Touch detection device, touch detection method and touch screen panel, using driving back phenomenon, and display device with built-in touch screen panel
Provided is a touch detection device, touch detection method, and touch screen panel, which detects a touch signal by detecting a driving back phenomenon occurring in a touch pad by a driving voltage applied to a driving capacitor, and a display device with a built-in touch screen panel. The touch detection device that is added on top of a display device and detects occurrence of a touch capacitance (Ct) by an approach of a bodily finger ( 25 ) or a touch input instrument such as a conductor similar to the bodily finger, the touch detection device comprising: a touch pad ( 10 ) that forms the touch capacitance (Ct) between the touch input instrument and the touch pad; a driving capacitor (Cdrv) whose one side is connected to the touch pad ( 10 ) and to the other side of which a driving voltage for detection of a touch input is applied; a common voltage detector that detects a common voltage generated from the display device; a driving voltage generator that generates the driving voltage in synchronization with the common voltage; and a touch detector that is connected to the touch pad ( 10 ), and that detects a touch signal by using a driving back phenomenon when the touch capacitance (Ct) is added to the driving capacitor (Cdrv) according to occurrence or non-occurrence of a touch in the touch input instrument. A touch signal is detected while avoiding a point in time of a change of a common voltage state, and a driving voltage is applied through a driving capacitor connected to a touch detector, to thus detect whether or not a driving back phenomenon occurs in the touch detector and to thereby acquire a touch signal. Accordingly, an influence due to parasitic capacitance generated by noise, coupling phenomenon or other factors is minimized, to thus acquire a touch signal stably.
1. A touch detection apparatus installed in a display device, the touch detection apparatus comprising:
a plurality of touch pads configured to form a touch capacitance by approaching a touch input device to the display device;
a plurality of sensor signal lines connected to the plurality of touch pads, respectively;
a touch drive IC (TDI) receiving a plurality of touch signals from the plurality of touch pads through the plurality of sensor signal lines, respectively;
a driving capacitor, wherein one portion of the driving capacitor is connected to the touch pads and the other portion of the driving capacitor is applied with a driving voltage for touch detection; and
a driving voltage generator configured to generate the driving voltage,
wherein the plurality of the touch pads are arranged in a dot matrix within a display region of the display device,
wherein a line width of a sensor signal line as well as a line length of the sensor signal line is getting greater as a distance between a corresponding touch pad and the TDI is increased, and
wherein the TDI detects a touch signal using a driving back phenomenon when the touch capacitance is added.
2. The touch detection apparatus of claim 1 , wherein the driving voltage generator is included in the TDI.
3. The touch detection apparatus of claim 2 , wherein a touch pad is connected to a touch detector of the TDI.
4. The touch detection apparatus of claim 3 , further comprising a charging device for applying a precharge voltage, wherein the charging device is connected to the touch pad.
5. The touch detection apparatus of claim 4 , wherein the charging device is a switching device and an output unit of the switching device is in a high impedance state at the time of the touch detection.
6. The touch detection apparatus of claim 2 , wherein the TDI comprises a touch detector that detects the touch signal when a predetermined period lapses after the driving voltage is applied.
7. The touch detection apparatus of claim 2 , wherein a voltage detected by a touch detector of the TDI at the non-touch time is determined by the following <Equation 1>, when the touch capacitance is added, the voltage detected by the touch detector is determined by the following <Equation 2>, and the driving back is generated by a difference between the <Equation 1> and the <Equation 2>,
Δ
Vsensor
=
Vpre
±
(
Vh
-
Vl
)
Cdrv
Cdrv
+
Cvcom
+
Cp
〈
Equation
1
〉
Δ
Vsensor
=
Vpre
±
(
Vh
-
Vl
)
Cdrv
Cdrv
+
Cvcom
+
Cp
+
Ct
,
〈
Equation
2
〉
wherein, in the Equation 1 and Equation 2, ΔVsensor represents the voltage detected by the touch detector, Vh represents a HIGH level voltage applied to the driving capacitor, V 1 represents a LOW level voltage applied to the driving capacitor, Cdrv represents a driving capacitance of the display device, Cvcom represents a common electrode capacitance of the display device, Cp represents a parasitic capacitance of the display device, and Ct represents the touch capacitance.
8. The touch detection apparatus of claim 1 , wherein as a distance between a touch pad and the TDI is increased, a separate distance between a corresponding sensor signal line and a next sensor signal line adjacent thereto is also increased.
9. The touch detection apparatus of claim 8 , wherein the increased separate distance between the sensor signal line and the next sensor signal line adjacent thereto is full of a space filling element.
10. The touch detection apparatus of claim 1 , further comprising a common electrode capacitor, wherein the common electrode capacitor is formed between the touch pads and a common electrode of the display device.
11. The touch detection apparatus of claim 1 , wherein a sensor signal line is positioned at left and right sides of a corresponding touch pad.
12. The touch detection apparatus of claim 1 , wherein touch pads which do not perform touch detection are in a floating state.
13. The touch detection apparatus of claim 12 , wherein the touch pads which do not perform the touch detection are entered into the floating state before a charging device of a touch detector of the TDI is turned on.
14. The touch detection apparatus of claim 1 , wherein, in a region where the sensor signal lines are not formed, a space between the touch pads is narrower than the size of a pixel of the display device.
15. The touch detection apparatus of claim 1 , wherein a space between the sensor signal lines is narrower than the size of a pixel of the display device.