Know-how on #CTP #TouchPanel

Touch panel includes capacitive touch panel (also named #CTP) and resistive touch panel (also named #RTP), which is known to all of us. In this article, we have more full know-how on capacitive touch panel to share.

Firstly, touch panel structure, it include G+G, G+F, G+F+F. For normal CTP, under the cover glass (also named cover lens), there is a sensor glass or ITO film as touch sensor, playing the role of touch sensing.

G+G(glass-glass) use two layers of glass to form the touch panel. The touch sensor is sandwiched between two layers of glass, and the layers are fused together to create a single panel. This type of #touchscreen main feature is high #transparency and #durability.

G+F (glass-film) use one layer of glass as the top layer, and one layer of ITO film as the bottom layer. The touch sensor is placed on top of the film #layer. This type of touchscreen is thinner and lighter than G+G, but it may not be as durable.

G+F+F (glass-film-film): use two layers of film along with a layer of glass. The touch sensor is placed on top of the top film layer. This type of touchscreen is even #thinner and #lighter than G+F, but it may not be as durable as G+G.

Secondly, cover glass brand.

Normally for those product not with high requirements, we use AGC #coverglass. But some customer might have high demands, such as vandal-resistant and high-end laptop, Corning brand is more fittable, undoubtedly the cost is higher.

Thirdly, surface treatment. It includes AG, AR, AF.

#AG (anti-glare) Coating Processing: The process involves depositing a layer of material with a rough surface onto the surface of the #screen. This can be done using a variety of techniques, including etching, sandblasting, or chemical treatment. The rough surface of the coating scatters light, reducing glare and reflections. It could make it easier to view the screen in bright lighting or sunshine conditions.

#AR (anti-reflective) Coating Processing: The process for applying an AR coating typically involves depositing a thin layer of material onto the surface of the screen. This layer is designed to have a refractive index that is intermediate between that of air and the screen material, which reduces the amount of light that is reflected off the surface of the screen. The thickness and composition of the layer can be optimized to minimize reflection over a specific range of wavelengths. It could improve the clarity and visibility of the display, the highest transmittance could be achieve 99%.

#AF (anti-fingerprint) Coating Processing: The process for applying an AF coating typically involves depositing a thin layer of material onto the surface of the screen that has hydrophobic (water-repelling) and oleophobic (oil-repelling) properties. This can be done using a variety of techniques, including chemical vapor deposition or plasma-enhanced chemical vapor deposition. The coating creates a surface that resists the deposition of oils and other contaminants from skin, reducing fingerprint smudges. It has strong hydrophobicity, anti-oil, anti-fingerprint and other functions. It can easily wipe off dirt, fingerprints, oil, etc., so as to keep the screen clean and smudge-free.

Fourthly, CTP's FPC.

The pin mapping is customizable per needs. The #FPC could be solded into the tft display's FPC, or comes out along in any position, according to customer demand.

Fifthly, color OCA effect and normal OCA.

Normal #OCA means when lcd display not turning on, the screen shows its original color, such as white or grey. But lately touch panel vendor has found a new technology for CTP, called #colorOCA. It use #blackOCA glue to bond the tft display and CTP or spray a black UV on the cover lens surface, to make it look dark when display not turning on. If you choose black OCA glue, you'd better use #IPS TFT LCD and the optical bonding, because #TN and air bonding will lower the darking effect. At the same time, the lighting transmittance of color OCA bonding is 50-60%, which strictly requires the original tft lcd has high #brightness.?

Sixthly, bonding method.

To bond touch panel to the TFT display, there are two methods, one is #opticalbonding (also called full lamination), another is #airbonding (also called half lamination). Vendor use double sided tape (normal brand is Sekisui) for air bonding. Optical bonding available glue are OCA and OCR/LOCA glue. OCR is for high-end product and high requirements on the touch panel performance, such as automotive and medical etc. OCA glue is wider applied for optical bonding of capacitive touch panel, what's more, bonding from sensor glass to cover glass, it normally use OCA glue.

Seventhly, touch IC.

It not only affect the operating speed, also it's something related to the bonding method, for example, for some touch ic is compatitable with optical bonding or not. The normal brand for touch IC are Atmel, Synaptics, EETI, Focal Tech, Goodix etc. Also some touch IC could support capacitive touch with gloves or water drop on the CTP, such as #eeti ic, but some touch IC don't support that.

Above is the simple know-how on capacitive touch panel for all friends in electronics industry, such as smart home, industrial monitor, handheld equipment, kitchen device, human machine interface, IoT, automotive, medical market. Further, if you need professional lcd solutions, including customized #touchpanel, #FPC (flexible printed circuit), #FFC, #backlight, #coverlens, color OCA or any other special requirements, welcome contact us(#LCDfactory) @whatsapp/skype/wechat +86 17876137566.