Definition of Terms

ACF and ACP

Anisotropic Conductive Films (ACF) and Anisotropic Conductive Paste (ACP) are interconnect systems used in LCDs and Touchscreens to provide Z-axis electrical connection between conductors on a substrate and a bonded tail.


Actuation Force

Actuation force is defined as the minimum force required to positively activate a touchscreen.


Anti Glare Coating

In order to reduce glare and or reflection on a surface a coating is applied which reduces the smoothness of the surface and hence reduces glare. The glare reduction is achieved by scattering of the incident light. Most anti glare coatings also act as a hard coating.


Anti Newton Rings (ANR)

Newton Rings appear in resistive touchscreens due to the proximity of the smooth surfaces of the top and bottom layers. To eliminate these rings ANR films are used. These films have a layer of Anti Glare coating deposited under the ITO coating to provide texture to the surface and eliminate the Newton Rings.


Anti Reflective Coating

A coating applied to the surface of a film or glass to reduce reflection of the incident light. Anti reflective coatings are typically made of many layers transparent thin film coatings.


Bonded Tail

A bonded tail is a discrete component bonded or attached to the touchscreen via ACF and ACP.


Buffer Layer

Buffer layer or an overlay is a layer of film optically bonded on the top layer of a resistive touchscreen to provide additional strength.


Busbar

A conductive ink printed or deposited on transparent conductive surfaces to provide means for transmitting electrical currents between the touchscreen and the controller.


Controller

An electronic circuit designed to act as an interface between the touchscreen and the host computer. The controller translates voltage information received from the touchscreen to positional information.


Dots

Small (0.002" to 0.010" diameter) dielectric dots used to separate the top and bottom layer of a resistive touchscreen and to prevent unwanted and accidental touches.


ELTT

Enhanced Light Transmission Touchscreen.


EMI

EMI or Electro Magnetic Interference is a disturbance that interrupts, obstructs, or otherwise degrades or limits the effective performance of electronics and electrical equipment.


ESD

ESD or electrostatic discharge is the sudden and momentary electric current that flows between two objects at different electrical potentials. These currents can possibly damage electronic components.


Film

Optical grade plastic, typically PET or Mylar used in manufacturing of resistive touchscreens.


Gasket (Iinternal)

A layer of double sided pressure sensitive adhesive (PSA) used to attach top and bottom layers of a resistive touchscreen.


Glass

Various thicknesses of ITO coated glass or bare glass used as a substrate and the bottom layer of a resistive touchscreen. When used uncoated it is used as a substrate to provide a rigid touch surface.


Gloss

Gloss value is a measure of the amount of reflected light from the surface of a material compared to that of a black calibration glass. The gloss value of the standard black glass is defined as 100. The value obtained for a particular material may be lower or higher than 100. A low value suggests a less reflective surface and a high value a more reflective surface. Gloss value is also a measure of surface smoothness or roughness.


Hard Coat or Hard Coating

A coating applied to the surface of a film to provide protection against scratches and abrasions. Hard coatings may be clear/glossy or they may have anti glare properties.


Haze

As light passes through a transparent material it may get scattered due to composition or surface texture of the material. This scatter produces a hazy field when objects are viewed through the material. Haze measurement defines the level of scattering of light passing through a material which causes a reduction of contrast.


Integrated Tail

An integrated tail is one that is an extension of the touchscreens layer or layers.


ITO

ITO or Indium-Tin-Oxide is a transparent and conductive metal oxide. This material is sputtered onto glass, PET or other optical films used in manufacturing of resistive touchscreens.


Light Transmission

Light transmission is defined as the percentage of the incident light that passes through a transparent material. Light transmission is typically measured at a specific wavelength or a range of wavelengths.


Newton Rings

Newton Rings are optical interference patterns caused by the reflection of the light between two smooth and surfaces.


Non-linearity (Average)

Linearity is the relationship between two physical quantities where a change in one produces a proportional change in the other. In terms of resistive touchscreens, ideally the relationship between voltage received from the touchscreen and the location of the touch must be proportional. However due to coating non-uniformity, scratched surface or other reasons, this relationship may be disturbed. This disturbance is called a non-linearity. During a test process to determine non-linearity of a touchscreen, Non-linearity values are calculated at many locations. Average value of these non-linearities is referred to as Average Non-Linearity.


Non-linearity (Maximum)

The non-linearity with highest absolute value, observed during linearity testing of a touchscreen, is referred to as Maximum Non-Linearity.


Privacy Filter

An optical filter which restricts viewing of a LCD display to the perpendicular direction


Reflection

Reflectance is defined as the percentage of the incident light that is reflected from the surface of a material. Reflectance typically is measured at a specific wavelength or a range of wavelengths.


Sheet Resistance or Resistivity

Sheet resistance is a measure of resistance of ITO coated film or glass. It is expressed in terms of Ohms/Square (Ω/▫).


SLRT

Sun Light Readable Touchscreen.


Switch Bounce

When a mechanical switch is activated the mass of the moving contact and the springiness of the material causes several additional contacts before it settles. For example when the switch is turning on a lamp or an electrical appliance the bounce is not an important factor. But when the signal from a switch is received by a digital system having a much faster response than the frequency of the bounce then it becomes an important issue and worthy of consideration.


Touchscreen Tail

Tails provide means of transferring electrical signal to and from a touchscreen to a touchscreen controller.