Touch and Sense ASIAPRO
4-Wire Resistive Touch
盈科科技興業有限公司
AsiaPro Technology Enterprise Ltd.
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Touch panels and touch windows

Resistive Touch Panels

Resistive touch panel (RTP) is one of the most popular touch sensors to be used in the electronic consumer markets. Resistive touch panel provides very user-friendly interface, it can be input by fingers or stylus or gloved hand. Because of its simple structures, well-develop controller ICs, more mature technology, and fewer patent restriction, cost is relatively low. The analog resistive technology is perfect for PDAs, web phones, and other handheld consumer applications.

The mechanism of resistive touch panel locating the touch point is by calculating and comparing the resistance and voltage of the relative position on the panel. Resistive touch panel is formed by two pieces of ITO (Indium Tin Oxide) conductive base material, typically PET film and glass. In between the two layers of conductive bases, there are spacing dots, which is a kind of very tiny transparent insulation particles. When a pointed insertion force, either press with a finger or by a pointer, applies on the two conductive bases, an instance change of voltage will be happened and the pointed position is calculated thereby.


ASIAPRO provides superb quality and cost effective resistive touch panels, including:

  • 4-wire Resistive Panels
  • Resistive Touch Windows

4-wire analog resistive

The 4-wire analog resistive type makes up most of the touch panel products in the market. It has a film type top layer and a rigid glass bottom layer separated by insulating spacer, with the inside surface of each layer coated with transparent ITO conductive. Voltage applied to the layers produces a gradient across them. By pressing the top layer film sheet, it creates electrical contact between the two resistive layers, essentially closing a switch in the circuit, controller then read the voltage gradient horizontally and vertically to get X and Y coordinates , so the position is determined and displayed.

Matrix resistive

The construction of matrix (or digital) touch panel consists of two transparent ITO conductive coating layer, typically film and glass, that is patterned in rows and columns of pre-determined width to make up discrete switches. By calculating the loop resistance value, which is affected by the screen’s sheet resistance and patterns, the press position is determined.


Multi-touch resistive

Multi-touch resistive is a kind of touch sensor evolved from the matrix resistive touch panel. It employs the basic principal of the matrix resistive construction. It also has two ITO patterned layers separated by spacing dots. Usually the top layer has ITO columns and bottom layer has ITO rows. When the two layers are put together, each intersection of the columns and rows forms an independent touch sensor. The controller will then detect the change of voltage at every individual intersection point. Such multi-touch technology allows users operate with protective gloves. This makes it ideal for industrial and field professionals who work with dangerous chemicals or perform their job in extreme weather conditions. Even with gloves, the sensitivity and accuracy of the multi-touch screen is high.

Touch panels and touch windows

ASIAPRO Touch Window

ASIAPRO Touch window or Touch lens is made by merging a decorative film with an analog resistive touch panel. This technology enables circuits to be hidden, and directly mount on the product. As the top layer is made of a PET film, it permits a flat surface for user interface, as well as provides flexibility on the shape designs, it also makes touch panel becoming part of the product outlook, thus gives more options for designs. ATW can replace lens as part of the face cover which comes with touch input function, allowing you to meet trends in the reduction of product sizes and thickness, and improvements in display quality. ASIAPRO Touch window also delivers cost-effective option, consistency and durable performance for devices designed to withstand contaminants and liquids in the environment.




Touch panels and touch windows

Resistive Touch Panels Specifications


Material options
ITO glass 0.55, 0.7, 1.1, 2.0, 3.0 mmt, tempered glass
Film

0.175/0.188 mmt; Single layer/double layers
Hard coat;
Glare, Anti-glare; Anti-reflection; Anti-Newton ring; Anti-finger print

Lens(PET) 0.125 - 2.0 mmt

Supporting
PC/PMMA

0.55 - 2.0 mmt
Supporing glass 0.4 - 3.0 mmt; Tempered glass


Operation and storage conditions:
Items Conditions
Operation temperature -20°C ~ +70°C (RH≦90% & no dew condensation)
Storage temperature -30°C ~ +80°C (RH≦90% & no dew condensation)


Electrical properties
Items Specifications
Rating (maximum voltage) DC 5V(DV 7V max.)
Insulation resistance ≧20MΩ (DC 25V, 1 min)
ESD ±8.2KV
Chattering time ≦10ms


Linearity
Items Specifications
Linearity ≦±1.5% (X & Y directions. After reliability test)


Mechanical properties
Items Performance Remarks
Input methods Exclusive pen:
10-100gf
Stylus pen
Tip material: POM (Polyacetal)
Tip radius: R0.8 mm
Finger:
10-100gf
Use below material to simulate finger for testing: Material: silicone rubber(Hardness: 30° HS )
Tip radius: R12.5 mm
Surface Hardness ≧3H Pencil hardness. Force 500gf


Optical properties
Items Performance
Total light transmittance 78% - 83%
Haze ≦10%
Film features

Hard coat; Anti-Glare; Anti-Reflection;
Anti-Newton ring; Anti-Finger print



Reliabilty testings
Items Performance (Conditions)
Hitting durability ≧1,000,000 hit (POM pen: R1.0, 60°, 250gf at 2/sec)
Sliding durability ≧100,000 slide (POM pen: R1.0, 60°, 250gf at 100mm/sec)
Impact resistance 1.5m (for 0.7mmt glass; steel ball: 5.5g, dia.Ø11mm)
1.8m (for >=1.1mmt glass; steel ball: 5.5g, dia.Ø11mm)
High temperature reliability (1) Temp.80°C(≤RH50%, no dews allowed), for 240hrs; then
(2) Place under room temp for 24hrs;
Low temperature reliability

(1). Temp.-30°C, for 240hrs; then
(2). Place under room temp for 24hrs; (no dews allowed);

High temperature & high humidity test (1). Temp.60°C, ≤RH90%(no dews allowed), for 240hrs; then (2). Place under room temp for 24hrs;
Thermal shock test

(1). -30°C(30mins)→raise temp(10mins)→80°C(30mins) →lower temp(10mins) total 50cycles; then
(2). Place under room temp for 24hrs(no dews allowed)

Thermal cycle test (1). -30°C(2hrs)→raise temp(1hr)→80°C(2hrs)→lower temp(1hr) total 50cycles; then
(2). Place under room temp for 24hrs(no dews allowed)
FPC bending durability (1) Attach a load 100gf to the end of FPC; then;
(2) Bend the FPC with 180° x 5 times as shown.
FPC bonding peeling strength tests (1). Attach a load 500gf to the end of FPC; then
(2). Bend the FPC in 90° to ITO FILM direction as shown, keep for 5mins.
(1). Attach a load 500gf to the end of FPC; then
(2). Pull the FPC in 180° direction as shown, keep for 10mins.
Above are general specifications and not guarantee , performances may vary with structure, touch  IC & material used, should take proper testing before use.

Resistive touch panels structure

How Resistive Touch Works

4-Wire Resistive Technology

A resistive touch panel is a mechanical sensor. It consists of 2 conductive ITO layers separated by air gap and tiny transparent insulation spacer dots. When a finger or stylus presses on the top layer of ITO PET film (usually X axis), which means that it physically touches the lower layer of ITO glass substrate (usually Y axis), the voltage at the contact point is measured through the 4-wire printed on the edges of both ITO layers, and then the location can be computed by the controller. After the finger or stylus releases, the top layer resumes to its original position.









ASIAPRO offers a wide range of resistive touch constructions: