Touch monitors simplify the interaction between man and machine. The elimination of keyboard and mouse makes touchscreens popular wherever information can be clearly displayed on the monitor and the same monitor enables user-friendly operation.

Over time, several touchscreen technologies have been developed. In recent years, capacitive touchscreens have become increasingly dominant. We all interact with this technology daily: when using our smartphones. In commercial and industrial applications as well, capacitive touchscreens are displacing resistive ones to just a few niche areas. That is why we only offer capacitive touchscreens.

Selection Criteria

Professionally used touchscreens are expected to be robust, durable, long-lasting and highly reliable. Therefore, when selecting a touchscreen, consider:

• the appropriate IP protection rating against dust and moisture,
• the operating temperature range specifications, and
• the tolerance to shock and vibration.

Technical aspects:

• Screen size and resolution
• Mounting options (wall, stand, swing arm mounting)
• Response time
• Touch point accuracy
• Brightness and contrast ratio for readability in various environments

Certifications and standards:

• Industry standards (CE, FCC, RoHS, ...)
• Special certifications for industries such as food and beverage
• Medical specifications: including DICOM specification for grayscale behavior (contrast in black-and-white displays of medical imaging systems adapted to ambient light conditions).

Highlights

History and Technology

Optical Touchscreens

Resistive touchscreens are pressure sensors. When touching the screen, two superimposed, voltage-carrying but invisible layers are brought into contact with each other. At the contact point, the electrical resistance collapses. The location of the contact point is determined using the "voltage divider rule" known from circuit electronics.

Although resistive touchscreens are quite robust and somewhat less expensive, their market share has declined significantly. The lower image quality, limited multi-touch operation, slower response and lower touch point accuracy may have contributed to resistive touchscreens being largely displaced by capacitive touchscreens.

Capacitive touchscreens have a transparent metal oxide layer. An AC voltage source is applied to its corners, and when touched, a tiny current flows away through the finger. In simplified terms, one can imagine that the draining current had been stored "capacitively" in a capacitor. The current intensity of the draining current depends on the distance of the touch point from the four corners of the screen. The location of the touched point is derived from the four current measurements.

Some advantages of capacitive touchscreens:

• Operation with bare fingers or conductive styluses
• Simultaneous touch detection (multi-touch), gesture recognition
• Virtually wear-free glass surface
• Very good image quality, high contrast
• High touch point accuracy
• Fast response
• Improved robustness against external influences such as dust, moisture and mechanical stress.