Interactive display technologies Yuri Trofimov Valery Posedko Vladimir Sivenkov Sergey Lishik Vitalii Tsvirko Alla Posedko Alexander Pautino Abstract — The current state of the art of interactive displays, the main principles of their operation, and their functional characteristics are reviewed. Special attention is given to interactive displays with contactless control; in particular, to photo-sensitive displays. A number of photo-sensitive display cell designs are considered, as well as the problems related to the production of such cells. The results of the authors’ research in this field are presented. Keywords — Interactive display, contactless control, photosensitive. 1 Introduction Human–machine interfaces are constantly being developed in order to improve the effectiveness of information inter- change, allowing, at the same time, the maximum possibility for interactive dialog. First of all, let us define more exactly what we under- stand by the word-combination “interactive display” (ID). The term “interactive” when referring to a display, implies the presence of additional devices for input and processing of information. However, the mere combination of such devices and a display cannot be called an ID, as we can see, for example, a conventional PC display. The term “interac- tive display” also implies the imitation of certain human senses. Thus, displays sensitive to the touch, sound, and light can rightfully be called interactive. 2 Results and discussion The first family of interactive displays capable of receiving tactile input is widely known as touch screens. These IDs combine information input and display functionality on the same surface. This allows a decrease in the overall dimen- sions and improves the ergonomics of the interactive system as a whole. Recent advances in microelectronics allow for the creation of digital high-resolution photosensors for video systems. The growing processing power of computers makes the application of speech and image-recognition technolo- gies possible. These innovations enable the creation of interactive systems that could be controlled using voice, hand gestures, eye viewpoints, and nose or eyelid move- ments. The physical principle of the sensor operation deter- mines the type of ID, its advantages and disadvantages, and its possible applications. In Fig. 1, the classification of ID sensor technologies proposed by the authors is presented. The current ID by the sensor type can be divided into three groups: tactile (touch screens), photo-sensitive, and audio- sensitive. The arrangement of the sensors in space can be dis- tributed or concentrated. The devices with distributed sen- sors are easier to implement from a technical point of view because the point of action on a given pixel is relatively straightforward to determine on the level of electronics. For the second class of devices, special potentially computation- ally intensive algorithms are needed to calculate the point of action based on the data from several sensors. The sensor systems of modern touch screens can be based on various physical principles: resistive, electrostatic, acoustic, infrared light, electromagnetic resonance, etc. The sensor detects just one or two of the parameters by touching action that allows the display to determine, for example, the coordinates of the contact point and/or the force (energy) of the action. In most cases, this is sufficient for effective inter- action with the software, input of the graphical symbols, and image editing. The modern sensor panels have a common ancestor, the George Hearst’s digitizer created in 1970, which uses the resistive principle to determine the coordinates of the contact point. Touch screens are currently widely used in many indus- trial applications, from game machines to production con- Revised version of a paper presented at the 14th International Symposium on Advanced Display Technologies (ADT ‘05) held in Crimea, Ukraine, October 10–14, 2005. The authors are with the Institute of Electronics at the National Academy of Sciences of Belarus, Minsk, Belarus; e-mail: senso@inel.bas-net.by. © Copyright 2006 Society for Information Display 1071-0922/06/1407-0621$1.00 FIGURE 1 — Classification of the sensor technologies used in interactive displays. Journal of the SID 14/7, 2006 621