Recently, projected capacitive type touch panel with characteristic of multi-input by fingers has been drawing attention. Projected Capacitive Touch Panel is also referred to as "PCAP". GUNZE designs and sells variety of customized products using PCAP technologies.
Method and Structure
Capacitive touch panel is a type of touch panel which captures minor electrical alteration of finger input.
It consists of transparent electrode films which electrodes are patterned vertically & horizontally and detect input location by identifying where electrical alternation occur using IC (touch panel controller). (Fig.1)
Adjustment of input position to be detected just by bringing finger close to the surface of sensor without actually finger directly touching the sensor is possible, and this enables using materials such as glass as cover material which is placed on the input surface side making designable touch panel having durability against scratch with better environmental resistance.
In term of configuration of capacitive touch panel, it is the same as matrix type which electrode patterns of horizontal and vertical are in reticular patterns, and insulation between electrode patterns on the conductive layers is considered as condenser.
There are 2 different electrode patterns for the sensor where grid patterns are linear and diamond. Appropriate capacitance of insulator (dielectric substance) is obtained when voltage is applied to electrode patterns which lie next to each other and potential difference occurs between the electrodes.
Since human body contains high water content and have electrical conductivity, capacitance between electrodes increase when finger comes near the sensor detecting input coordinate by identifying capacitance where horizontal (x) and vertical (y) lines change. (Fig.1)
Advantage of Film Material
Typical materials used to designing capacitive touch panel are glass and film. GUNZE has developed film-based projected capacitive touch panel taking advantage of in-house film material development. Film-based projected capacitive touch panel may be offered with advantages of thinness, lightweight, reasonable price, and ease of bonding process when compared to glass-based projected capacitive touch panel. (Fig.2)
COF (Chip On Flexible Prited Circuit) Technology
COF stands for "Chip On Flexible Printed Circuit" and is a mounting technology where IC chip is mounted directly on top of Flexible Printed Circuit. This technology has an advantage of making IC mounting area smaller as it is suitable for miniaturization of capacitive touch panel when applying it to product. (Fig.3)
Film-based capacitive touch panel is used with placing cover material on the housing considering the design of final product and improving the durability.
GUNZE may design and offer distinctive touch panel designing using great variation of cover materials such as glass, acrylic board, decorative cover with black printing, IMT(Insert Molding Transcription), and functional film (anti-finger print film, AR film, and HD(High Durability) film. (Fig.4)
Multi-Touch (Simultaneous Multi -Input)
In order to have multi-touch with traditional resistive touch panel, it is done by software process.
When 2 points on resistive touch panel is touched simultaneously, position in the middle is detected. With this characteristic, processing the data by time-lag of 2 positions makes resistive touch panel to have multi-touch. Because of its detection principle, resistive touch panel is unsuitable for gesture operation as input force is necessary in order to make upper and lower conductive layer contact each other.
As for multi-touch on capacitive touch panel, simultaneous multi-input of 3-point or more is possible by structure of sensor (hardware).Smooth slide input and stress less gesture operation are possible as input position of capacitive touch panel is detected without finger contacting the surface of sensor, but putting finger close to the surface of sensor.(Fig.5)
Touch Panel Controller
IC (Touch Panel Controller) used with GUNZE capacitive touch panel is available in forms of chip only, COF(Chip On Flexible Printed Circuit) where chip is mounted onto Flexible Printed Circuit, and controller board with peripheral circuit. Please select one from these 3 configurations which suits the best to your product.
As development of the controller is headed to have high functional performance, it has progressed from single touch to multi-touch gesture, and to multi-touch all point. GUNZE offers customers capacitive touch panel along with controller that meet the requirement of customers. (Fig.3)
Window Logo Certification
PC operation has become simple and easy with the appearance of gesture operation which Microsoft "Windows 7" supports.
GUNZE has developed 15.0" film-based capacitive touch panel prior to other companies and also developed IC (Touch Panel Controller) which detect the input location in parallel with the development of touch panel and achieved to have multi-touch input. GUNZE obtained "Windows Touch" certification for "Windows 7" with these 2 products.
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