In-Cell触摸屏设计及工艺(陈悦)

1、In-Cell触摸屏设计及工艺,Integrated touch panel category,Integrated touch panel includes structures below: 1. resistive type 1.1 integrate traditional resistive touch panel on-cell 1.2 integrate resistive touch panel in-cell (Samsung) 2. capacitive type 2.1 capacitance changed by deformation of top glass in-

2、cell (AUO, Samsung, Epson) 2.2 capacitance changed by induced current from finger 2.2.1 integrated surface capacitive touch panel on-cell 2.2.2 integrated projective capacitive touch panel on-cell (AUO, CMO, Wintek) 2.2.3 integrated projective capacitive touch panel in-cell 3. optical type in-cell (

3、AUO, LG, Sharp, TMD),Optical type in-cell TP,光学in-cell触摸屏是在LCD TFT array基板上集成进一些光敏器件。有两种工作方式，一种如下图：靠激光笔的光被光敏器件感应以确定位置。另一种是用手指遮挡环境光从而使光敏器件感应。 但这两种方式都有较大限制。,Optical type in-cell TP,TMD, AUO, LGD, Sharp均有光学内嵌触摸屏样品面世。,Integrate traditional resistive touch panel on-cell,Touch panel structure and driving

4、circuit is same to traditional 4-wire or other resistive touch panels. Compared with non-integrated touch panel, this structure removed one glass layer.,Integrate resistive touch panel in-cell,This integrate type has some different structures, includes: Samsung structure Filed patent (US20070070047)

5、 have SID paper (SID08 55.1) made a demo in 2007 Philips structure Filed patent(US20060262099) have SID paper (SID04 3.5),In-cell resistive touch panelsamsung(1),Basic principle: When pressed, the sensor switch is on (conductive column spacer contact sensor electrode) From plan view, at touch point,

6、 common electrode contact two sensing lines perpendicular with each other respectively,In-cell resistive touch panelsamsung(2),One possible structure is like below. Use one column spacer contact 2 sensing electrodes simultaneously. So at the touched point, X sensor line and Y sensor line connected t

7、o the common electrode. From Philips research, the top glass need to be polished to 0.2mm to get a 0.3um cell gap displacement by a 0.15N force.,In-cell resistive touch panelsamsung(3),Layer structure can be like below, sense line 1 use gate metal, sense line 2 use S/D metal, sense lines contact sen

8、se electrodes (on the pixel ITO) through via.,In-cell resistive touch panelsamsung(4),Detect method: Detect X and Y respectively and get the touch position. Detect method is to compare the line signal to a reference voltage to determine if there is a finger touch.,Capacitive touch panel (压力式),This i

9、ntegrate type has some different structures, includes: Cell gap change type Samsung filed a patent (US20080048994). AUO has made a demo. LC alignment change type Samsung filed patent (US20050094038) very early, but Samsungs demo applied another detect circuit (SID07 24.3), and Epson made a demo (SID

10、08 55.2) based on Samsungs structure by using LTPS, IPS and active matrix sensor so that improved the performance.,Cell gap change type,Samsungs patent (US20080048994) only posed a basic principle, its layer structure and detailed detect method is not shown in the patent. Though AUO has made a demo,

11、 there are very few open materials of its detect principle. They use the same principle: detect the capacitance change between common electrode and sense electrode by cell gap deformation. There are many ways to detect capacitance change, which way Samsung and AUO used is unknown.,AUO,Samsung,Cell g

12、ap change type,AUO和LG的压力式内嵌触摸屏样品,LC alignment change typeSamsung(1),Samsungs patent (US20050094038) first proposed this method: Because different LC alignment has different dielectric constant, and when pressed, the LC alignment is changed, so that the LC capacitance changed.,LC alignment change typ

13、eSamsung(2),Samsungs demo use this structure: Each line sensor is placed every 8 pixels. Each sensor line connect with many dummy LC pixels and many reference capacitors. Dummy pixels are all covered by black matrix. When LC capacitance changed, the voltage between Clc and Cref also changed, so the

14、touch position can be determined.,LC alignment change typeSamsung(3),The sequence of each detection is: First close sw1, apply Va to LC and initialize the alignment of LC (this will take several milliseconds). Then, apply Vb to LC to set the voltage bias to amplifier operating condition (to prevent

15、saturation of charge amplifier). Finally, read out the voltage change of node between Clc and Cref to detect a finger touch.,LC alignment change typeSamsung(3),Samsung和Epson的in-cell LC alignment change type TP,Samsung,Epson,Integrate surface capacitive touch panel(1),Surface capacitive touch panel p

16、rinciple: Touch point is treated as connecting to ground by a capacitor. The resistor from touch point to 4 corners R1-4 is related to the distance from touch point to 4 corners. The more the distance is, the more the resistor is. When add sine signal on 4 corners, the current at 4 corners I1-4 is i

17、nverse proportion to related R1-4. By measuring I1-4, the touch point can be detected.,Integrate surface capacitive touch panel(2),Touch panel structure and driving circuit is same to traditional surface capacitive touch panel. Compared with non-integrated touch panel, this structure removed one gla

18、ss layer.,Integrated projective capacitive touch panel on-cell,So far, Apple filed integrated PCT patent (US20080062148), but have not made demo yet. Apples patent used mutual capacitance technology. AUO, CMO, Wintek all exhibited demos of on-cell capacitive TP On-cell TP has at least one working la

19、yer above LCD CF glass.,AUO,Apple,Integrated projective capacitive touch panel on-cell,AUO, CMO on-cell capacitive touch panel.,Integrated projective capacitive touch panel on cell structure,These are 3 different on-cell structure proposed in apples patent application. The detect method of Apples in

20、tegrated type PCT is same to mutual capacitance detect method described before. The layer structure can be as follows. Structure 1: Integrated Apples PCT directly onto LCD top glass.,Integrated projective capacitive touch panel on-cell,Structure 2: Sense layer (ITO1) is above the top glass, and drive lines and common electrode share a same ITO (ITO2), Vcom and Vdrive applied on different drive lines (common ITO) at the