WO2014048009A1 - 一种触摸屏的esd保护装置 - Google Patents

一种触摸屏的esd保护装置 Download PDF

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Publication number
WO2014048009A1
WO2014048009A1 PCT/CN2012/084206 CN2012084206W WO2014048009A1 WO 2014048009 A1 WO2014048009 A1 WO 2014048009A1 CN 2012084206 W CN2012084206 W CN 2012084206W WO 2014048009 A1 WO2014048009 A1 WO 2014048009A1
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Prior art keywords
esd protection
touch screen
esd
protection circuit
thin film
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PCT/CN2012/084206
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English (en)
French (fr)
Inventor
黄忠守
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上海天马微电子有限公司
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Application filed by 上海天马微电子有限公司 filed Critical 上海天马微电子有限公司
Priority to EP12879147.2A priority Critical patent/EP2902885B1/en
Priority to US14/096,302 priority patent/US9520715B2/en
Publication of WO2014048009A1 publication Critical patent/WO2014048009A1/zh

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    • 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
    • GPHYSICS
    • G02OPTICS
    • G02FOPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333Constructional arrangements; Manufacturing methods
    • G02F1/13338Input devices, e.g. touch panels
    • GPHYSICS
    • G02OPTICS
    • G02FOPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2202/00Materials and properties
    • G02F2202/22Antistatic materials or arrangements

Definitions

  • the present invention relates to the field of touch screen technologies, and in particular, to an ESD protection device for a touch screen. Background technique
  • TFT Thin film transistor
  • A-LCDs active matrix type liquid crystal displays
  • TFT-LCD is the only display device that fully catches up with and exceeds CRT in terms of brightness, contrast, power consumption, life, volume and weight. It has excellent performance, large-scale production characteristics, high degree of automation, and raw material cost. Low cost, therefore, the application is more and more extensive.
  • the TFT-LCD touch screen is a two-dimensional image signal output device, which is the same as the image collection device.
  • the touch screen with a charge integrating amplifier is a two-dimensional touch signal output device, and the sensing line needs to collect relatively small external signals. Therefore, it is important to contain various dark backgrounds including static and dynamic dark currents from the sense lines on the touch screen.
  • the capacitance of the touch electrode is large, a small amount of static electricity does not cause breakdown of the insulating film, so the current capacitive touch screen has not been provided with an ESD protection circuit.
  • the resolution of the touch electrodes is greatly increased, the capacitance of each electrode becomes smaller.
  • the probability of electrostatic breakdown generally increases with the increase of the touch screen substrate. Therefore, it is necessary to add an ESD protection circuit dedicated to the touch screen on the TFT-LCD panel, and then connect the ESD protection circuit to the sensing or driving electrode of the touch screen through the upper and lower electrical connection.
  • the ESD protection circuit used in the most commonly used TFT-LCDs, as shown in Figure 1, is used to protect the data lines and scan lines of the TFT-LCD from being broken down by static electricity.
  • the ESD circuit can also easily conceive driving signals for the touch screen and sensing signal electrodes from being broken down by static electricity.
  • the ESD protection circuit shown in Fig. 1 is composed of two TFTs (T1 and T2) back to back, which are connected between the ground line 12 and the sensing line or driving line 11.
  • this figure is a graph of the static leakage current and the voltage across the ESD protection circuit in Figure 1.
  • the ESD protection circuit shown in Figure 1 can quickly leak static electricity accumulated on the glass substrate and static electricity transmitted from the machine and the environment during the manufacturing process of the product, thereby protecting the TFT-LCD touch screen itself.
  • the static leakage of the ESD protection circuit The flow is likely to saturate or paralyze the touch screen's preamplifier, such as a charge integrating amplifier. Therefore, those skilled in the art need to address the effect of static leakage current of the ESD protection circuit on the TFT-LCD touch screen.
  • the technical problem to be solved by the present invention is to provide an ESD protection device for a touch screen, which can effectively solve the influence of static leakage current of the ESD protection circuit on the TFT-LCD touch screen.
  • the invention provides an ESD protection device for a touch screen, comprising:
  • the protection switch When the electrostatic potential of the sensing line or the driving line of the touch screen is greater than or equal to a preset potential, the protection switch is turned on, and the ESD protection circuit and the protection switch form a path for leaking static electricity of the sensing line or the driving line to the periphery.
  • the protection switch is connected between the ESD protection circuit and the sensing line of the touch screen; or the protection switch is connected between the ESD protection circuit and the driving line of the touch screen; or the protection switch is connected to the ESD protection Between the circuit and the ESD discharge bus; or the protection switch is connected between the ESD protection circuit and the ground bus; or
  • the protection switch is connected between the ESD protection circuit and the common electrode bus.
  • the ESD protection circuit includes at least one protection switch.
  • the protection switch is a third thin film transistor TFT, and the third TFT is connected between the ESD protection circuit and the sensing line of the touch screen, and the control gate of the third TFT passes another ESD.
  • the protection circuit or resistive device is connected to the ground bus, or the common electrode bus, or the ESD discharge bus.
  • the protection switch comprises a fourth thin film transistor and a fifth thin film transistor connected in series, the control gates of the fourth thin film transistor and the fifth thin film transistor being controlled by two control pulses which are mutually inverted;
  • the fourth thin film transistor and the fifth thin film transistor are both PMOS transistors or both.
  • the protection switch comprises two TFTs connected in series, one TFT is an NMOS transistor, and the other TFT is a PMOS transistor, and the gates of the NMOS transistor and the PMOS transistor are the same A control pulse control.
  • the protection switch is a low-temperature polysilicon LTPS, a cadmium selenide CdSe or an oxide semiconductor double-gate TFT, and the top gate and the bottom gate of the double-gate TFT are respectively inverted by two Control pulse control.
  • the ESD protection circuit includes at least one pair of thin film transistors including a first thin film transistor and a second thin film transistor connected in a back-to-back manner.
  • the plurality of pairs of thin film transistors of the ESD protection circuit may be connected in series, in parallel or in series and in parallel.
  • the ESD protection circuit is fabricated on the same substrate as the protection switch and the TFT array of the display.
  • the ESD protection device is applied to a two-dimensional spatial image imaging device
  • the TFT array is used to drive a liquid crystal display or an organic light emitting diode array.
  • the present invention has the following advantages:
  • the ESD protection device of the touch screen comprises: an ESD protection circuit and a protection switch connected in series with the ESD protection circuit; when the electrostatic potential of the sensing line or the driving line of the touch screen is greater than or equal to a preset potential during the manufacturing process, the protection The switch is turned on, and the ESD protection circuit and the protection switch form a path for leaking static electricity of the sensing line or the driving line to the peripheral common electrode bus, or the ESD discharging bus, or the grounding bus; thereby protecting the driving signal of the touch screen And the sensing signal electrode is protected from electrostatic breakdown.
  • the protection switch is turned off, thereby greatly reducing the static leakage current that affects the touch screen. The effect of the static leakage current of the ESD protection circuit on the TFT-LCD touch screen can be effectively solved.
  • FIG. 1 is a schematic diagram of an ESD protection circuit in the prior art
  • FIG. 2 is a graph of static leakage current and voltage at both ends of the ESD protection circuit of FIG. 1;
  • FIG. 3 is a schematic diagram of a first embodiment of an ESD protection device for a touch screen provided by the present invention.
  • FIG. 4 is another schematic diagram of Embodiment 1 of an ESD protection device for a touch screen provided by the present invention
  • 5 is a schematic diagram of Embodiment 2 of an ESD protection device for a touch screen provided by the present invention
  • FIG. 6 is another schematic diagram of Embodiment 2 of an ESD protection device for a touch screen provided by the present invention
  • FIG. 7 is a touch screen ESD protection device provided by the present invention.
  • Example 3
  • FIG. 8 is a schematic diagram of a touch screen ESD protection device according to a fourth embodiment of the present invention
  • FIG. 9 is a schematic diagram of a fifth embodiment of an ESD protection device for a touch screen provided by the present invention.
  • FIG. 3 the figure is a schematic diagram of Embodiment 1 of an ESD protection device for a touch screen provided by the present invention.
  • the ESD protection device provided by the embodiment of the invention includes: an ESD protection circuit and a protection switch connected in series with the ESD protection circuit;
  • the ESD protection circuit provided in this embodiment is implemented by a pair of back-to-back TFTs. As shown in FIG. 3, the ESD protection circuit includes two back-to-back TFTs, which are a first thin film transistor T1 and a second thin film transistor T2, respectively. It can be understood that the ESD protection circuit can also be implemented in other connections by other tubes. For example, the ESD protection circuit includes a plurality of TFTs connected in series, in parallel, or in series and in parallel.
  • connection of a pair of TFTs shown in Figure 3 is as follows:
  • the back-to-back mode connection means that the gate G and the source S of T1 are connected to the drain D of T2, and the drain D of T1 is connected to the gate G and the source S of T2.
  • connection mode of the above thin film transistor is an embodiment, and depending on the type of the thin film transistor, a plurality of connection modes are also possible.
  • the protection switch T3 When the electrostatic potential of the sensing line or the driving line of the touch screen is greater than or equal to a preset potential, the protection switch T3 is turned on, and the ESD protection circuits T1 and T2 and the protection switch T3 form a path for sensing lines or driving lines.
  • the static electricity of 11 leaks to the peripheral common electrode bus, or the ESD discharge bus, or the ground bus 12; thereby protecting the driving signal of the touch screen and the sensing signal electrode from electrostatic breakdown.
  • the protection switch T3 When the panel of the touch screen is normally driven, the protection switch T3 is turned off.
  • the protection switch T3 device is in an off state to isolate the common electrode bus bar around the touch screen, or the ESD discharge bus bar, or the ground bus bar 12, to prevent the sensing signal of the touch screen from leaking to an external detecting circuit connected to the sensing line. For example, the leakage current of the preamplifier of the touch screen is prevented from leaking to the peripheral circuit.
  • the same mechanism is also applied to the ESD protection devices T1 and T2 and the protection switch T3 connected to the drive line.
  • the switching device When the touch screen is normally driven, the switching device is in an off state in order to prevent the driving signal from leaking through the driving line 11 to the common electrode bus bar around the touch screen, or the ESD discharging bus bar or the ground bus bar 12 to increase the driving. Power consumption. At the same time, this can also greatly reduce the static leakage current that affects the touch screen. The effect of static leakage current of the ESD protection circuit on the TFT-LCD touch screen can be effectively solved.
  • the protection switch in this embodiment is described by taking a TFT as an example, as shown in Figure 3.
  • the turn-on and turn-off of ⁇ 3 is controlled by a control pulse applied to its control gate.
  • the protection switch only needs to be connected in series with the ESD protection circuit.
  • the specific serial position may have the following types:
  • the protection switch ⁇ 3 is connected between the ESD protection circuit and the sensing line of the touch screen; or the protection switch ⁇ 3 is connected between the ESD protection circuit and the driving line of the touch screen; or the protection switch ⁇ 3 is connected Between the ESD protection circuit and the ESD discharge bus; or the protection switch ⁇ 3 is connected between the ESD protection circuit and the ground line; or
  • the protection switch ⁇ 3 is connected between the ESD protection circuit and the common electrode line.
  • the protection switch ⁇ 3 in the embodiment shown in Fig. 3 is connected between the ESD protection circuit (consisting of two back-to-back T1 and ⁇ 2) and the ground line 12, and the ⁇ 3 in the embodiment shown in Fig. 4 is connected to the ESD protection circuit. (composed of two back-to-back T1 and ⁇ 2) and the sensing line or drive line 11.
  • the figure is a schematic diagram of Embodiment 2 of an ESD protection device for a touch screen provided by the present invention.
  • the protection switch is a third thin film transistor ⁇ 3, and the ⁇ 3 is connected between the ESD protection circuit (composed of two back-to-back T1 and ⁇ 2) and the sensing line 11 of the touch screen, or
  • the control gate of the ⁇ 3 is connected to the control pulse while the control gate of the ⁇ 3 passes
  • Another ESD protection circuit (consisting of two back-to-back ⁇ 7 and ⁇ 8 in FIG. 5) or a resistive device (not shown) is connected to the ground bus, or the common electrode bus, or the ESD discharge bus 12.
  • the embodiment provided in Figure 5 is primarily for the control gate of the TFT to be no floating state during the manufacturing process.
  • the ESD protection circuit composed of the back-to-back TFT leaks to the common electrode bus, or the ESD discharge bus, or the ground bus.
  • the TFT of the protection switch T3 is in an off state.
  • the protection switch T3 can also be connected to the ESD protection circuit (composed of two back-to-back T1 and T2) and the ground bus, or the common electrode bus, or the ESD discharge bus 12 And connected to the ground bus, or the common electrode bus, or the ESD discharge bus 12 by another ESD protection circuit (composed of two back-to-back T7 and T8) or a resistive device (not shown).
  • FIG. 7 is a schematic diagram of Embodiment 3 of an ESD protection device for a touch screen provided by the present invention.
  • the protection switch includes two TFT protection switches connected in series, as shown in FIG. 7 , T4 and T5, and the control gates of the two TFTs are mutually inverted.
  • the two control pulses are controlled. That is, T4 and T5 are alternately turned on, and when T4 is turned on, T5 is turned off; when T4 is turned off, T5 is turned on.
  • the purpose of setting the two protection switches T4 and T5 in this embodiment is to prevent the DC voltage on the control gate of the protection switch from causing the threshold voltage of the TFT to drift.
  • the other TFT protection switch T5 is turned off, so that the positive and negative pulses are alternately applied to the gates of the two TFT protection switches, which are movable in the gate insulating film of the TFT.
  • the drive of the ions is automatically offset or compensated. Therefore, the DC voltage of the control gate of the protection switch is not caused to drift the threshold voltage of the TFT.
  • the present invention also provides an embodiment.
  • FIG. 8 is a schematic diagram of Embodiment 4 of an ESD protection device for a touch screen provided by the present invention.
  • the touch screen ESD protection device provided in this embodiment is different from the third embodiment in that the protection switch may include two TFTs connected in series, one TFT is an NMOS transistor T4, and the other TFT is a PMOS transistor T5.
  • the gates of the NMOS transistor T4 and the PMOS transistor T5 are controlled by the same control pulse.
  • the conduction conditions of the NMOS transistor T4 and the PMOS transistor T5 are opposite, when the gates of the PMOS transistor T5 and the NMOS transistor T4 are controlled by the same control pulse, the PMOS transistor T5 and the NMOS transistor T4 are alternately turned on, and the PMOS transistor T5 is turned on.
  • the NMOS transistor T4 is turned off; when the NMOS transistor T4 is turned on, the PMOS transistor T5 is turned off.
  • FIG. 9 is a schematic diagram of Embodiment 5 of an ESD protection device for a touch screen provided by the present invention.
  • the protection switch is low temperature poly silicon (LTPS), cadmium selenide CdSe or an oxide semiconductor (eg, Indium Gallium Zinc Oxide)
  • LTPS low temperature poly silicon
  • CdSe cadmium selenide
  • oxide semiconductor eg, Indium Gallium Zinc Oxide
  • the double gate TFT, the top gate and the bottom gate of the double gate TFT are respectively controlled by two control pulses which are mutually inverted.
  • the top gate and the bottom gate can simultaneously control the underlying electron channel, and the external input inverting pulse controls the top gate and the bottom gate, cancel each other at the electron channel so that the double gate TFT is always turned off.
  • the protection switch and the TFT array of the display are simultaneously fabricated on one substrate.
  • the ESD protection device of the touch screen provided by the above embodiments of the present invention can be applied to a two-dimensional image receiver or a two-dimensional image collector.
  • a two-dimensional image receiver For example, on an X-ray image sensor, or on a two-dimensional touch screen.

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Abstract

本发明提供一种触摸屏的ESD保护装置,包括:ESD保护电路和与ESD保护电路串联的保护开关;当制造过程中触摸屏的感应线或驱动线的静电电位大于或等于预设电位时,所述保护开关导通,所述ESD保护电路和保护开关形成通路,用于将感应线或驱动线的静电泄露到周边的共电极母线,或ESD放电母线,或接地母线上去;从而可以保护触摸屏的驱动信号和感应信号电极免于被静电击穿。当所述触摸屏正常驱动时,所述保护开关断开,从而大大降低了影响触摸屏的静态的漏电流,可以有效解决静态漏电流对TFT-LCD触摸屏的影响。

Description

一种触摸屏的 ESD保护装置 技术领域
本发明涉及触摸屏技术领域, 特别涉及一种触摸屏的 ESD保护装置。 背景技术
薄膜晶体管 (TFT, Thin说 Film Transistor ) LCD是有源矩阵类型液晶显示 器 (AM-LCD)中的一种。 TFT-LCD是目前唯一在亮度、 对比度、 功耗、 寿命、 体积和重量等综合性能上全面赶上和超过 CRT的显示器件, 它的性能优良、 大规模生产特性好, 自动化程度高,原材料成本低廉, 因此,应用越来越广泛。
TFT-LCD触摸屏是二维的图像信号输出器件, 和图像釆集器件一样, 使 书
用电荷积分放大器的触摸屏是一个二维空间的触摸信号的输出器件,感应线上 需要釆集比较小的外来信号。 因此,遏制各种暗背景包括来自触摸屏上感应线 的静态和动态暗电流就变得非常重要。
由于触摸电极的电容较大, 少量电荷量的静电还不会引起绝缘膜的击穿, 所以目前使用的电容性触摸屏还没有设置 ESD保护电路。 然而当触摸电极的 解析度大幅提高后, 各个电极的电容便会变得更小。 在制造工艺中, 发生静电 破坏的几率通常会随着触摸屏基板的增大而越来越高。因此,需要在 TFT-LCD 面板上增设专用于触摸屏的 ESD保护电路, 然后将其通过上下电连接方式将 ESD 保护电路连接到触摸屏的感应或者驱动电极上去。 在现有的最普遍使用 的 TFT-LCD中使用的 ESD保护电路, 如图 1所示, 用来保护 TFT-LCD的数 据线和扫描线免于被静电所击穿。 该 ESD电路也可以容易地想到用于触摸屏 的驱动信号和感应信号电极免于被静电所击穿。
图 1所示的 ESD保护电路由背靠背的两个 TFT ( T1和 T2 )组成,该 ESD 保护电路连接在地线 12与感应线或驱动线 11之间。
如图 2所示, 该图为图 1中 ESD保护电路的静态漏电流和两端电压的曲 线图。
图 1所示的 ESD保护电路在产品的制造过程中可以迅速泄露掉玻璃基板 上积累的静电和从机器及环境传导过来的静电, 从而保护了 TFT-LCD触摸屏 本身。 但是在 TFT-LCD触摸屏的正常驱动过程中, ESD保护电路的静态漏电 流很可能使得触摸屏的前置放大器, 例如电荷积分放大器饱和或者麻痹。 因此, 本领域技术人员需要解决 ESD保护电路的静态漏电流对 TFT-LCD 触摸屏的影响。
发明内容
本发明要解决的技术问题是提供一种触摸屏的 ESD保护装置, 可以有效 解决 ESD保护电路的静态漏电流对 TFT-LCD触摸屏的影响。
本发明提供一种触摸屏的 ESD保护装置 , 包括:
ESD保护电路和与 ESD保护电路串联的保护开关;
当触摸屏的感应线或驱动线的静电电位大于或等于预设电位时,所述保护 开关导通, 所述 ESD保护电路和保护开关形成通路, 用于将感应线或驱动线 的静电泄露到周边的共电极母线, 或 ESD放电母线, 或接地母线上去;
当所述触摸屏的面板正常驱动时, 所述保护开关断开。
优选地 ,
所述保护开关连接在所述 ESD保护电路和触摸屏的感应线之间; 或 所述保护开关连接在所述 ESD保护电路和触摸屏的驱动线之间; 或 所述保护开关连接在所述 ESD保护电路和 ESD放电母线之间; 或 所述保护开关连接在所述 ESD保护电路和接地母线之间; 或
所述保护开关连接在所述 ESD保护电路和共电极母线之间。 优选地, 所 述 ESD保护电路至少包括一个保护开关。
优选地, 所述保护开关为一个第三薄膜晶体管 TFT, 当所述第三 TFT连 接在所述 ESD保护电路和触摸屏的感应线之间, 同时所述第三 TFT的控制栅 极通过另外一个 ESD保护电路或者电阻性器件连接到接地母线, 或者共电极 母线, 或者 ESD放电母线上。
优选地,所述保护开关包括串联在一起的第四薄膜晶体管和第五薄膜晶体 管,所述第四薄膜晶体管和第五薄膜晶体管的控制栅极被互为反相的两个控制 脉冲控制; 所述第四薄膜晶体管和第五薄膜晶体管均为 PMOS 管或者均为 丽 OS管。
优选地, 所述保护开关包括串联在一起的两个 TFT, 其中一个 TFT 为 NMOS管, 另一个 TFT为 PMOS管, 所述 NMOS管和 PMOS管的栅极用同 一个控制脉冲控制。
优选地, 所述保护开关为低温多晶硅 LTPS、 硒化镉 CdSe或者氧化物半 导体的双栅极 TFT, 所述双栅极 TFT中的顶栅极和底栅极分别被互为反相的 两个控制脉冲控制。
优选地, 所述 ESD保护电路包括至少一对薄膜晶体管, 所述一对薄膜晶 体管包括以背靠背方式连接的第一薄膜晶体管和第二薄膜晶体管。
优选地, 所述 ESD保护电路的多对薄膜晶体管可以以串连、 并联或串连 并联相结合的方式连接。
优选地, 所述 ESD保护电路与保护开关和显示器的 TFT阵列制作在同一 张基板上。
优选地, 该 ESD保护装置应用于二维的空间图像成像器件上;
或者探测二维空间的基于机械触摸和压力的传感器上;
或者基于声波、光波或者电磁波的直接或间接作用产生的二维空间信息的 传感器上。
优选地, 所述 TFT阵列用于驱动液晶显示器或者有机发光二极管阵列。 与现有技术相比, 本发明具有以下优点:
本发明提供的触摸屏的 ESD保护装置, 包括: ESD保护电路和与 ESD保 护电路串联的保护开关;当制造过程中触摸屏的感应线或驱动线的静电电位大 于或等于预设电位时, 所述保护开关导通, 所述 ESD保护电路和保护开关形 成通路, 用于将感应线或驱动线的静电泄露到周边的共电极母线, 或 ESD放 电母线, 或接地母线上去; 从而可以保护触摸屏的驱动信号和感应信号电极免 于被静电击穿。 当所述触摸屏正常驱动时, 所述保护开关断开, 从而大大降低 了影响触摸屏的静态的漏电流。 可以有效解决 ESD保护电路的静态漏电流对 TFT-LCD触摸屏的影响。
附图说明
图 1是现有技术中的 ESD保护电路示意图;
图 2是图 1中 ESD保护电路的静态漏电流和两端电压的曲线图; 图 3是本发明提供的触摸屏的 ESD保护装置实施例一示意图;
图 4是本发明提供的触摸屏的 ESD保护装置实施例一的另一示意图; 图 5是本发明提供的触摸屏的 ESD保护装置实施例二示意图; 图 6是本发明提供的触摸屏的 ESD保护装置实施例二的另一示意图; 图 7是本发明提供的触摸屏 ESD保护装置是实施例三示意图;
图 8是本发明提供的触摸屏 ESD保护装置是实施例四的示意图; 图 9是本发明提供的触摸屏的 ESD保护装置实施例五示意图。
具体实施方式
为使本发明的上述目的、 特征和优点能够更加明显易懂, 下面结合附图对 本发明的具体实施方式做详细的说明。
参见图 3 , 该图为本发明提供的触摸屏的 ESD保护装置实施例一示意图。 本发明实施例提供的 ESD保护装置, 包括: ESD保护电路和与 ESD保护 电路串联的保护开关;
需要说明的是, 本实施例中提供的 ESD保护电路以一对背靠背的 TFT来 实现。 如图 3所示, ESD保护电路包括两个背靠背的 TFT, 分别为第一薄膜 晶体管 T1和第二薄膜晶体管 T2。 可以理解的是, 该 ESD保护电路也可以以 其他管子以其他连接方式来实现。 例如, 所述 ESD保护电路包括多个以串联、 并联或串联并联相结合方式连接的一对 TFT。
图 3所示的一对 TFT的连接方式为:
所谓背靠背方式连接是指 T1的栅极 G及源极 S与 T2的漏极 D连接, T1 的漏极 D与 T2的栅极 G及源极 S连接。
需要说明的是, 上述薄膜晶体管的连接方式为一种实施例,根据薄膜晶体 管类型的不同, 还可以有多种连接方式。
当触摸屏的感应线或驱动线的静电电位大于或等于预设电位时,所述保护 开关 T3导通, 所述 ESD保护电路 T1和 T2和保护开关 T3形成通路, 用于将 感应线或驱动线 11的静电泄露到周边的共电极母线, 或 ESD放电母线, 或接 地母线 12上去; 从而可以保护触摸屏的驱动信号和感应信号电极免于被静电 击穿。
当所述触摸屏的面板正常驱动时, 所述保护开关 T3断开。 所述保护开关 T3器件处于断开状态以便隔绝触摸屏周边的共电极母线,或者 ESD放电母线, 或接地母线 12, 防止触摸屏的感应信号泄露到连接感应线的外部探测电路, 比如避免触摸屏的前置放大器的漏电流泄露到周边电路。对于连接到驱动线上 的所述 ESD保护器件 T1和 T2和保护开关 T3 , 也^ ^于同样的机制。 当所述 触摸屏在正常驱动时,所述开关器件处于断开的状态以便防止驱动信号通过驱 动线 11泄露到触摸屏周边的共电极母线,或者 ESD放电母线,或接地母线 12 上从而增大驱动的功耗。 同时, 这样也可以大大降低影响触摸屏的静态的漏电 流。 可以有效解决 ESD保护电路的静态漏电流对 TFT-LCD触摸屏的影响。
本实施例中的保护开关以 TFT为例进行介绍, 如图 3所示的 T3。 Τ3的导 通和断开通过加在其控制栅极的控制脉冲来控制。
需要说明的是,保护开关只要与 ESD保护电路串联即可,参考图 3和图 4 所示, 具体的串联位置可以有以下几种:
所述保护开关 Τ3连接在所述 ESD保护电路和触摸屏的感应线之间; 或 所述保护开关 Τ3连接在所述 ESD保护电路和触摸屏的驱动线之间; 或 所述保护开关 Τ3连接在所述 ESD保护电路和 ESD放电母线之间; 或 所述保护开关 Τ3连接在所述 ESD保护电路和接地线之间; 或
所述保护开关 Τ3连接在所述 ESD保护电路和共电极线之间。
图 3所示实施例中的保护开关 Τ3是连接在 ESD保护电路(由两个背靠背 的 T1和 Τ2组成 )和地线 12之间, 图 4所示实施例中的 Τ3是连接在 ESD保 护电路 (由两个背靠背的 T1和 Τ2组成 )和感应线或驱动线 11之间。
参见图 5, 该图为本发明提供的触摸屏的 ESD保护装置实施例二示意图。 需要说明的是, 所述保护开关为一个第三薄膜晶体管 Τ3 , 当所述 Τ3连接 在所述 ESD保护电路 (由两个背靠背的 T1和 Τ2组成)和触摸屏的感应线 11 之间, 或所述 Τ3连接在所述 ESD保护电路 (由两个背靠背的 T1和 Τ2组成) 和触摸屏的驱动线 11之间时, 所述 Τ3的控制栅极连接控制脉冲, 同时所述 Τ3的控制栅极通过另外一个 ESD保护电路(如图 5中由两个背靠背的 Τ7和 Τ8组成)或者电阻性器件(图中未示出)连接到接地母线, 或者共电极母线, 或者 ESD放电母线 12上。
图 5提供的实施例主要是为了在制造过程中, 该 TFT的控制栅极不再是 悬浮状态。 当感应线或者驱动线 11的静电位较高时, 会通过背靠背 TFT组成 的 ESD保护电路泄露到共电极母线, 或 ESD放电母线, 或接地母线上去。 而 在面板正常驱动时, 该保护开关 T3的 TFT则处于断开状态。
需要说明的是,如图 6所示的实施例中保护开关 T3也可以连接在 ESD保 护电路(由两个背靠背的 T1和 T2组成)和接地母线, 或者共电极母线, 或 者 ESD放电母线 12之间, 且通过另外一个 ESD保护电路(由两个背靠背的 T7和 T8组成)或者电阻性器件(图中未示出)连接到接地母线, 或者共电极 母线, 或者 ESD放电母线 12上。
参见图 7, 该图为本发明提供的触摸屏的 ESD保护装置实施例三示意图。 本实施例提供的触摸屏的 ESD保护装置中, 所述保护开关包括串联在一 起的两个 TFT保护开关, 如图 7所示的 T4和 T5, 该两个 TFT的控制栅极被 互为反相的两个控制脉冲控制。 即, T4和 T5交替导通, 当 T4导通时, T5断 开; 当 T4断开时, T5导通。
本实施例中保护开关 T4和 T5设置两个的目的是为了防止保护开关的控 制栅极上的直流电压导致 TFT的阔值电压发生漂移。 当一个 TFT保护开关 T4 导通时, 另一个 TFT保护开关 T5断开, 这样正极和负极的脉冲交替加在两个 TFT保护开关的栅极上, 它们对于 TFT的栅级绝缘膜中的可移动离子的驱动 就会得到自动抵消或者补偿。从而不会导致保护开关的控制栅极的直流电压使 TFT的阔值电压发生漂移。
为了解决 TFT保护开关的控制栅极的直流电压导致 TFT保护开关的阔值 电压发生漂移的问题, 本发明还提供了一种实施例。
参见图 8, 该图为本发明提供的触摸屏的 ESD保护装置实施例四示意图。 本实施例中提供的触摸屏 ESD保护装置与实施例三的不同之处在于, 所述保 护开关可以包括串联在一起的两个 TFT,其中一个 TFT为 NMOS管 T4, 另一 个 TFT为 PMOS管 T5 , 所述 NMOS管 T4和 PMOS管 T5的栅极用同一个控 制脉冲控制。 由于 NMOS管 T4和 PMOS管 T5的导通条件正好相反, 因此, 当 PMOS管 T5和 NMOS管 T4的栅极用同一个控制脉冲控制时, PMOS管 T5和 NMOS管 T4交替导通, PMOS管 T5导通时, NMOS管 T4截止; NMOS 管 T4导通时, PMOS管 T5截止。 这样, 当触摸屏正常工作时, 来自 GND或 者短路棒的漏电流便可以与感应线或者驱动线 11保持隔绝, 大大降低了影响 触摸屏的静态的漏电流。 可以有效解决 ESD 保护电路的静态漏电流对 TFT-LCD触摸屏的影响。 同时, 也了保证共电极母线, 或 ESD放电母线, 或 接地母线 12与感应线或者驱动线 11保持隔绝,从而避免感应信号或驱动信号 通过感应线或驱动线泄露到触摸屏周边的共电极母线, 或者 ESD放电母线和 接地母线 12上, 从而增大触摸屏的功耗。
参见图 9, 该图为本发明提供的触摸屏的 ESD保护装置实施例五示意图。 本实施例提供的触摸屏的 ESD保护装置中, 所述保护开关为低温多晶硅 ( LTPS , Low temperature poly silicon )、硒化镉 CdSe或者氧化物半导体(如: 氧 化铟镓辞 IGZO, Indium Gallium Zinc Oxide )的双栅极 TFT, 所述双栅极 TFT 中的顶栅极和底栅极分别被互为反相的两个控制脉冲控制。这样顶栅极和底栅 极可以同时控制下面的电子沟道, 外部输入反相的脉冲控制顶栅极和底栅极, 在电子沟道处相互抵消从而双栅极 TFT一直处于关断状态。
需要说的是, 本发明以上实施例提供的触摸屏的 ESD保护装置中, 所述 保护开关和显示器的 TFT阵列同时制作在一张基板上。
需要说的是, 本发明以上实施例提供的触摸屏的 ESD保护装置可以应用 于二维图像接收器或者二维图像釆集器上。 例如 X射线图像传感器上, 或者 二维触摸屏上。
以上所述,仅是本发明的较佳实施例而已, 并非对本发明作任何形式上的 限制。 虽然本发明已以较佳实施例揭露如上, 然而并非用以限定本发明。 任何 熟悉本领域的技术人员, 在不脱离本发明技术方案范围情况下, 都可利用上述 揭示的方法和技术内容对本发明技术方案做出许多可能的变动和修饰 ,或修改 为等同变化的等效实施例。 因此, 凡是未脱离本发明技术方案的内容, 依据本 发明的技术实质对以上实施例所做的任何简单修改、等同变化及修饰, 均仍属 于本发明技术方案保护的范围内。

Claims

权 利 要 求 书
1、 一种触摸屏的 ESD保护装置, 其特征在于, 包括:
ESD保护电路和与 ESD保护电路串联的保护开关;
当触摸屏的感应线或驱动线的静电电位大于或等于预设电位时,所述保护 开关导通, 所述 ESD保护电路和保护开关形成通路, 用于将感应线或驱动线 的静电泄露到周边的共电极母线, 或 ESD放电母线, 或接地母线上去;
当所述触摸屏的面板正常驱动时, 所述保护开关断开。
2、 根据权利要求 1所述的触摸屏的 ESD保护装置, 其特征在于, 所述保护开关连接在所述 ESD保护电路和触摸屏的感应线之间; 或 所述保护开关连接在所述 ESD保护电路和触摸屏的驱动线之间; 或 所述保护开关连接在所述 ESD保护电路和 ESD放电母线之间; 或 所述保护开关连接在所述 ESD保护电路和接地母线之间; 或
所述保护开关连接在所述 ESD保护电路和共电极母线之间。
3、 根据权利要求 1 所述的触摸屏的 ESD保护装置, 其特征在于, 所述 ESD保护电路至少包括一个保护开关。
4、 根据权利要求 2所述的触摸屏的 ESD保护装置, 其特征在于, 所述保 护开关为一个第三薄膜晶体管 TFT, 所述第三 TFT的控制栅极连接控制脉冲, 同时所述第三 TFT的控制栅极通过另外一个 ESD保护电路或者电阻性器件连 接到接地母线, 或者共电极母线, 或者 ESD放电母线上。
5、 根据权利要求 1所述的触摸屏的 ESD保护装置, 其特征在于, 所述保 护开关包括串联在一起的第四薄膜晶体管和第五薄膜晶体管,所述第四薄膜晶 体管和第五薄膜晶体管的控制栅极被互为反相的两个控制脉冲控制;所述第四 薄膜晶体管和第五薄膜晶体管均为 PMOS管或者均为 NMOS管。
6、 根据权利要求 1所述的触摸屏的 ESD保护装置, 其特征在于, 所述保 护开关包括串联在一起的两个 TFT, 其中一个 TFT为 NMOS管, 另一个 TFT 为 PMOS管, 所述 NMOS管和 PMOS管的栅极用同一个控制脉冲控制。
7、 根据权利要求 1所述的触摸屏的 ESD保护装置, 其特征在于, 所述保 护开关为低温多晶硅 LTPS、 硒化镉 CdSe或者氧化物半导体的双栅极 TFT, 所述双栅极 TFT中的顶栅极和底栅极分别被互为反相的两个控制脉冲控制。
8、 根据权利要求 1 所述的触摸屏的 ESD保护装置, 其特征在于, 所述 ESD 保护电路包括至少一对薄膜晶体管, 所述一对薄膜晶体管包括以背靠背 方式连接的第一薄膜晶体管和第二薄膜晶体管。
9、 根据权利要求 8所述的触摸屏的 ESD保护装置, 其特征在于, 所述 ESD 保护电路的多对薄膜晶体管可以以串连、 并联或串连并联相结合的方式 连接。
10、 根据权利要求 1-9任一项所述的触摸屏的 ESD保护装置, 其特征在 于,所述 ESD保护电路与保护开关和显示器的 TFT阵列制作在同一张基板上。
11、根据权利要求 10任一项所述的触摸屏的 ESD保护装置,其特征在于, 该 ESD保护装置应用于二维的空间图像成像器件上;
或者探测二维空间的基于机械触摸和压力的传感器上;
或者基于声波、光波或者电磁波的直接或间接作用产生的二维空间信息的 传感器上。
12、 根据权利要求 10所述的触摸屏的 ESD保护装置, 其特征在于, 所述 TFT阵列用于驱动液晶显示器或者有机发光二极管阵列。
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