Optical Touch is emerging technology that is rapidly starting to dominant the market. First developed in the 1970’s at Carroll touch (now part of Elo TouchSystems), optical touch offer many advantages over other touch technologies with many believing that, if it wasn’t for certain drawbacks, it would be the dominant touchscreen today.

In the past, there were problems with the relative high costs compared to competing technologies and the issue of performance in bright ambient light that would cause the optical touch screen to malfunction. Today, advancements in technology has solved this problem and there has been renewed interest in optical touch especially with certain devices such as the iphone .

Another huge advantage of optical touch screen against other touch screen technologies is the digital nature of the sensor output when compared to other touch systems that rely on analog signal processing to determine a touch position. The continuous and repetitive impact causes it to malfunction, have complex signal processing demands (which add to cost and power consumption), demonstrate reduced accuracy and precision compared to a digital system and have longer term system failure modes due to the operating environment.

Advancements in technology has seen new components and improve signal processing reducing system failure with key components such as LED's, photodiodes and CMOS chips considerably improving the performance and reducing costs.

The conventional optical-touch system uses an array of infrared (IR) light-emitting diodes (LEDs) on two adjacent bezel edges of a display, with photosensors placed on the two opposite bezel edges to analyze the system and determine a touch event. The LED and photosensor pairs create a grid of light beams across the display. An object (such as a finger or pen) that touches the screen interrupts the light beams, causing a measured decrease in light on the photosensors. The measured photosensor outputs can be used to locate a touch-point coordinate. Usually the controller scans through the array of photo sensors rather than measuring all of them simultaneously; thus this touch technology is sometimes called ‘scanning IR’.

In more advanced versions of the technology, each photosensor measures light from more than one LED, which allows the controller to compensate for light blockage caused by non moving debris.

New optical touch technology is being used in many new up-coming products such as mobile phones and media playing devices, cameras, kiosk displays, GPS or the recent Apple Mac Magic Mouse.

The Magic Mouse uses powerful laser tracking that’s far more sensitive and responsive than traditional optical tracking. The whole mouse is the button and no need for a mouse mat as the whole experience is done by touch alone.

New York University have developed a new approach to large multi-touch screens that can detect multiple fingers. Perceptive pixel has taken it one step further and has formed to commercialise the technology to take place in applications ranging from interactive whiteboards to touch-screen tables and digital walls, any of which can be simultaneously used by more than one person. As you would imagine, these advancements are causing companies to create endless possibilities for their use. What are you going to find yourself touching next?

Karen McGregor is a New Media Consultant at Artisan. If you wish to drop her a line, you can contact her here.

Reference: ‘An overview of optical – touch technologies’ by Ian Maxwell