While liquid crystals were discovered in the late 1800's by Austrian botanist and chemist, Friedrich Reinitzer, but it took until the 1990's before LCD displays were perfected and could be manufactured economically in different sizes. LCD panel displays are available in a wide range of sizes from a few inches, up to over 15-inches, and have spurred the growth of touch screen in information kiosks and in industrial sydtem controls as human machine interfaces (HMI).
Since the early 1990's a number of companies have been designing and manufacturing touch screen HMIs. HMIs have settled on LCD panels with a diagonal size of 6, 8, 10, 12 and 15 inches. As the single most expensive component, the cost of the LCD panel dictates the cost of the end product.
In industrial control system applications in particular there are some very practical reasons for the popularity of screen based HMI:
Industrial control systems and HMI
- A picture is worth a thousand words. What better way to provide machine interaction then to provide a visually stimulating interaction medium such as a touchscreen HMI
- Machine operation needs to be unequivocal. The user needs very direct input on the action he is taking when activating a machine. Touch screen HMIs provide a direct visual link to the machine.
- Deploying keyboards and mice in industrial environments raises issues such as the risk of moisture and dust getting into the devices. Industrial hardened keyboards and mice are available but why bother when your can have a touch screen HMI.
- The alternative to using screen based HMIs involves mounting discrete information displays and activation devices such as panels meters, switches, thumbwheels and lights. This alternative involves significantly more labour, has less flexibility and is harder to change in the event that the design changes.
- The corollary to the previous point is that the cost of implementing powerful operator interfaces for machines has plummeted.
As a consumer technology, touch screens have really come into their own since the iPhone was released. Now touchscreens are rapidly entering the main stream with the avalanche of touch screen operated phones following the iPhone, and the release of touch monitors for PCs.
Multi-touch displaysThe iPhone introduced another innovation in the form of the multi-touch display. Multitouch capability enabled features such as the iPhone's ability to zoom into an area on the screen by moving two finger tips placed on the touch screen in opposing directions.
PC operating systems are rushing to support this new found interest in touch and its capabilities with Windows 7 having gesture input, which means it supports a range of different movements to give input to a PC via a touch screen.
The future for touch screen displays the future is bright indeed. The following link is from a TED presentation given by Jefferson Han showcasing his work on touch driven displays. It is worth noting that this presented in 2005, so be suitably impressed: TED Presentation