Sharp's LCD Offerings
Continuing progress in LCD production technology permits the ever more efficient manufacture of larger and larger displays with diagonal screen sizes of up to 2.75 metres. This results in liquid crystal display screens presenting ever greater competition for posters, mechanical information panels and poster pillars. Advances like this will see the volume of the European digital signage market increase by a factor of five by 2011.
The electronic poster is now a reality. Sharp has already presented the world’s largest liquid crystal display, with a diagonal screen size of 2.75 metres (108"), and LCDs have now overtaken the dimensional range of current citylight posters. The advantage of digital signage displays is clear to see: unlike the static poster, the content of the image in the digital signage display can be modified – even on hundreds of screens at the same time if necessary – at the press of a button or completely automatically. At the same time, electronic panels can be subdivided into individual segments containing a variety of dynamic and static content. The operators of shopping centres, hotels, airports, museums, office buildings, etc, will have thousands of opportunities at their fingertips for displaying information, exactly as required for the specific situation. Touchscreen technologies lend a further dimension to electronic posters: interactivity. Instead of simply reading information, the user can react directly to specific content and call up additional information through the system.
Unlike the traditional poster or electro-mechanical display systems, electronic displays offer the advantage of containing no mechanical moving parts. With LCDs, the durability of the backlight normally determines the service life of the display. In the e-Signage sector above all, the crucial factor is that the displays must operate for a long time without any malfunction, especially in cases where access for maintenance is problematic. Accordingly, e-Signage panels and monitors from Sharp are designed to deliver a continuous operating performance of up to 50,000 hours. This represents just under six years of uninterrupted operation of the display, seven days a week, 24 hours a day. With the new 108" monitors, the background lighting unit is also easy to replace, thus considerably extending the overall service life of the system.
Periods of continuous operation of this nature impose additional demands on electronic display systems, particularly when there is static image content such as logos or headings on display over extended periods of time. Once the image is changed, there must be no residual shadow images left behind. Unlike active screen display technologies such as plasma, where images shown over an extended period can result in irreversible burn-in effects, no lasting retention effects occur in the case of passive liquid-crystal technology.
However, deployment in public areas, especially outdoors, imposes specific requirements on these displays. On the one hand, there is the requirement for a high-quality image similar to that provided by modern liquid-crystal televisions. On the other hand, the severe stresses known from the field of industrial applications must also be taken into account. Sharp has developed various technologies to optimise LCDs for e-signage applications.
For high picture quality, a high contrast ratio is more important than brightness. A wide all-round viewing angle is also essential to make the display easy to read from all directions. To bring these qualities to an e-Signage display, Sharp relies on the Advanced Super View (ASV) technology that it developed for TV panels. These LC panels achieve an extremely high static contrast ratio of up to 2000:1. Furthermore, ASV displays do not impose any specific viewing direction, offering a viewing angle of 176° and more. It is this ‘all-round viewing’ that lends LC modules the necessary flexibility in terms of mounting and orientation – horizontal or vertical – as well as in height, e.g. as an information display installed just below the ceiling of a room or at knee height.
With large-format standard LCDs, it must also be taken into account that installing modules vertically frequently results in reduced service life of the backlight system. This disadvantage becomes clearly noticeable, especially with diagonal screen sizes above 55". To counter this, for panels and monitors with 65" screen diagonals, Sharp has developed versions with a background lighting unit specially designed for vertical mounting, thus guaranteeing the normal extended service life.
Anyone looking to call the attention of passers-by to their products has only fractions of a second to do so. High-quality image reproduction has a crucial contribution to make here, in terms of determining whether the information in the image impinges on the consciousness of the casual observer – after all, what is the point of presenting glossy photos on large-scale displays if these are incapable of reproducing the original brilliance? The trend is now towards full HD resolution for e-Signage applications too, so that when viewed close-up on large-area displays, images do not appear rough around the edges, but with crystal clarity. Close-up viewing is unavoidable, especially when the application includes touchscreen functionality, e.g. with interactive POS systems. The images presented by a conventional PAL or NTSC system start to show the individual pixels in this situation, if not before.
Like no other flat-screen technology, LCD offers great variety in terms of screen size, optimum picture quality and readability for every area of application. At the same time, new technologies are creating new perspectives: for example, with the use of the Sharp-developed parallax barrier, it is now possible to display two (Dual Direc-tional Viewing) or three (Triple Directional Viewing) different images on a single screen, depending on the viewing angle. This is of specific interest for visitor guidance systems and advertising displays in the retail sector, as depending on the direction they are moving in, visitors and customers are presented with different information, such as special offers when entering a shop and bus departure times when leaving.