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 to sense a generation of touch capacitance Ct by approaching a touch input device of a finger of a human body or a conductor similar to the finger to the display device, the touch detection apparatus comprising:
a touch pad configured to form the touch capacitance Ct between the touch pad and the touch input device;
a driving capacitor Cdrv, wherein one portion of the driving capacitor Cdrv is connected to the touch pad and the other portion of the driving capacitor Cdrv is applied with a driving voltage for touch detection;
a touch detector configured to be connected to the touch pad and detect a touch signal using a driving back phenomenon when the touch capacitance Ct is added to the driving capacitor Cdrv depending on whether the touch input device is touched; and
a memory unit configured to store the touch signal detected by the touch detector, wherein the memory unit includes a plurality of line memories which bundles and simultaneously stores the touch signals of the touch pad in any one of a horizontal direction or a vertical direction of the touch pad,
wherein a voltage detected by the touch detector at the non-touch time is determined by the following <Equation 1>, when the touch capacitance Ct 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
)
C
ⅆ
rv
C
ⅆ
rv
+
Cvcom
+
Cp
<
Equation
1
>
Δ
Vsensor
=
Vpre
±
(
Vh
-
Vl
)
C
ⅆ
rv
C
ⅆ
rv
+
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, Vl 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.
2. The touch detection apparatus of claim 1 , wherein the touch detector detects a touch area of the touch input device for the touch pad in response to a size of the driving back.