Touch Screen, Touch Panel

If you own a smart phone, use the self checkout lane at retail stores, or make purchases at kiosks, then you are well aware of the benefits and popularity of touch screens. Touch screens have virtually no moving parts and are therefore very durable and appropriate for frequent use in unlimited applications. The interactive experience and interface flexibility of a touch screen combined with ease-of-use and extreme durability are just a few reasons why touch screens have become so popular. We are is a leading touch screen provider with core competency in the design, engineering, and manufacturing of touch screen assemblies to meet the most unique human-machine interface (HMI) requirements for our customers.

What is a Touch Screen?

A touch screen is a transparent switch that is placed over a visual display. The switch enables interaction through physical contact by detecting the presence and location of a touch. A touch screen is one of the easiest to use and most intuitive of all computer interfaces, a touch screen allows users to navigate a computer system by touching icons or links on the screen.

A touch screen consists of a conductive bottom layer of either glass or film and a conductive top film layer, separated by small, transparent spacer dots. A voltage is applied across the conductive surface. When pressure from a touch is applied to the top layer, it is deflected and makes contact with the bottom layer resulting in a voltage drop. This change is detected by the controller. By alternating the voltage signal between the top layer and the bottom layer, the X and Y coordinates of the user’s touch are computed. This permits the display to function as a control panel and allow human to machine interface.

Components of a Touch Screen

A touch screen typically has the following basic components:

• Touch sensor – A touch-responsive surface, typically a glass panel that is placed over a visual display monitor. The technologies vary slightly, but typically, the sensor registers change in electrical signal distortion to sense a touch event and location.
• Controller – An electronic device (PCB) is the interface between the sensor and the display.  The controller takes information from the touch screen and translates it into information a computer can understand.
• Software driver – A computer program that enables the computer operating system and the controller to communicate.

Types of Touch Screens 

 To achieve the desired human to machine interface, there are a number of different touch screen technologies available. We offer a variety of touch screen technologies, including:

Resistive Touch Screens(4-Wire & 5-Wire)

The Resistive Touch Screen is the preferred solution for low-cost applications. It consists of a conductive bottom layer of either glass or film and a conductive top film layer, separated by transparent spacer dots.  A voltage is applied to the conductive surface. When pressure is applied to the top layer, it is deflected and makes contact with the bottom layer resulting in a voltage change. This change is detected by the controller.

This technology is functional and economical for industries and applications such as food service, industrial controls, point-of-sale (POS), and handheld devices.

Resistive Touch Screen Features:

• Activation by finger, glove, or stylus
• High touch point resolution
• Low power requirements
• Value solution
• Reduced optical clarity

Surface Capacitive Touch Screens

Capacitive touch screens have an all-glass construction with greater than 9H surface hardness. A transparent conductive indium tin oxide (ITO) coating is distributed over both sides of the glass substrate. An electrode pattern is printed around the perimeter of the glass to generate an alternating current over the top conductive layer. The touch of a conductive probe draws the current to the specific point of contact. The controller then calculates the location of the touch.

Capacitive technology provides durability, reliability, and enhanced optical clarity. However, it is restricted to touch sensitivity by conductive materials such as a bare finger or capacitive stylus. Popular industry applications include casino gaming machines, industrial equipment, ATM machines and point-of-sale (POS) kiosks.

Common Features/Benefits of Touch Screens

Touch screens share these common features and benefits:

• Virtually infinite options for user interface design and flexibility compared to physical buttons/switches
• Easy to use interface
• Requires less space – integrated design eliminates the need for external keyboards and other components
• Sealing options can make touch screens highly resistant to environmental conditions
• Faster interface and convenience then keyboard or mouse

Touch Screen Design Considerations

When considering a touch screen application, use the following questions to help determine the right technology for you:

• Interface – What type of touch interface do you need, finger, gloved finger, both, or stylus?
• Options – Do you need touch buttons, drag and drop, or signature capture?
• Display Clarity – Is optical clarity a high consideration?
• Environmental - Will the touch screen be exposed to chemicals, liquids, or extreme weather conditions?
• Cost - What are your cost considerations?

Applications:

Below are just a few examples of touch screen applications:

• ATM machines
• Retail point-of-sale touch screen kiosks
• Satellite  navigation systems
• Medical monitors
• Industrial touch screen control panels
• Tablet computers
• Casino gaming machines