuit.
  • the basic adjustment capability is shown in Fig. 29.
  • the scheme shown in Fig. 29 is that the output signal of the secondary differential circuit is fed back to the second differential circuit as a reference potential through the analog circuit, and has an automatic tracking adjustment capability for the second differential circuit;
  • the solution is that the result of the central processor operation is fed back to the second differential circuit as a reference potential through the digital-to-analog conversion circuit, and the secondary differential circuit has an intelligent adjustment capability.
  • the resistance of the electrodes is generally above 2K.
  • the touch signal is shunted due to the input impedance of the detection circuit, and the input impedance of the detection circuit is The larger, the smaller the shunting effect on the touch signal.
  • the input impedance of the detection circuit is 2.5 times or more, the touch signal can reflect the touch action information, so the input impedance of the signal detection channel to the electrode line is required to be 5 ⁇ ⁇ or more, as shown in Figures 28, 29, and 30.
  • a buffer is added between the amplifying circuit and the connection point of the electrode line on the touch screen to increase the input impedance of the detecting circuit.
  • the touch display 400 shown in FIG. 4 uses a TFT-LCD, and the equivalent circuit of the measurement is as shown in FIG. 18.
  • the touch excitation source 1810 is a square wave signal. Since the 1830 and 1831 are capacitive loads, the square wave signal excited by the touch generates a charge and discharge waveform on the two capacitors.
  • the output waveform of the touch excitation source 1810 and the touch signal waveform of the touch signal sampling point 1841 are as shown in FIG. 21.
  • FIG. 21 is now re-marked as shown in FIG.
  • the touch signal detection method uses a time feature measurement method to measure a change in the time interval between two predetermined potentials during charging and discharging of the touch signal sampling point 1841 to obtain touch information.
  • the time ⁇ 423 between the two predetermined potentials V422 and V421 during the charging process of the waveform of the touch signal sampling point 1841 is measured, and the time ⁇ 424 between the two predetermined potentials V421 and V422 during the discharging process can reflect this.
  • the change in capacitive load When the finger touches the display, the coupling capacitance 1831 of the equivalent circuit of Fig. 18 is generated, changing the capacitive load of the circuit and the time constant.
  • the time interval ⁇ 423 and ⁇ 424 between the two established potentials are also changed.
  • the measurement time interval ⁇ 423 and ⁇ 424 change to obtain the touch information.
  • the predetermined potentials V421 and V422 select the two potentials of the sampling point 1841 during charging and discharging.
  • the circuit structure for realizing the time characteristic measurement touch signal detection is shown in FIG. 32 and FIG.
  • the touch signal detection circuit structure is composed of signal detection and data sampling channels, data processing and timing control circuits.
  • the signal detection and data sampling channel has a buffer, a digital-to-analog conversion circuit or a voltage-regulating output unit, a comparator, and a counter;
  • the data processing and timing control circuit is a central processing unit (CPU, a data processing input interface) MCU), the central processing unit has control software and data processing software.
  • 32 is a structural diagram of a touch signal detecting circuit of a time characteristic measuring method
  • 3210 is a signal of a touch signal sampling point
  • 3211 is a predetermined potential (V421), which is generated by a voltage adjusting output unit 3220
  • 3212 is an established
  • the potential (V422) is generated by the voltage adjustment output unit 3221; the signal 3210 of the touch signal sampling point is buffered and outputted through the buffer 3230, and compared with the predetermined potential of 3211 to enter the comparator 3232; the signal 3210 of the touch signal sampling point passes.
  • the buffer 3231 buffers the output and compares it with the predetermined potential of 3212 into the comparator 3233; the central processing unit (CPU, MCU) 3235 generates the count pulse signal 3240 of the counter 3234, and the output potential of the comparator 3233 is used as the start count of the counter 3234.
  • the signal, the output potential of the comparator 3232 is used as the stop count signal of the counter 3234; the reading of the counter 3234 after the count is stopped is read by the central processing unit (CPU, MCU) 3235, and the central processor (CPU, MCU) is read after the reading is completed.
  • 3235 sends a clear signal 3241 to clear the counter 3234, ready for the next reading, and Central central processor (CPU, MCU) 3235 performs data processing and touch determination.
  • 33 is a structural diagram of a touch signal detecting circuit of a time characteristic measuring method
  • 3310 is a signal of a touch signal sampling point
  • the central processing unit (CPU, MCU) 3327 outputs corresponding data by program preset or history detection and judgment.
  • the digital-to-analog converter 3320 outputs a predetermined potential 3311 (V421), and also outputs data to the digital-to-analog converter 3321 to output a predetermined potential 3312 (V422); the signal 3310 of the touch signal sampling point is buffered and output through the buffer 3322, and 3311
  • the predetermined potential enters the comparator 3324; the signal 3310 of the touch signal sampling point is buffered and outputted through the buffer 3323, and enters the comparator 3325 with the predetermined potential of 3312; the central processing unit (; CPU, MCU) 3327 generates the counting pulse of the counter 3326.
  • the signal 3330, the output potential of the comparator 3325 is used as the start count signal of the counter 3326, and the output potential of the comparator 3324 is used as the stop count signal of the counter 3326; the counter 3326 stops counting the reading by the central processing unit (CPU, MCU).
  • 3327 reads, after the reading is completed, the central processor (CPU, MCU) 3327 sends a clear signal 3331 to clear the counter 3326, ready for the next reading, and is processed by the central processing unit (CPU, MCU) 3327. And touch judgment.
  • the difference between the two types of time feature measurement touch signal detection shown in FIG. 32 and FIG. 33 is as follows:
  • the scheme shown in FIG. 32 is a manual method for setting two predetermined potentials V421 and V422 to the comparator;
  • the central processor sets two predetermined potentials V421 and V422 to the comparator, and the central processor outputs the corresponding data to the digital-to-analog conversion circuit through program preset or the previous measurement result, and outputs the output as a predetermined comparison potential for the predetermined comparison.
  • the settings of the potentials V421 and V422 have intelligent adjustment capabilities.
  • the touch excitation source 1810 is a sine wave signal. Since the 1830 and 1831 are capacitive loads, the waveform of the sinusoidal touch excitation source with the capacitive load is at the sampling point of the touch signal. It is also a sine wave, but the amplitude and phase change occur.
  • the output waveform of the touch excitation source 1810 and the touch signal waveform of the touch signal sampling point 1841 are as shown in FIG.
  • the touch signal detection method uses a phase shift measurement method to compare phase shifts of specific phase points on the touch signal sampling point 1841 on different frame blanking periods to obtain touch information. It can be seen that the influence of the touch capacitance can be reflected by measuring the change of the phase, and the phase change can also be reflected from the measurement time interval. The detection diagram of this time interval is also shown in Fig. 23, when the display screen is not touched by a finger. The presence of the distributed capacitor 1830 in FIG. 18 detects that the touch signal waveform on the touch signal sampling point 1841 has a phase delay relative to the waveform of the touch excitation source output terminal 1840; when the finger touches the display screen, FIG.
  • the coupling capacitor 1831 of the equivalent circuit is generated, which increases the capacitive load of the circuit.
  • the time T500 between the zero-crossing point on the touch signal sampling point 1841 and the zero-crossing point between the excitation sources becomes larger, that is, a further one is generated. Phase shift. Measurement time T500 changes to get touch information. Depending on the waveform of the touch excitation source, the potential corresponding to a particular phase point can be zero or other potential point.
  • the circuit structure for realizing the phase shift measurement touch signal detection is shown in FIGS. 34 and 35.
  • the touch signal detection circuit structure is composed of signal detection and data sampling channels, data processing and timing control circuits.
  • the signal detection and data sampling channel has a buffer, a digital-to-analog conversion circuit or a voltage-regulating output unit, a comparator, and a counter;
  • the data processing and timing control circuit is a central processing unit (CPU, a data processing input interface) MCU), the central processing unit has control software and data processing software.
  • FIG. 34 is a structural diagram of a touch signal detecting circuit of a phase shift characteristic measuring method, and 3410 is a sampling point of a touch signal.
  • the signal, 3411 is the signal for detecting the reference point
  • 3412 is the potential generated by the voltage adjustment output unit 3420 corresponding to a specific phase point
  • the signal 3410 of the touch signal sampling point is buffered and outputted through the buffer 3430, and the specific phase point of 3412
  • the corresponding potential enters the comparator 3432 for comparison
  • the signal 3411 of the touch signal sampling point is buffered and outputted through the buffer 3431, and the potential corresponding to the specific phase point of 3412 enters the comparator 3433 for comparison
  • the counter pulse signal 3440 of the counter 3434 is generated, the output potential of the comparator 3433 is used as the start count signal of the counter 3434, the output potential of the comparator 3432 is used as the stop count signal of the counter 3434; the counter 3434 counts the
  • the processor (CPU, MCU) 3435 reads, after the reading is completed, the central processing unit (CPU, MCU) 3435 sends a clear signal 3441 to clear the counter 3434, ready for the next reading, and is controlled by the central processing unit (CPU). , MCU) 3435 for data processing and touch judgment.
  • 35 is a structural diagram of a touch signal detecting circuit of a phase shift characteristic measuring method
  • 3510 is a signal of a touch signal sampling point
  • 3511 is a signal for detecting a reference point
  • a central processing unit (CPU, MCU) 3526 is preset according to a program.
  • the history detection determines to output the corresponding data to the digital-to-analog converter 3520, the potential 3512 corresponding to the specific phase point is the output potential of the digital-to-analog converter 3520; the signal 3510 of the touch signal sampling point is buffered and output through the buffer 3521, and 3512 The potential corresponding to the specific phase point enters the comparator 3523 for comparison; the signal 3511 of the touch signal sampling point is buffered and outputted through the buffer 3522, and the potential corresponding to the specific phase point of 3512 is entered into the comparator 3524 for comparison; the central processing unit (CPU) , MCU) 3526 generates a counter pulse signal 3530 of the counter 3525, the output potential of the comparator 3524 is used as a start count signal of the counter 3525, and the output potential of the comparator 3523 is used as a stop count signal of the counter 3525; The reading is read by the central processing unit (CPU, MCU) 3526, and the reading is completed by the center.
  • the difference between the two phase shift measurement touch signal detections shown in FIG. 34 and FIG. 35 is as follows:
  • the scheme shown in FIG. 34 is to manually set the potential corresponding to a specific phase point;
  • the scheme shown in FIG. 35 is processed by the central processing.
  • the digital analog-to-analog converter is used to set the potential corresponding to a specific phase point, and the central processing unit presets or calculates the previous measurement result and then feeds back the potential corresponding to the specific phase point through the digital-to-analog converter.
  • the settings have intelligent adjustment capabilities.
  • phase characteristics of the touch signal measured in this embodiment are also essentially one of the temporal characteristics.
  • the touch display 400 shown in FIG. 4 time division multiplexes the display electrodes to complete the touch function.
  • the touch display 400 is used as a touch sensing electrode line by using part or all of the N display electrode lines, and the touch detection is performed by a single channel sequential scanning detection method: the touch signal detecting circuit has a touch signal detection a channel or a data sampling channel, sequentially detecting the first, second, ..., and finally the Nth touch sensing electrode lines of the N touch sensing electrode lines in a scanning manner, thereby completing one
  • the entire detection process of the probe frame is as shown in FIG.
  • the first electrode, the i+1th, and the 2i+l of the N touch sensing electrodes are detected by scanning at a predetermined interval i. .., until the last Nth touch sensing electrode line, thus completing the entire detection process of a sounding frame.
  • the touch signal detection circuit has a detection channel or a data sampling channel, and touches
  • the control sensing electrode line is divided into several sections according to each area, and each part selects one or more touch sensing electrode lines as the touch sensing representative electrodes of the partition touch sensing electrode lines to perform touch detection together.
  • a good method is to connect all the touch sensing electrode lines in each partition as a touch sensing representative electrode; firstly, the touch sensing representative electrode is detected by the area to determine the area where the touch action occurs; and then there is touch Subdivided scan detection is performed in the area where the action occurs, and more specific touch information is obtained. The purpose of this method is to save time in touch detection.
  • the touch detection is performed by using a multi-channel sequential scanning detection method: the touch signal detection circuit has a plurality of touch signal detection channels and a plurality of data sampling channels, and all the touch sensing electrode lines are divided into a touch signal detection. The number of groups with the same number of channels, each touch signal detection channel is responsible for detection in a touch sensing electrode group.
  • FIG. 39 is a schematic diagram showing the scanning sequence of three touch signal detecting channels.
  • FIG. 40 is a schematic diagram showing the scanning sequence of three touch signal detecting channels.
  • each touch signal detection channel simultaneously performs coarse scan and fine scan detection in each group, and comprehensively detects the detection results of all touch signal detection channels to obtain full-screen touch information.
  • Figure 41 is a schematic diagram showing the scanning sequence of three touch signal detection channels.

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Description

一种可排除显示影响触控的触控显示器 技术领域
本发明涉及触控屏和平板显示器, 尤其涉及一种触控显示器。
背景技术
触控屏发展至今已广泛用于个人计算机、 智能电话、 公共信息、 智能家电、 工业控制 等众多领域。在目前的触控领域,主要有电阻式触控屏、光电式触控屏、超声波式触控屏、 平面电容式触控屏,近年来投射电容式触控屏发展迅速。但目前这些触控屏均具有各自的 技术缺点, 造成它们虽然在某些特殊场合已广为采用, 但难以在普通显示屏上推广应用。
显示屏与触控屏是对孪生产品,现有技术中,通常显示屏与触控屏各自独立承担显示 和触控任务。 目前这种分立式的具有触控功能的平板显示器以显示屏、显示驱动器、触控 屏、触控信号检测器、背光源等部件构成,触控屏有应用不同感测原理的电阻式、电容式、 电磁式、 超声波式和光电式等, 显示屏有无源液晶显示屏 (TN/STN-LCD)、 有源液晶显示 屏 (TFT-LCD)、 有机发光二极管显示屏 (OLED、 AM-OLED)、 等离子体显示屏 (PDP)、 纳 米碳管显示屏、 电子纸 (e- paper)等。带有触控屏的平板显示器是将分体的触控屏与显示屏 层叠在一起,通过触控屏探测到触摸点的平面位置,再使显示屏上的光标跟随触摸点定位。 触控屏与显示屏的层叠使得触控式平板显示器变厚变重成本增加;在触控屏置于显示屏前 面时,触控屏感测电极产生的反射又会使得显示不均匀和在强外界光环境下显示对比度的 下降, 影响显示效果。将触控板和显示屏集成为一体, 使具有触控功能的平板显示器变得 更加轻薄, 是人们努力的方向。
找出一种解决上述的结构复杂问题的方案, 提高具有触控功能的平板显示器的可靠 性、 改善显示效果、压缩厚度、 降低成本, 以简洁的方法实现平板显示器触控功能是必要 的。
申请号为 2006100948141、 名称为《触控式平板显示器》和申请号为 2006101065583、 名称为《具有触控功能的平板显示器》的中国发明专利说明书, 分别揭示了一种触控探测 电路与显示屏电极之间的连接方式,通过模拟开关或加载电路使显示屏电极或传输显示驱 动信号, 或传输并感测触控信号, 显示驱动和触控探测时分复用或同时共用显示屏电极, 显示屏电极既用于显示驱动又用于触控探测, 从而创新性地提出了"触控式平板显示器" 的概念。
申请号为 2009102035358、 名称为《一种触控式平板显示器的驱动实现》 的中国发明 专利说明书, 申请号为 2009101399060、 名称为 《一种触控式平板显示器的驱动实现》 的 中国发明专利说明书, 申请号为 200810133417X、 名称为《一种触控式平板显示器》的中 国发明专利说明书, 则又对触控式平板显示器做出了进一步的改进。。
上述中国专利所揭示的这类触控式平板显示器基本工作原理是, 利用显示屏上两组 相交的电极作为触控传感电极, 电极组的各条电极线连接触控激励源,触控激励源向电极 线施加交流或直流的触控激励信号。 当人的手指或其他触控物靠近或接触某条电极线时, 触控电路通过探测各条电极线触控信号变化的大小,从而找出手指或其他触控物在显不屏 上的位置。
这是一种全新的显示与触控二合为一式的触控探测技术, 具有显著的成本优势, 对 其改进后具有广阔的发展前景。本发明就是对其提出的在排除显示内容变化对触控信号检 测的影响方面的一种改进。
发明内容
本发明的目的是提供一种可排除显示影响触控的触控显示器,解决如何排除显示内容 不同对触控信号检测的影响的问题。
本发明提出一种可排除显示影响触控的触控显示器,包括有源液晶显示屏、显示驱动 电路、 触控电路, 以及使显示屏电极既用于显示驱动又用于触控探测的显示 /触控信号选 通输出电路或显示 /触控信号加载电路; 所述触控电路具有触控激励源和触控信号检测电 路; 所述显示 /触控信号选通输出电路使显示屏电极或与显示驱动电路连通传输显示驱动 信号, 或与触控探测电路连通传输触控信号, 显示驱动和触控探测时分复用显示屏电极; 所述显示 /触控信号加载电路使显示屏电极同时传输显示驱动信号和触控信号, 显示驱动 和触控探测同时共用显示屏电极;在有源液晶显示屏的至少一片基板上具有有源器件阵列 和连接有源器件阵列的行电极组、列电极组, 在显示屏的另一片基板上具有公共电极; 正 常显示时段结束后, 在显示屏部分或全部行列电极线上和公共电极上施加液晶预驱动信 号,液晶预驱动信号的大小是要让施加有液晶预驱动信号的行列电极线相对公共电极之间 所具有的电位差不小于液晶的饱和驱动电压,使施加有液晶预驱动信号的行列电极线与公 共电极之间的液晶分子处于确定的排列状态, 排除显示内容变化对触控信号检测的影响。
进一步地, 在本发明的优选实施例中:
所述在显示屏部分或全部行列电极线上和公共电极上所施加的液晶预驱动信号,是同 时或不同时施加在不同的行列电极线上; 在行列电极线上施加有液晶预驱动信号的时段 内, 在公共电极上也有施加液晶预驱动信号的时刻。
所述在显示屏部分或全部行列电极线上和公共电极上所施加的液晶预驱动信号,是在 对显示屏部分或全部行列电极线上和公共电极上施加液晶预驱动信号后,再对施加过液晶 预驱动信号的行列电极线施加触控信号, 并检测电极线上触控信号的变化。
所述在显示屏部分或全部行列电极线上和公共电极上所施加的液晶预驱动信号,是在 对行列电极线施加触控信号的同时,或在对行列电极线施加触控信号之后,对显示屏部分 或全部行列电极线上和公共电极上施加液晶预驱动信号;在施加液晶预驱动信号后,再检 测施加过液晶预驱动信号的电极线上触控信号的变化。
所述显示屏上的有源器件阵列是 TFT阵列,行列电极线分别连接 TFT的栅极和源极、 或分别连接 TFT的栅极和漏极, 对连接 TFT源极或漏极的列电极线具有同时施加液晶预 驱动信号的时段。
所述对显示屏部分或全部行列电极线上和公共电极上施加液晶预驱动信号,是在显示 屏上全部的或部分的与显示象素相连的有源器件处于截止状态的时段。
所述液晶预驱动信号是在显示屏上与显示象素相连的有源器件的导通状态时段施加。 所述液晶预驱动信号和触控信号是在显示屏上与显示象素相连的有源器件的导通状 态时段同时施加。
所述显示屏上的有源器件阵列是 TFT阵列, 在与显示象素相连的 TFT的导通状态时 段, 对连接 TFT源极或漏极的列电极线和公共电极施加液晶预驱动信号。
所述在行或列电极组上或公共电极上施加的液晶预驱动信号,是交流信号、直流信号、 交流和直流混合信号中的一种。
所述施加在显示屏同一电极上的液晶预驱动信号和触控信号是频率或波形相同的交 流信号。
所述液晶预驱动信号的频率是 10kHz或 ΙΟΚΗζ以上。
本发明与现有技术对比的有益效果是:
本发明所揭示的方式通过设置饱和预驱动过程,让液晶显示屏内行电极和 COM电极 之间、列电极和 COM电极之间的液晶分子排列趋于一致, 为触控探测提供了一个具有一 致性的测量环境, 避免了触控探测受显示内容的影响。
附图说明
附图 1是一种 TFT-LCD显示器典型的结构图;
附图 2是一种 TFT-LCD的显示子像素的结构示意图;
附图 3是一种 TFT-LCD液晶显示屏常规显示驱动的时序图;
附图 4是一种 TFT-LCD显示屏的触控显示器的结构图;
附图 5是一种时分复用显示屏电极的时序图;
附图 6是具体实施方式一的触控激励信号波形图; 附图 7是具体实施方式二的触控激励信号波形图;
附图 8是具体实施方式三的触控激励信号波形图;
附图 9是具体实施方式四的触控激励信号波形图;
附图 10是具体实施方式五的触控激励信号波形图;
附图 11是具体实施方式六的触控激励信号波形图;
附图 12是具体实施方式七、 方式八的时分复用显示屏电极的时序图;
附图 13是具体实施方式七、 方式八的触控激励信号波形图;
附图 14是在外场下正性液晶材料分子排列顺序图;
附图 15是在外场下负性液晶材料分子排列顺序图;
附图 16是具体实施方式九的时分复用显示屏电极时序图;
附图 17是具体实施方式十的时分复用显示屏电极时序图;
附图 18是手指触摸显示屏时的等效电路图;
附图 19是触摸所产生的触控信号泄漏电流 Δί随频率变化的曲线图;
附图 20是 COM电极设置在上基板玻璃上时,手指触摸显示屏时的等效电路图; 附图 21是触控激励信号为方波时,触控激励源和触控信号采样点的触控信号波形图; 附图 22a、 22b、 22c是触控激励信号为方波时, 触控探测的完整同步过程示意图; 附图 23是触控激励信号为正弦波时, 触控激励源和触控信号采样点的触控信号波形 附图 24a、 24b、 24c是触控激励信号为正弦波时, 触控探测的完整同歩过程示意图; 附图 25是一种瞬时值测量法的触控信号检测电路结构图;
附图 26是一种瞬时值测量法的触控信号检测电路结构图;
附图 27是一种瞬时值测量法的触控信号检测电路结构图;
附图 28是一种有效值测量法的触控信号检测电路结构图;
附图 29是一种有效值测量法的触控信号检测电路结构图;
附图 30是一种有效值测量法的触控信号检测电路结构图;
附图 31是触控激励信号为方波, 触控信号采样点触控信号的时间特征;
附图 32是一种时间特征测量法的触控信号检测电路结构图;
附图 33是一种时间特征测量法的触控信号检测电路结构图;
附图 34是一种相移测量法的触控信号检测电路结构图;
附图 35是一种相移测量法的触控信号检测电路结构图;
附图 36是一种单通道顺序扫描的触控检测方式检测顺序示意图;
附图 37是一种单通道间隔扫描的触控检测方式检测顺序示意图; 附图 38是一种单通道粗扫加细扫的触控检测方式检测顺序示意图;
附图 39是一种多通道顺序扫描的触控检测方式检测顺序示意图;
附图 40是一种多通道间隔扫描的触控检测方式检测顺序示意图;
附图 41是一种多通道粗扫加细扫的触控检测方式检测顺序示意图。
具体实施方式
本发明适用于包括具有行电极和列电极的液晶显示屏 (LCD)、有机发光二极管显示屏 (OLED、 AM OLED)、 等离子体显不屏 (PDP)、 纳米碳管显不屏、 电子纸 (e-paper)等平板 显示器。
本说明书的内容以有源液晶显示器的典型代表薄膜场效应晶体管液晶显示器 (Thin Film Transistor LCD, TFT-LCD)为对象进行阐述。
薄膜场效应晶体管液晶显示屏是有源矩阵液晶显示器 (AM LCD)的典型代表, 它以基 板上的薄膜场效应晶体管 (TFTM乍为开关器件。 TFT-LCD显示器典型的一个结构如图 1所 示: 110是 TFT液晶屏; 120是液晶屏水平方向扫描行电极, 121、 122、 ...、 12m- K 12m 是扫描电极线 (行电极线); 130是液晶屏垂直方向数据列电极, 131、 ...、 13η是数据电极 线 (列电极线); 140是公共电极 (COM电极), 公共电极连接的电位是作为液晶显示像素的 参考电位; 150是液晶屏上的薄膜晶体管 TFT, 其栅极 (Gate)连接至水平方向扫描线, 源 极 (Source)连接至垂直方向的数据线, 漏极 (Drain)则连接至显示像素电极; 160是显示像 素对应的液晶分子盒, 在电气上等效于一个电容, 这个电容一般定义为 CLC; 170是存储 电容 (Capacitance Storage , Cs), 用来存储显示像素的信息; 180是公共电极电压源, 负 责产生公共电极参考电压 (Vcom Reference); 181是 TFT-LCD的栅极电极 (行电极;)驱动器 (Gate Driver), 用来驱动水平方向扫描线; 182是 TFT-LCD的源极电极 (列电极)驱动器 (Source Driver),用来驱动垂直方向数据线; 183是时序控制器 (Timing Controller)负责接收 来自影像信号处理芯片的 RGB数据、 时钟信号 Clock、 水平同步 Hsync和垂直同步信号 Vsync, 并将这些信号转换, 用于控制源极 (列电极)驱动器 (Source Driver)和栅极(行电极) 驱动器 (Gate Driver)协同工作。
一个显示像素一般由三个显示红、绿、蓝三种原色的子像素组成。一个显示子像素的 结构示意图如图 2所示: Gi代表水平方向行扫描电极线, 也称为行驱动电极线或栅驱动 电极线, Gi上的电位是 Vg; Sj代表垂直方向列数据电极线, 也称为列驱动电极线或源驱 动电极线, Sj上的电位是 Vs; Dij代表 TFT连接显示像素的端子, 称为漏极, Dij上的电 位是 Vd, 也称为像素电位; 每个显示像素均配置一个半导体开关器件 -薄膜基板上场效应 晶体管 (TFT), 可以通过脉冲直接控制选通进行显示扫描, 因而每个像素相对独立。 TFT 的栅极 (Gate)与源极 (Source)间的电压为 Vgs, TFT的栅极 (Gate) 与漏极 (Drain) 间的 电压为 Vgd。 薄膜场效应晶体管 (TFT)有 MOS型和 PMOS型两种。 目前绝大部分的 TFT-LCD中所使用的薄膜场效应晶体管, 是采用非晶硅 (amorphous silicon, a-Si)制程, 其栅极绝缘层是氮化硅 (SiNx), 容易攫取正电荷, 要在非晶硅半导体层中形成沟道, 恰好 利用氮化硅中的正电荷来帮助吸引电子以形成沟道, 因此使用非晶硅制程的 TFT多为 MOS型。本说明书的内容主要是以 NMOS型薄膜场效应晶体管为代表进行阐述, PMOS 型薄膜场效应晶体管可遵循相通的原理, 不再单独列举表述。
TFT-LCD 液晶显不屏常规显不驱动的时序如图 3 所不: 在显不扫描时间段 (Display Time)里面, 显示驱动电路对行电极执行顺序扫描显示, 列电极、 COM电极配合输出相应 的显示信号,让显示屏处于显示状态; 每两个显示扫描时间段之间会有一个帧消隐时间段 (Vertical Blanking Time),这个时间段里面显示屏不执行显示驱动,显示驱动电路对行电极 扫描停止, 对所有的行电极均输出 TFT的非选择信号, 列电极、 COM电极保持原来的输 出态或者某预设输出信号, TFT 处于截止状态。 本发明中的时分复用显示屏电极技术方 案就是利用这个帧消隐时间段作为复用显示屏电极为检测电极的时间段。
一种触控电路通过控制显示驱动电路和触控电路协同工作,让显示屏电极或与显示驱 动电路连通传输显示驱动信号、或与触控电路连通传输触控信号,显示驱动和触控探测时 分复用显示屏电极。在显示时段, 显示屏电极连通显示驱动电路传输显示驱动信号, 显示 屏处于显示态。在触控探测时段, 显示屏电极连通触控电路传输触控信号, 并分别检测流 经各条行电极线和各条列电极线的触控信号的变化,以触控信号变化达到某设定条件的行 电极线和列电极线为被触电极线。由探测到的被触行电极线和被触列电极线的交叉点,确 定出被触点位置。
本发明实施例所列举的具体实施方式十六到方式十九揭示了相关的触控信号检测电 路结构。
除此之外,本发明实施例所列举的具体实施方式一到方式六是通过选择合理的触控激 励信号方案, 以避免触控激励信号影响显示效果的例子,具体实施方式七到方式十提出了 避免显示影响触控的几种解决方案,具体实施方式十一到方式十三揭示了触控激励信号频 率的选择要求,具体实施方式十四和方式十五揭示了触控探测时,对触控信号进行检测与 所施加的触控激励信号的同步关系,具体实施方式二十到方式二十三揭示了多种单通道和 多通道的触控检测扫描方式和顺序。这些实施例是对触控电路其余方面的改进,其采用与 否不影响本发明技术方案的实现, 不影响本发明的保护范围。
以 TFT-LCD为显示屏的触控显示器 400的电气连接关系如图 4所示。包括 TFT-LCD 显示屏 410; TFT-LCD显示屏水平方向的扫描行电极 420, 具有行电极线 421、 ...、 42m; TFT-LCD显示屏垂直方向的数据列电极 430, 具有列电极线 431、 ...、 43n; TFT-LCD显 示屏的公共电极层 (COM电极 )440; 1?1^-!^0显示屏上的薄膜场效应晶体管1?1 450, 其 栅极 (Gate)连接至水平方向扫描行电极线, 源极 (Source)连接至垂直方向的数据列电极线, 漏极 (Drain)则连接至像素电极; 显示像素对应的液晶盒 460, 在电气上等效于一个电容, 这个电容一般定义为 CLC; 存储电容 (Capacitance Storage, Cs)470, 用来存储像素的显示 信息; COM电极的显示驱动电路 480,触控探测状态时用于 COM电极的触控激励源 481, COM电极的 COM信号选通输出电路 482; 行电极的显示扫描驱动电路 483, 行电极的触 控电路 (具有触控激励源和触控信号检测电路) 484,行电极的行信号选通输出电路 485; 列 电极的显示数据驱动电路 486, 列电极的触控电路 (具有触控激励源和触控信号检测电 路) 487, 列电极的列信号选通输出电路 488; 时序控制器 (Timing Controller)489等。 显示 扫描驱动电路 483与触控电路 484通过行信号选通输出电路 485连接到行电极 420;显示 数据驱动电路 486与触控电路 487通过列信号选通输出电路 488连接到列电极 430; COM 显示驱动电路 480与触控激励源 481通过 COM信号选通输出电路 482连接到 COM电极 440。
时序控制器 489接收来自影像信号处理芯片的 RGB数据、 时钟信号 Clock、 水平同 步 Hsync和垂直同步信号 Vsync, 并控制连接栅极的行显示驱动电路 483、 连接源极的列 显示驱动电路 486和连接公共电极的 COM显示驱动电路 480协同工作;也控制连接源极 的行触控电路 484、 连接栅极的列触控电路 487和连接公共电极的 COM触控激励源 481 协同工作; 并让触控显示器内的行选通电路 485、 列选通电路 488和 COM信号选通输出 电路 482使显示屏电极或与显示驱动电路连通传输显示驱动信号、或与触控电路连通传输 触控信号, 显示驱动和触控探测时分复用显示屏电极。
在显示时段, 触控显示器 400内的行选通电路 485、 列选通电路 488和 COM信号选 通输出电路 482使显示屏行电极 420、 列电极 430和 COM电极 440, 分别连通行显示驱 动电路 483、 列显示驱动电路 486和 COM显示驱动电路 480传输显示驱动信号, 显示屏 410处于显示态。
在触控探测时段, 触控显示器 400内的行选通电路 485、 列选通电路 488和 COM信 号选通输出电路 482使显示屏行电极 420、 列电极 430和 COM电极 440, 分别连通行触 控电路 484、 列触控电路 487和 COM触控激励源 481传输触控信号, 并分别检测流经各 条行电极线和各条列电极线的触控信号的变化,显示屏行列电极切换作为触控感应电极使 用;以行触控电路 484和列触控电路 487检测到流经的触控信号变化达到某设定条件的行 电极线和列电极线为被触电极线。由探测到的被触行电极线和被触列电极线的交叉点,确 定出触摸点在显示屏 410上的位置。
图 4示意的是典型的触控显示器的结构,下面对具体实施方式的说明均建立在这个结 构的基础上。
具体实施方式一
图 4所示的触控显示器 400, 显示屏电极时分复用方案的时序如图 5所示。 以每两次 显示帧之间的帧消隐时间段作为触控探测时段,这个时间段里面显示屏电极切换为触控感 应电极使用, 在显示屏电极上施加触控激励信号, 并检测显示屏电极上触控信号的变化。
触控激励源为有直流底值或没有直流底值的方波信号源。 在触控探测时, 对如图 2 所不 TFT的 Gi, Sj, COM三个电极分别施加如图 6所不触控激励信号, 所施加的这三个 触控激励信号都是有直流底值或没有直流底值的方波,其频率相同且相位一致。在显示屏 电极从显示状态切换到触控探测状态时,首先让对电极 Gi与电极 Sj施加的触控激励信号 的瞬时电位差 Vgs=Vg-Vs低于让 TFT处于截止状态的截止电压; 其次再让对 COM电极 和电极 Gi施加合适的触控激励信号,使像素电极电位 Vd与 COM电极电位 Vcom的平均 值均保持不变, 并使像素电位 Vd符合 Vgd=Vg-Vd的瞬时电位差均低于让 TFT处于截止 状态的截止电压这一要求, 保证 Vgs和 Vgd均低于让 TFT处于截止状态的截止电压, 从 而确保了 TFT在触控探测状态下能保持有效截止, 并维持了显示像素的电压, 让显示效 果不受触控探测的影响。
触控激励源选择为有直流底值或没有直流底值的方波信号源,且这些方波信号源的频 率和相位一致, 跳变的幅度也一致, 使 TFT的 Gi, Sj , COM三个电极施加的激励信号的 差值为恒定的直流电平,事实上触控检测时可以采用结构简便的检测电路就能得到良好的 检测效果, 并且信号源的产生非常方便, 有较高的实用价值。
具体实施方式二
本实施例与实施例一的不同在于: 所施加的这三个触控激励信号(如图 7所示)的频 率是不相同的。
具体实施方式三
本实施例与实施例一和实施例二的不同在于:所施的这三个触控激励信号都是有直流 底值或没有直流底值的方波, 其频率相同但相位不一致,如图 8所示。
具体实施方式四
本实施例与实施例一至实施例三所不同的是:在触控探测时,如图 2所示 TFT的 Gi, Sj, COM三个电极分别施加如图 9所示触控激励信号, 所施加的三个触控激励信号都是 有直流底值或者没有直流底值的正弦波 (注意实施例一至三为方波而非正弦波), 其频率 相同和相位一致。
具体实施方式五
本实施例与实施例一至实施例四所不同的是,在触控探测时,如图 2所示 TFT的 Gi, Sj, COM三个电极分别施加如图 10所示触控激励信号, 所施加的三个触控激励信号都是 有直流底值或者没有直流底值的正弦波,频率和相位都相冋,但波形交流部分的幅值是不 同的。
具体实施方式六
本实施例与实施例一至实施例五所不同的是, 在触控探测时, 对如图 2所示 TFT的 Gi, Sj, COM三个电极分别施加如图 11所示触控激励信号, 这种激励信号的组合不使像 素电极电位 Vd与 COM 电极电位 Vcom的平均值均保持不变, 但可以令两者的电位差 Vd-Vcom的平均值保持不变, 也能让显示效果不受触控探测的影响。
具体实施方式七
图 4所示的触控显示器 400, 显示器采用 TFT-LCD, TFT-LCD采用正性液晶材料。 液晶材料介电系数各向异性的特征,使液晶盒内各处分布电容随各处液晶分子的排列而变 化。 TFT-LCD 内各处液晶分子的排列取决于该处驱动电压所累积的有效值, 不同时刻不 同位置累积的驱动电压有效值不同, 液晶分子排列就不同, 分布电容也不同, 进行触控探 测的测量环境就不同。 对 TFT-LCD施加驱动电压时, 液晶分子排列状态因驱动电场的作 用而一致趋向平行于电场的方向。
显示电极时分复用方案的又一时序如图 12所示。 以每两次显示帧之间的帧消隐时间 段作为触控探测时段。 在这一时间段里面, 先同时对显示屏所有行电极线 Gi和列电极线 Sj施加一个饱和的预置驱动 (预驱动, pre-driving;), Gi、 Sj和 COM三个电极上的信号波 形如图 13所示,触控激励信号为有直流底值或没有直流底值的正弦波。 Gi-Sj间的电位差 Vgs在 -10.5V到 -17V之间,低于让 TFT处于截止状态的截止电压,避免影响显示; Gi-COM 间的电位差 Vgc在 -10.5V到 -12V之间、 Sj-COM间的电位差 Vsc是 5V, 都超过液晶分子 的饱和驱动电压。在所施加的饱和驱动电压的作用下, 液晶显示屏内行电极和 COM电极 之间的液晶分子、列电极和 COM电极之间的液晶分子, 排列方向都一致迅速转向趋向平 行于电场的方向。 如图 14所示, 给正性液晶材料分子施加电场 E时, 液晶分子的排列平 行于电场方向的排列状态。再分别对显示屏行电极线 Gi和列电极线 Sj施加触控激励信号, 并分别检测流经各条行电极线和各条列电极线的触控信号的变化;之前的饱和预驱动电压 使液晶分子排列一致,排除了液晶材料介电系数各向异性导致的分布电容的变化,检测各 条行电极线上和各条列电极线上触控信号的变化时,不同时刻不同位置上的测量环境趋向 于一致, 有利于触控探测结果的稳定性和一致性。
对液晶外加电场时, 由于液晶分子为无极性分子, 如图 14液晶分子的排列不会受电 场正负方向的影响,所以在预驱动环节里电极上的瞬时电压可正可负,只要保持对液晶的 饱和驱动即可。 所以施加在显示屏同一电极上的预驱动信号和触控激励信号的波形或频 率、 幅值都可以是相同的, 甚至将预驱动信号和触控激励信号采用同一信号。
具体实施方式八
与实施例七不同的是, 本例中 TFT-LCD采用负性液晶材料,如图 15所示。
具体实施方式九
图 4所示的触控显示器 400, 显示器采用 TFT-LCD, 由于液晶显示器的响应速度相 对较低, 在显示高速画面时, 容易存在残影、 拖尾现象, 为了解决这一问题, 目前的一种 解决方案是提高显不的帧频, 在每一个显不帧后面插入一个"黑帧", 让"黑帧"阻断之前显 示内容的残影。 所谓黑帧就是在这一帧内, 在 TFT处于导通的状态下, 通过列电极 Sj对 显示像素电极施加一个饱和驱动电压,让显示像素内液晶分子的排列一致处于与所加电场 垂直或平行的方向。在显示像素内液晶分子排列处于一致的情况下,液晶显示屏内列电极 和 COM电极之间液晶分子的排列也将是一致的。 由于行电极是扫描电极, 各行电极上的 电压有效值是一样的, 在列电极和 COM电极之间液晶分子排列处于一致的情况下, 各行 电极上的分布电容就基本是一致的。
显示电极时分复用方案的时序如图 16所示。在黑帧之后才分别对显示屏行电极线 Gi 和列电极线 Sj施加触控激励信号, 并分别检测流经各条行电极线和各条列电极线的触控 信号的变化。利用黑帧让液晶分子排列处于一致,排除了液晶材料介电系数各向异性导致 的分布电容的变化,检测各条行电极线上和各条列电极线上触控信号的变化时,不同时刻 不同位置上的测量环境趋向于一致, 有利于触控探测结果的稳定性和一致性。
具体实施方式十
图 4所示的触控显示器 400, 显示器采用 TFT-LCD, 与实施例九相同之处在于, 也 在每一个显示帧后面插入一个"黑帧", 让"黑帧"阻断之前显示内容的残影。
与实施例九不同的是, 显示电极时分复用方案的再一时序如图 17所示。 在正常显示 帧之后和黑帧之后都分别对显示屏行电极线 Gi和列电极线 Sj施加触控激励信号,并分别 检测流经各条行电极线和各条列电极线的触控信号的变化。这样, 既充分地利用了显示帧 间的帧消隐时间,在每一帧消隐时间都将显示屏电极切换为触控感应电极使用;又利用黑 帧液晶分子排列一致,排除液晶材料介电系数各向异性导致的分布电容的变化;综合判断 来消除液晶分子排列不一致对检测环境的影响。
具体实施方式 ^一
图 4所示的触控显示器 400, 显示器采用 TFT-LCD, 玻璃基板厚度为 0.3mm。 当人 的手指触摸显示屏表面时,手指通过基板玻璃片与显示屏电极间形成一个耦合电容,等效 电路如图 18所示。 1810是对显示屏电极提供触控激励信号的触控激励源, 1820是触控电 路内触控信号检测电路的采样电阻, 1821 是一组作为触控感应电极使用的显示屏电极的 等效电阻, 1830 是一组作为触控感应电极使用的显示屏电极相对显示屏内其他电极的分 布电容, 1831是手指与一组作为触控感应电极使用的显示屏电极间的耦合电容, 1832是一 组作为触控感应电极使用的显示屏电极与 COM电极之间的电容。
通常, 手指与一组作为触控感应电极使用的显示屏电极间的重叠宽度在 5mm以下, 基板玻璃厚度为 0.3mm, 耦合电容 1831就大约为 10pF; 对于通常的 TFT-LCD采样电阻 1820和等效电阻 1821之和约为 30ΚΩ, 作为触控感应电极使用的显示屏电极上的触控信 号部分地从耦合电容 1831泄漏出去到手指; 当触控激励源输出 Vrms=5V的正弦波时,耦 合电容 1831导致的泄漏电流 Δί随触控激励源频率变化的关系如图 19所示。 触控激励信 号的频率对耦合电容 1831的容抗构成主要的影响, 而容抗不同, 电流从手指泄漏出去的 触控信号的大小就不同。 频率太低, 耦合电容 1831容抗太小, 触控显示器 400对触控物 的触控不敏感,容易产生触控的漏判断。触控激励信号的频率选择对触控探测可靠性的影 响较大, 特别是当显示器前再加有保护面壳的情况下。
从图 19可以看出, 在实际的实验结果中, 触控激励源的频率低于 ΙΟΚΗζ时, 泄漏电 流 Ai较小, 与环境噪声比较不够明显难于区分, 将触控激励源频率设置在 ΙΟΚΗζ或以上 时, 才是利用显示屏电极作为触控感应电极使用的合理电路参数。
具体实施方式十二
图 4所示的触控显示器 400, 显示器采用 TFT-LCD, 玻璃基板厚度为 0.3mm。 当液 晶屏的 COM电极设置在朝向操作者的上基板玻璃上时, COM电极会在行电极和列电极 与操作者之间形成一定的屏蔽效果。手指与显示屏 COM电极间形成一个耦合电容, COM 电极与一组作为触控感应电极使用的显示屏电极间又存在耦合电容, 等效电路如图 20所 示。 2010是对显示屏电极提供触控激励信号的触控激励源, 2020是触控电路内触控信号 检测电路的采样电阻, 2021是一组作为触控感应电极使用的显示屏电极的等效电阻, 2030 是一组作为触控感应电极使用的显示屏电极相对显示屏内其他电极的分布电容, 2031 是 COM电极与一组作为触控感应电极使用的显示屏电极间的耦合电容, 2032是手指与显示 屏 COM电极间的耦合电容, 2040是激励源和 COM电极之间的等效电阻。
通常, 手指与一组作为触控感应电极使用的显示屏电极间的重叠宽度在 5mm以下, 基板玻璃厚度为 0.3mm, 耦合电容 2032就大约为 10pF; 对于通常的 TFT-LCD采样电阻 2020和等效电阻 2021之和约为 30ΚΩ。 人的手指触摸触摸显示屏表面时, 由于耦合电容 2031和 2032的存在,作为触控感应电极使用的显示屏电极上的触控信号部分地从耦合电 容 2031流到 COM电极, 再从 COM电极与手指的耦合电容 2032部分泄漏出去到手指。 选用高频的触控激励信号时, 从耦合电容 2031和 2032泄漏的电流 Δί就较大, 触控信号 穿透 COM电极屏蔽的能力就较强, 可获得比较好的触控探测能力。 具体实施方式十三
图 4所示的触控显示器 400, 显示器采用 TFT-LCD。 液晶材料介电系数各向异性的 特征, 使液晶盒内各处分布电容随各处液晶分子的排列而变化。 TFT-LCD 内各处液晶分 子的排列取决于该处驱动电压所累积的有效值,不同时刻不同位置累积的驱动电压有效值 不同, 液晶分子排列就不同, 分布电容也不同, 进行触控探测的测量环境就不同。但液晶 材料介电系数的各向异性存在随频率变化的色散效应,通常在 500KHZ或以上电信号的作 用下, 其介电系数的各向异性基本不能体现。
对显示屏行电极线 Gi和列电极线 Sj施加频率在 1MHz或以上的触控激励信号,并分 别检测流经各条行电极线和各条列电极线的触控信号的变化。 虽然 TFT-LCD的不同位置 上液晶分子的排列不尽一致, 但由于液晶材料介电系数的各向异性的色散效应, 对于 1MHz或以上的触控激励信号,仍排除了液晶材料介电系数各向异性导致的分布电容的变 化,检测各条行电极线上和各条列电极线上触控信号的变化时,不同时刻不同位置上的测 量环境趋向于一致, 有利于触控探测结果的稳定性和一致性。
具体实施方式十四
图 4所示的触控显示器 400, 显示器采用 TFT-LCD。 实际进行触控探测时, 通常是 以电压信号为检测对象来进行测量。测量的等效电路如图 18所示。 1810是对显示屏电极 提供触控激励信号的触控激励源, 1820是触控电路内触控信号检测电路的采样电阻, 1821 是一组作为触控感应电极使用的显示屏电极的等效电阻, 1830 是一组作为触控感应电极 使用的显示屏电极相对显示屏内其他电极的分布电容, 1831 是手指与一组作为触控感应 电极使用的显示屏电极间的耦合电容, 1832是一组作为触控感应电极使用的显示屏电极与 COM电极之间的电容, 1841 是测量触控信号电压变化的触控信号采样点, 1840是测量 触控信号电压变化的检测参考点, 这里是选择触控激励源 1810的输出端作为参考点, 事 实上还可以选择其它的电位点为参考点, 如触控电路的地端、或触控电路的正电源端、或 触控电路的负电源端、或对比电路中的一点、或触控屏上另一组电极线等都能有不错的检 测效果。 触控激励源 1810为方波信号, 由于 1830和 1831是电容负载, 触控激励的方波 信号在这两个电容上出现充放电波形。 触控激励源 1810 的输出波形和触控信号采样点 1841的触控信号波形如图 21所示。
本实施方式对触控信号的检测方法采用瞬时值测量法, 测量触控信号采样点 1841在 某一特定相位点上的电位,比较不同的帧消隐时间段内所检测到的这个特定相位点电位的 变化, 来获取触控信息; 所述的某一特定相位点是指相对于触控激励源 1810输出端波形 的特定相位点。 图 18 所示电路以激励源信号为电路源、 采样电阻所在的支路上是 1830 和 1831两个电容并联再与 1820和 1821两个电阻串联的 RC回路。 在触控探测时段, 对 图 18所示电路施加触控激励信号, 电路就会对电容产生充放电过程。 图 21中 T1和 T2 段为适合釆样的相位区间, 在触控信号采样点 1841上 T1 的相位区间是电容开始充电到 充电完成的时间段, T2的相位区间是电容开始放电到放电完成的时间段。
为确保证每一次对触控信号的检测都处于相对于触控激励源 1810输出端波形的特定 相位点上, 需要保持严格的一系列的同步关系。这里的同步关系由三项同歩关系组成: 显 示帧同步、触控激励脉冲数同步、触控激励波形相位同步。 显示帧同步: 每次开始施加触 控激励信号都是在两次显不帧之间的帧消隐时间段内的某一固定时刻; 激励脉冲个数同 步:从开始施加触控激励信号到作为触控感应电极使用的显示屏电极上,开始计算触控激 励信号脉冲数,每次获取采样数据的时刻都是在相同序号的触控激励信号脉冲数上;激励 波形相位同步: 每次获取采样数据的时刻都处在触控激励源输出端波形的特定相位点上, 而这个特定相位点的位置选择在 T1或 T2这两个相位区间内。 一个完整的同步过程如图 22a、 图 22b、 图 22c所示。 图 22a是显示屏时分复用的时序图, 显示屏的行电极、 列电 极、 COM电极在显示扫描时间段里面, 配合输出相应的显示信号, 顺序进行显示扫描, 而在显示屏的行电极、 列电极、 COM电极在帧消隐时间段(H段和 K段) 内复用在触控 检测态时, 按检测要求施加方波触控激励信号并进行检测; 图 22b是图 22a中 H段和 K 段(帧消隐时间段)的放大示意图, 如图 22b所示显示屏电极在帧消隐时间段内的同一固 定时刻开始施加方波触控激励信号, 实现帧同步; 图 22c是图 22b中 X段 (加载激励信 号并检测时间段)的放大示意图, 在显示帧消隐时间段里面经过帧同步后, 开始施加触控 激励信号, 同时也开始计算激励信号脉冲个数,每次采样检测都是控制在相同序号的触控 激励信号脉冲数上, 以实现触控激励脉冲个数同步; 在此触控激励信号脉冲里面, 每次获 取采样数据的时刻都处在触控激励输出端波形的某特定相位上,以实现与触控激励波形相 位的同步。
具体实施方式十五
与实施例十四不同的是, 触控激励源 1810为正弦波信号, 由于 1830和 1831是电容 负载, 正弦波的触控激励源带上电容负载后, 在触控信号采样点上的波形还是正弦波, 但 发生了幅度和相位的变化, 触控激励源 1810的输出波形和触控信号采样点的触控信号波 形如图 23所示。
本实施方式对触控信号的检测方法采用相移测量法,比较不同的帧消隐时间段上触控 信号采样点 1841某一特定相位点的相位移动, 来获取触控信息; 所述的某一特定相位点 是指相对于触控激励源 1810输出端波形的特定相位点。图 18所示以触控激励源信号为电 路源、采样电阻所在的支路上是 1830和 1831两个电容并联再与 1820和 1821两个电阻串 联的 RC回路。 在触控探测时段, 对图 18所示电路施加触控激励信号, 正弦波通过 RC 回路会发生幅值的下降和相位的延迟; 手指触摸显示屏时, 耦合电容 1831引起了 RC回 路中 C的变化, 在触控信号采样点测量正弦波过零点相对触控激励源 1810输出端波形过 零点时间差的变化,来判断触控是否发生。测量触控信号采样点上触控信号波形相位移动 的变化, 也可以在正弦波的峰值点上或其他相位点上进行测量。
同样, 为确保每一次对触控信号的检测都处于相对于触控激励源 1810输出端波形的 特定相位点上,需要保持严格的一系列的同步关系。这里的同步关系由三项同步关系组成: 显不帧同步、触控激励脉冲数同步、触控激励波形相位同步。 显不帧同步: 每次开始施加 触控激励信号都是在两次显示帧之间的帧消隐时间段内的某一固定时刻;激励脉冲个数同 步:从开始施加触控激励信号到作为触控感应电极使用的显示屏电极上,开始计算触控激 励信号脉冲数,每次获取采样数据的时刻都是在相同序号的触控激励信号脉冲数上;激励 波形相位同步:将测量触控信号采样点上触控信号波形的特定相位点,与触控激励源输出 端波形相同相位点进行时间的比较: 正弦波的相移信息是全相位的,故只要每次都是看同 一个特定相位点的移动即可。一个完整的同步过程如图 24a、 图 24b、 图 24c所示。 图 24a 是显示屏时分复用的时序图, 显示屏的行电极、 列电极、 COM电极在显示扫描时间段里 面, 配合输出相应的显示信号, 顺序进行显示扫描, 而在显示屏的行电极、列电极、 COM 电极在显示的帧消隐时间段 (H段和 K段) 内复用在触控检测态时, 按检测要求加载正 弦波激励信号并进行检测; 图 24b是图 24a中 H段和 K段 (显示的帧消隐时间段) 的放 大示意图,如图 24b所示显示屏电极在显示的帧消隐时间段内的同一固定时刻开始施加正 弦波触控激励信号, 实现帧同步; 图 24c是图 24b中 X段 (施加触控激励信号并检测时 间段)的放大示意图, 在显示的帧消隐时间段里面经过帧同步后, 开始施加正弦波触控激 励信号, 同时也开始计算触控激励信号脉冲个数,每次采样检测都是控制在相同序号的触 控激励信号脉冲数上, 以实现激励脉冲个数同步; 在此正弦波触控激励信号脉冲里面, 每 次获取采样数据的时刻都处在触控激励输出端波形的相同的某特定相位点上,以实现与触 控激励波形相位的同步。
具体实施方式十六
具体实施方式十四和方式十五都是用瞬时值测量法,来对图 4的触控显示器 400进行 触控探测。这种瞬时值测量法是在特定相位点的极短时间段内进行对触控信号的检测,其 主要特点就是检测速度快。 实现瞬时值测量法触控信号检测的三种电路结构如图 25、 图 26和图 27所示。触控信号检测电路结构都是由信号检测通道、数据采样通道和数据处理 和时序控制电路组成。信号检测通道具有缓冲器、第一级差分放大电路和第二级差分放大 电路; 数据采样通道具有模数转换电路; 数据处理和时序控制电路是具有数据运算能力、 数据输出输入接口的中央处理器 (CPU、 MCU),中央处理器具有控制软件、数据处理软件。 图 25所示是一种瞬时值测量法的触控信号检测电路结构图, 2510是触控信号采样点 的信号,2511是检测参考点的信号,触控信号采样点的信号 2510和检测参考点的信号 2511 分别经过缓冲器 2520和缓冲器 2521缓冲后, 作为第一级差分放大器 2522的输入信号; 第一级差分放大器 2522的输出再作为第二级差分放大器 2523的其中一个输入, 2524是 调节电压输出, 其作为基准电位, 连接第二级差分放大器 2523的另一个输入, 用来减去 第一级差分放大电路输出信号的底值; 第二级差分放大器 2523输出到模数转换器 2525, 2525在中央处理器 (CPU、 MPU) 2526输出的同步控制信号 2530的控制下进行同步采 样, 采样的转换结果发送到中央处理器 (CPU、 MPU) 2526, 再由中央处理器进行数据 处理及触控判断。
图 26所示是一种瞬时值测量法的触控信号检测电路结构图, 2610是触控信号采样点 的信号,2611是检测参考点的信号,触控信号采样点的信号 2610和检测参考点的信号 2611 分别经过缓冲器 2620和缓冲器 2621缓冲后, 作为第一级差分放大器 2622的输入信号; 第一级差分放大器 2622的输出再作为第二级差分放大器 2623的其中一个输入,反馈调节 模拟电路 2624用第二级差分放大器 2623的输出作为反馈输入信号并自动调节输出电压, 其作为基准电位, 连接第二级差分放大器 2623的另一个输入, 用来减去第一级差分放大 电路输出信号的底值;第二级差分放大器 2623输出到模数转换器 2625, 2625在中央处理 器(CPU、 MPU) 2626输出的同步控制信号 2630的控制下进行同步采样, 采样的转换结 果发送到中央处理器 (CPU、 MPU) 2626, 再由中央处理器进行数据处理及触控判断。
图 27所示是一种瞬时值测量法的触控信号检测电路结构图, 2710是触控信号采样点 的信号,2711是检测参考点的信号,触控信号采样点的信号 2710和检测参考点的信号 2711 分别经过缓冲器 2720和缓冲器 2721缓冲后, 作为第一级差分放大器 2722的输入信号; 第一级差分放大器 2722的输出再作为第二级差分放大器 2723的其中一个输入,中央处理 器 (CPU、 MPU) 2726根据触控运算结果送出调节数据到数模转换器 2724, 2724的输 出电压作为基准电位, 连接第二级差分放大器 2723的另一个输入, 用来减去第一级差分 放大电路输出信号的底值;第二级差分放大器 2723输出到模数转换器 2725, 2725在中央 处理器(CPU、 MPU) 2726输出的同步控制信号 2730的控制下进行同步采样, 采样的转 换结果发送到中央处理器 (CPU、 MPU) 2726, 再由中央处理器进行数据处理及触控判 断。
图 25、 图 26、 图 27所示的三种瞬时值测量法触控信号检测电路的区别在于: 图 25 所示方案是手动的方法给二次差分电路设置一个基准电位,对二次差分电路具有基本的调 节能力; 图 26所示方案是二次差分电路的输出端信号经模拟电路再反馈给二次差分电路 作为基准电位, 对二次差分电路具有自动跟踪的调节能力; 图 27所示方案是将中央处理 器运算后的结果经数模转换电路反馈给二次差分电路作为基准电位,对二次差分电路具有 智能化的调节能力。
不同尺寸及分辨率的显示屏, 其电极的电阻一般在 2K以上, 检测电路与触控屏上电 极线的连接点上, 因检测电路的输入阻抗而对触控信号分流, 检测电路的输入阻抗越大, 对触控信号的分流作用越小。 当检测电路的输入阻抗为 2.5倍以上时, 触控信号都能反映 出触摸动作信息的,所以要求信号检测通道对电极线的输入阻抗在 5ΚΩ或 5ΚΩ以上,如 图 25、 26, 27在差分放大电路与触控屏上电极线的连接点之间加上缓冲器就是为了增大 检测电路的输入阻抗。
具体实施方式十七
具体实施方式十四和方式十五也可以使用平均值测量法,来对图 4的触控显示器 400 进行触控探测。这种平均值测量法是在一定的时间区段内进行对触控信号的检测,获得触 控信号的平均值作为测量结果。平均值测量法虽比瞬时值测量法慢,但其主要特点就是可 以消除部分高频干扰, 测量数据更平稳有利于触控的判断。有效值是平均值中的一种。实 现平均值测量法对触控信号检测的三种电路结构如图 28、 图 29和图 30所示。 其触控信 号检测电路结构都是由信号检测通道、数据采样通道、数据处理和时序控制电路组成。信 号检测通道具有缓冲器、 第一级差分放大电路、 有效值测量电路和第二级差分放大电路; 数据采样通道具有模数转换电路;数据处理和时序控制电路是具有数据运算能力、数据输 出输入接口的中央处理器 (CPU、 MCU), 中央处理器具有控制软件、 数据处理软件。
图 28所示是一种平均值测量法的触控信号检测电路结构图, 2810是触控信号采样点 的信号,2811是检测参考点的信号,触控信号采样点的信号 2810和检测参考点的信号 2811 分别经过缓冲器 2820和缓冲器 2821缓冲后, 作为第一级差分差分放大电路单元 2822的 输入信号; 第一级差分差分放大电路单元 2822内含频率选通电路, 选通电路的选通频率 为激励源触控信号的频率,其对差分放大的输出进行选通,选通后的输出再作为有效值转 换器 2823的输入, 2823的有效值输出作为第二级差分放大器 2824的输入; 2825是调节 电压输出, 其作为基准电位, 连接到第二级差分放大器 2824的另一个输入端, 用来减去 2823 的有效值输出信号的底值; 第二级差分放大器 2824输出到模数转换器 2826, 2826 在中央处理器(CPU、 MPU) 2827输出的同步控制信号 2830的控制下进行同步采样, 采 样的转换结果发送到中央处理器 (CPU、 MPU) 2827, 再由中央处理器进行数据处理及 触控判断。
图 29所示是一种平均值测量法的触控信号检测电路结构图, 2910是触控信号采样点 的信号,2911是检测参考点的信号,触控信号采样点的信号 2910和检测参考点的信号 2911 分别经过缓冲器 2920和缓冲器 2921缓冲后, 作为第一级差分差分放大电路单元 2922的 输入信号; 第一级差分差分放大电路单元 2922内含频率选通电路, 选通电路的选通频率 为激励源触控信号的频率,其对差分放大的输出进行选通,选通后的输出再作为有效值转 换器 2923的输入, 2923的有效值输出作为第二级差分放大器 2924的输入; 反馈调节模 拟电路 2925用第二级差分放大器 2924的输出作为反馈输入信号并自动调节输出电压,其 作为基准电位,连接到第二级差分放大器 2924的另一个输入端,用来减去 2923的有效值 输出信号的底值; 第二级差分放大器 2924输出到模数转换器 2926, 2926在中央处理器
( CPU、 MPU) 2927输出的同步控制信号 2930的控制下进行同步采样, 采样的转换结果 发送到中央处理器 (CPU、 MPU) 2927, 再由中央处理器进行数据处理及触控判断。
图 30所示是一种平均值测量法的触控信号检测电路结构图, 3010是触控信号采样点 的信号,3011是检测参考点的信号,触控信号采样点的信号 3010和检测参考点的信号 3011 分别经过缓冲器 3020和缓冲器 3021缓冲后, 作为第一级差分差分放大电路单元 3022的 输入信号; 第一级差分差分放大电路单元 3022内含频率选通电路, 选通电路的选通频率 为激励源触控信号的频率,其对差分放大的输出进行选通,选通后的输出再作为有效值转 换器 3023的输入, 3023的有效值输出作为第二级差分放大器 3024的输入; 中央处理器
( CPU、 MPU) 3027根据触控运算结果送出调节数据到数模转换器 3025, 3025的输出 电压作为基准电位,连接到第二级差分放大器 3024的另一个输入端,用来减去 3023的有 效值输出信号的底值;第二级差分放大器 3024输出到模数转换器 3026, 3026在中央处理 器(CPU、 MPU) 3027输出的同步控制信号 3030的控制下进行同步采样, 采样的转换结 果发送到中央处理器 (CPU、 MPU) 3027, 再由中央处理器进行数据处理及触控判断。
图 28、 图 29和图 30所示的三种平均值测量法触控信号检测电路的区别在于: 图 28 所示方案是手动的方法给二次差分电路设置一个基准电位,对二次差分电路具有基本的调 节能力; 图 29所示方案是二次差分电路的输出端信号经模拟电路再反馈给二次差分电路 作为基准电位, 对二次差分电路具有自动跟踪的调节能力; 图 30所示方案是将中央处理 器运算后的结果经数模转换电路反馈给二次差分电路作为基准电位,对二次差分电路具有 智能化的调节能力。
不同尺寸及分辨率的显示屏, 其电极的电阻一般在 2K以上, 检测电路与触控屏上电 极线的连接点上, 因检测电路的输入阻抗而对触控信号分流, 检测电路的输入阻抗越大, 对触控信号的分流作用越小。 当检测电路的输入阻抗为 2.5倍以上时, 触控信号都能反映 出触摸动作信息的,所以要求信号检测通道对电极线的输入阻抗在 5ΚΩ或 5ΚΩ以上,如 图 28、 29, 30在差分放大电路与触控屏上电极线的连接点之间加上缓冲器就是为了增大 检测电路的输入阻抗。
具体实施方式十八 在介绍实施例十四时我们提到, 图 4所示的触控显示器 400, 显示器采用 TFT-LCD, 测量的等效电路如图 18所示。触控激励源 1810为方波信号, 由于 1830和 1831是电容负 载, 触控激励的方波信号在这两个电容上出现充放电波形。 触控激励源 1810的输出波形 和触控信号采样点 1841 的触控信号波形如图 21所示, 为了说明本实施例, 现重新对图 21标号, 如图 31所示。
本实施方式对触控信号的检测方法采用时间特征测量法, 测量触控信号采样点 1841 充放电过程中两个既定电位间的时间间隔的变化, 来获取触控信息。 如图 31所不, 测量 触控信号采样点 1841波形的充电过程中两个既定电位 V422和 V421之间的时间 Τ423 , 放电过程中两个既定电位 V421和 V422之间的时间 Τ424,可以反映这个电容负载的变化。 当手指触摸显示屏时图 18等效电路的耦合电容 1831就会产生,改变了电路的电容负载以 及时间常数, 两个既定电位间的时间间隔 Τ423和 Τ424也就发生了改变。 测量时间间隔 Τ423和 Τ424的变化就可以获得触控的信息, 既定电位 V421和 V422选取充放电过程中 采样点 1841的两个电位。
实现时间特征测量法触控信号检测的电路结构如图 32和图 33所示。其触控信号检测 电路结构都是由信号检测及数据采样通道、数据处理和时序控制电路组成。信号检测及数 据采样通道具有缓冲器、数模转换电路或电压调节输出单元、 比较器、 记数器; 数据处理 和时序控制电路是具有数据运算能力、数据输出输入接口的中央处理器 (CPU、 MCU), 中 央处理器具有控制软件、 数据处理软件。
图 32是一种时间特征测量法的触控信号检测电路结构图, 3210是触控信号采样点的 信号, 3211是一个既定电位 (V421 ), 由电压调节输出单元 3220来产生, 3212是一个既 定电位(V422), 由电压调节输出单元 3221来产生; 触控信号采样点的信号 3210经过缓 冲器 3230缓冲输出, 与 3211这个既定电位进入比较器 3232进行比较; 触控信号采样点 的信号 3210经过缓冲器 3231缓冲输出,与 3212这个既定电位进入比较器 3233进行比较; 中央处理器 (CPU、 MCU)3235产生计数器 3234的记数脉冲信号 3240, 比较器 3233的输 出电位作为计数器 3234的启动记数信号, 比较器 3232的输出电位作为计数器 3234的停 止记数信号; 计数器 3234停止记数后的读数由中央处理器 (CPU、 MCU)3235读取, 读数 完毕后由中央处理器 (CPU、 MCU)3235送出清零信号 3241清零计数器 3234, 为下一次读 数做好准备, 并由中央中央处理器 (CPU、 MCU)3235进行数据处理及触控判断。
图 33是一种时间特征测量法的触控信号检测电路结构图, 3310是触控信号采样点的 信号, 中央处理器 (CPU、 MCU)3327 通过程序预置或历史检测判断而输出相应数据到数 模转换器 3320输出一个既定电位 3311 (V421 ) , 也输出数据到数模转换器 3321输出一个 既定电位 3312 (V422);触控信号采样点的信号 3310经过缓冲器 3322缓冲输出, 与 3311 这个既定电位进入比较器 3324;触控信号采样点的信号 3310经过缓冲器 3323缓冲输出, 与 3312这个既定电位进入比较器 3325 ; 中央处理器 (; CPU、 MCU)3327产生计数器 3326 的记数脉冲信号 3330, 比较器 3325的输出电位作为计数器 3326的启动记数信号, 比较 器 3324的输出电位作为计数器 3326的停止记数信号; 计数器 3326停止记数后的读数由 中央处理器 (CPU、 MCU)3327读取, 读数完毕后由中央处理器 (CPU、 MCU)3327送出清 零信号 3331 清零计数器 3326, 为下一次读数做好准备, 并由中央中央处理器 (CPU、 MCU)3327进行数据处理及触控判断。
图 32和图 33所示的两种时间特征测量法触控信号检测的区别在于: 图 32所示方案 是手动的方法给比较器设置两个既定电位 V421和 V422; 图 33所示方案是由中央处理器 给比较器设置两个既定电位 V421和 V422, 中央处理器通过程序预置或将之前的测量结 果运算后输出对应数据到数模转换电路, 使其输出作为既定比较电位, 对既定比较电位 V421和 V422的设置具有智能化的调节能力。
具体实施方式十九
与实施例十八不同, 本例中触控激励源 1810为正弦波信号, 由于 1830和 1831是电 容负载, 正弦波的触控激励源带上电容负载后, 在触控信号采样点上的波形还是正弦波, 但发生了幅度和相位的变化,触控激励源 1810的输出波形和触控信号采样点 1841的触控 信号波形如图 23所示。
本实施方式对触控信号的检测方法采用相移测量法,比较不同的帧消隐时间段上触控 信号采样点 1841上特定相位点的相位移动, 来获取触控信息。 可以看出可以通过测量相 位的改变来反映这个触摸电容的影响,而相位的改变也可以从测量时间间隔来反映,这个 时间间隔的检测示意图亦见如图 23所示,显示屏无手指触摸时, 由于图 18中的分布电容 1830的存在, 检测触控信号采样点 1841上的触控信号波形相对触控激励源输出端 1840 的波形有相位的延迟;当手指触摸显示屏时图 18所示等效电路的耦合电容 1831就会产生, 增大了电路的电容负载, 触控信号采样点 1841上的过零点与激励源之间的过零点之间的 时间 T500会变大, 即产生进一歩的相移。 测量时间 T500的变化就可获得触控的信息。 根据触控激励源波形的不同, 特定相位点对应的电位可以是零点或者是其它电位点。
实现相移测量法触控信号检测的电路结构如图 34和图 35所示。其触控信号检测电路 结构都是由信号检测及数据采样通道、数据处理和时序控制电路组成。信号检测及数据采 样通道具有缓冲器、数模转换电路或电压调节输出单元、 比较器、 记数器; 数据处理和时 序控制电路是具有数据运算能力、数据输出输入接口的中央处理器 (CPU、 MCU), 中央处 理器具有控制软件、 数据处理软件。
图 34是一种相移特征测量法的触控信号检测电路结构图, 3410是触控信号采样点的 信号, 3411是检测参考点的信号, 3412是由电压调节输出单元 3420产生的对应一个特定 相位点时的电位; 触控信号采样点的信号 3410经过缓冲器 3430缓冲输出, 与 3412这个 特定相位点对应的电位进入比较器 3432进行比较;触控信号采样点的信号 3411经过缓冲 器 3431缓冲输出, 与 3412这个特定相位点对应的电位进入比较器 3433进行比较; 中央 处理器 (CPU、 MCU)3435产生计数器 3434的记数脉冲信号 3440, 比较器 3433的输出电 位作为计数器 3434的启动记数信号, 比较器 3432的输出电位作为计数器 3434的停止记 数信号; 计数器 3434记数停止后的读数由中央处理器 (CPU、 MCU)3435读取, 读数完毕 后由中央处理器 (CPU、 MCU)3435送出清零信号 3441清零计数器 3434, 为下一次读数做 好准备, 并由中央中央处理器 (CPU、 MCU)3435进行数据处理及触控判断。
图 35是一种相移特征测量法的触控信号检测电路结构图, 3510是触控信号采样点的 信号, 3511是检测参考点的信号, 中央处理器 (CPU、 MCU)3526根据程序预设或者历史 检测判断而输出相应数据到数模转换器 3520,特定相位点对应的电位 3512即是数模转换 器 3520的输出电位; 触控信号采样点的信号 3510经过缓冲器 3521缓冲输出, 与 3512 这个特定相位点对应的电位进入比较器 3523进行比较;触控信号采样点的信号 3511经过 缓冲器 3522缓冲输出, 与 3512这个特定相位点对应的电位进入比较器 3524进行比较; 中央处理器 (CPU、 MCU)3526产生计数器 3525的记数脉冲信号 3530, 比较器 3524的输 出电位作为计数器 3525的启动记数信号, 比较器 3523的输出电位作为计数器 3525的停 止记数信号; 计数器 3525记数停止后的读数由中央处理器 (CPU、 MCU)3526读取, 读数 完毕后由中央处理器 (CPU、 MCU)3526送出清零信号 3531清零计数器 3525, 为下一次读 数做好准备, 并由中央中央处理器 (CPU、 MCU)3526进行数据处理及触控判断。
图 34和图 35所示的两种相移测量法触控信号检测的区别在于: 图 34所示方案是用 手动的方法设定特定相位点对应的电位; 图 35所示方案是由中央处理器通过数模转换器 来设定特定相位点对应的电位,中央处理器通过程序预设或将之前的测量结果运算后经数 模转换器反馈作为特定相位点对应的电位, 对特定相位点的设置具有智能化的调节能力。
本实施方式所测量的触控信号相位特征实质上也是时间特征的一种。
具体实施方式二十
图 4所示的触控显示器 400, 时分复用显示屏电极来完成触控功能。 触控显示器 400 以部分的或全部的 N条显示屏电极线时分复用作触控感应电极线, 以单通道顺序扫描的 检测方式进行触控探测:触控信号检测电路具有一个触控信号检测通道或一个数据采样通 道, 以扫描的方式依次顺序检测 N条触控感应电极线中的第一条、 第二条、 ...、 直至最 后的第 N条触控感应电极线, 从而完成一个探测帧的全部检测过程, 如图 36所示。
这也是最常规和自然的触控检测方式。 具体实施方式二 ^一
与实施例二十不冋,本例中是按某一既定的间隔 i以扫描的方式检测 N条触控感应电 极中的第一条电极、 第 i+1条、 第 2i+l条、 ...、 直至到最后的第 N条触控感应电极线, 从而完成一个探测帧的全部检测过程。
i=2时, 即间隔一条触控感应电极线的检测扫描示意图如图 37所示。
具体实施方式二十二
与实施例二十一和二十二不同的是,本例是以单通道粗扫加细扫的检测方式进行触控 探测:触控信号检测电路具有一个检测通道或一个数据采样通道,把触控感应电极线按每 i条一区划分为几个分区, 每个分区选取一条或多条触控感应电极线作为该分区触控感应 电极线的触控感应代表电极一起进行触控检测,最好的方法是把每个分区里面全部的触控 感应电极线并联作为一条触控感应代表电极;先按区对触控感应代表电极进行检测,确定 触控动作发生的区域;再在有触控动作发生的区域里面进行细分扫描检测,获得更具体的 触控信息。 此方法的目的是为了节省触控检测的时间。
i=3时, 单通道粗扫加细扫的检测扫描示意图如图 38所示。
具体实施方式二十三
本例以多通道顺序扫描的检测方式进行触控探测:触控信号检测电路具有多个触控信 号检测通道和多个数据采样通道,把全部的触控感应电极线分为跟触控信号检测通道数目 相同的组数, 每一个触控信号检测通道负责一个触控感应电极组内的检测。
一种方案是各触控信号检测通道同时分别在各自组内进行顺序扫描检测,综合全部触 控信号检测通道的检测结果, 获得全屏幕的触控信息。 图 39是三个触控信号检测通道时 的扫描顺序示意图。
另一种方案是各触控信号检测通道同时分别在各自组内进行间隔扫描检测,综合全部 触控信号检测通道的检测结果, 获得全屏幕的触控信息。 图 40是三个触控信号检测通道 时的扫描顺序示意图。
再一种方案是各触控信号检测通道同时分别在各自组内进行粗扫加细扫检测, 综合 全部触控信号检测通道的检测结果, 获得全屏幕的触控信息。 图 41是三个触控信号检测 通道时的扫描顺序示意图。
以上内容是结合具体的优选实施方式对本发明所作的进一步详细说明,不能认定本发 明的具体实施只局限于这些说明。对于本发明所属技术领域的普通技术人员来说,在不脱 离本发明构思的前提下,还可以做出若干简单推演或替换,都应当视为属于本发明的保护 范围。

Claims

权 利 要 求 书
1、 一种可排除显示影响触控的触控显示器, 包括有源液晶显示屏、 显示驱动电路、 触控电路, 以及使显示屏电极既用于显示驱动又用于触控探测的显示 /触控信号选通输出 电路或显示 /触控信号加载电路; 所述触控电路具有触控激励源和触控信号检测电路; 所 述显示 /触控信号选通输出电路使显示屏电极或与显示驱动电路连通传输显示驱动信号, 或与触控探测电路连通传输触控信号,显示驱动和触控探测时分复用显示屏电极;所述显 示 /触控信号加载电路使显示屏电极同时传输显示驱动信号和触控信号, 显示驱动和触控 探测同时共用显示屏电极;在有源液晶显示屏的至少一片基板上具有有源器件阵列和连接 有源器件阵列的行电极组、列电极组, 在显示屏的另一片基板上具有公共电极, 其特征在 于:
正常显示时段结束后,在显示屏部分或全部行列电极线上和公共电极上施加液晶预驱 动信号,液晶预驱动信号的大小是要让施加有液晶预驱动信号的行列电极线相对公共电极 之间所具有的电位差不小于液晶的饱和驱动电压,使施加有液晶预驱动信号的行列电极线 与公共电极之间的液晶分子处于确定的排列状态,排除显示内容变化对触控信号检测的影 响。
2、 根据权利要求 1所述的触控显示器, 其特征在于:
所述在显示屏部分或全部行列电极线上和公共电极上所施加的液晶预驱动信号,是同 时或不同时施加在不同的行列电极线上; 在行列电极线上施加有液晶预驱动信号的时段 内, 在公共电极上也有施加液晶预驱动信号的时刻。
3、 根据权利要求 1所述的触控显示器, 其特征在于:
所述在显示屏部分或全部行列电极线上和公共电极上所施加的液晶预驱动信号,是在 对显示屏部分或全部行列电极线上和公共电极上施加液晶预驱动信号后,再对施加过液晶 预驱动信号的行列电极线施加触控信号, 并检测电极线上触控信号的变化。
4、 根据权利要求 1所述的触控显示器, 其特征在于:
所述在显示屏部分或全部行列电极线上和公共电极上所施加的液晶预驱动信号,是在 对行列电极线施加触控信号的同时,或在对行列电极线施加触控信号之后,对显示屏部分 或全部行列电极线上和公共电极上施加液晶预驱动信号;在施加液晶预驱动信号后,再检 测施加过液晶预驱动信号的电极线上触控信号的变化。
5、 根据权利要求 1所述的触控显示器, 其特征在于:
所述显示屏上的有源器件阵列是 TFT阵列,行列电极线分别连接 TFT的栅极和源极、 或分别连接 TFT的栅极和漏极, 对连接 TFT源极或漏极的列电极线具有同时施加液晶预 驱动信号的时段。
6、 根据权利要求 1所述的触控显示器, 其特征在于:
所述对显示屏部分或全部行列电极线上和公共电极上施加液晶预驱动信号,是在显示 屏上全部的或部分的与显示象素相连的有源器件处于截止状态的时段。
7、 根据权利要求 1所述的触控显示器, 其特征在于:
所述液晶预驱动信号是在显示屏上与显示象素相连的有源器件的导通状态时段施加。
8、 根据权利要求 1所述的触控显示器, 其特征在于:
所述液晶预驱动信号和触控信号是在显示屏上与显示象素相连的有源器件的导通状 态时段同时施加。
9、 根据权利要求 7或 8所述的触控显示器, 其特征在于:
所述显示屏上的有源器件阵列是 TFT阵列, 在与显示象素相连的 TFT的导通状态时 段, 对连接 TFT源极或漏极的列电极线和公共电极施加液晶预驱动信号。
10、 根据权利要求 1或 7或 8所述的触控显示器, 其特征在于:
所述在行或列电极组上或公共电极上施加的液晶预驱动信号,是交流信号、直流信号、 交流和直流混合信号中的一种。
11、 根据权利要求 1或 7或 8所述的触控显示器, 其特征在于:
所述施加在显示屏同一电极上的液晶预驱动信号和触控信号是频率或波形相同的交 流信号。
12、 根据权利要求 1或 7或 8所述的触控显示器, 其特征在于:
所述液晶预驱动信号的频率是 10kHz或 ΙΟΚΗζ以上。
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