2. DCC Introduction(1)
The Principle of Capacitive Touch
Allow design flexibility:
– Free from pad size, pad location, cover thickness, PCB variation
– Capable of on-board, not on additional board
Result in same sensitivity all the time
Insulator (Set cover)
Touch PAD (Copper)
A
PCB CTouch = ε
DCC D
Ctouch: The capacitance induced between finger and touch pad when touched.
ε : the constant value of permittivity (Air=1,Glass= 10, Acryl=5~10, Rubber=2~3)
D : The thickness of Set Cover
A : The size of Touch Pad
3. DCC Introduction(2)
Touch Operation of DCC
Case of Finger Touch Not Presented:
(a) Touch PAD System Model, (b) Impedance Status
Impedance Zin
Zin Change Finger not
Detection present Zref
Zref
(a) Zref > Zin (b)
Case of Finger Touch Presented:
(a) Touch PAD System Model, (b) Impedance Status
Ztouch
Impedance Zin
Zin Change
Finger
Detection present Zref
Zref Ztouch
(a) (b)
4. ITO Introduction
ITO (Indium Tin Oxide) Specification
• Construction
Protection Film
ITO(100~200Å)
Under coat Layer
Hard coat Layer
PET File(175um)
Hard coat Layer
• Transmittance: 88%
• Total Thickness : 0.2mm
• Surface Resistance: 450+/-120Ω/sq
• Patten Pitch Length
5. ITO touch with DCC solution
ITO Touch Module
DCC
Main Board
DMB
Attaching
MCU
NAV
MP3
OK
FPC
ITO Sensor Screen
