Led Display Technology
A partnership to your advantage. With their 20 years of experience in the manufacturing of LED displays, Voglhuber GmbH with its seat in Petzenkirchen, Lower Austria, is a highly competent partner for us.
Voglhuber GmbH & Co KG
Fritz Sedlazek Platz 3
Tel: +43-7416-538 43-11 DW
Fax: +43-7416-538 43-44 DW
so-logic GmBH headed by DI Peter Thorwartl has, with its many years of experience in the area of digital control technology, brought valuable expertise into the team. Mister Thorwartl acquired his skills during his work as research assistant at the Vienna University of Technology. There, he worked in the special field of "Programmable Logic Devices (FPGAs)" at the Institute for General Electrics and Electronics.
so-logic GmbH Co KEG
DI Peter Thorwartl
A-1090 Vienna, Austria/Europe
Phone: +43-1-315 77 77-11
FAX: +43-1-315 77 77-44
GSM: +43-664-4 160 188
GSM-FAX: +43-664-4 187 593
Cooperation with us grants you the following advantages:
- State of the art technology from one source
- Development and production in Austria
- Enhanced quality through innovative technology
- Price advantage through direct sale
The technological possibilities offered by digital driving as well as the fibre-optics data distribution solution we developed, have enabled us to implement a variety of new features. Below, you will find explanations of the essential charateristics of our LED displays:
The video wall is driven directly by the VGA graphic card of any Pentium PC. All data that can be represented on a PC screen (formats: 640 x 480 VGA to 1600 x 1200 pixel) are directly transmitted from the PC VGA graphic card to the LED display over a fibre optics cable. The image data are represented on the LED display in real time (text, picture, sound, video, animation, ...) with simultaneous display of up to 16.7 million colors (with RGB). The distance between the display and the source (PC, video, camera) can be up to several kilometers! The display functions like a monitor with high brightness level for outdoor use. Flexibility and image quality of your presentation depend on the resolution.
EMC - Electromagnetic Compatibility
Most manufacturers of LED displays use copper (flat band cables) for the internal cabling of their systems (modules or LED pixel arrays). This can lead to interference radiation, which may have a perturbing effect on radio circuits, on other electronic devices or on the application itself. In our videowall we use only all-plastic or glass fibres and can thus largely prevent interference. Systems featuring fibre optics technology are 100% floating units.
You need not purchase special software for the control of the display - any multimedia graphics software available on the market will do! For the video transmission in real time and real colors PC video cards in combination with professional front-end video systems can be used for driving (scaling, converting) the display. Thus, the videowall can take the function of a large screen television display and is perfectly suited for outdoor use in full daylight and at high insolation.
The fact that the software can be freely chosen enables a variety of possibilities for the application of the LED display. Possibilities for driving the LED display:
- via internet
- online via a PC direclty connected to the display
- offline via telephone line and modem
We shall be pleased to advise you on which possibility is best suited for your needs.
For two years we have been broadcasting advertisements and the most recent traffic news in collaboration with Austria's leading automobile association, the ÖAMTC, on an LED display located on Vienna's city expressway A23. The information displayed comes directly from a PC in the traffic information office of the ÖAMTC in Vienna. The BTV bank in Innsbruck, Tyrol, has charged us with the installation of a 10 x 1 m LED display on a site fence. On this display (monochrome, red), the radio station "Antenne Tirol" broadcasts breaking news from the Austrian Press Agency 5 times a day via dial up lines and modem.
- Mediamarkt in Linz
Many scoreboards, also by other manufacturers, use our fibre optics controller, for which we won the Innovation Award of the provincial government of Lower Austria several years ago.
50 Hz, 60 Hz Refresh Rate
A good television set builds up a picture at 2x50 Hz, i.e. a total of 100 Hz, which produces a picture that appears nearly flicker-free to the human eye. The eye is extremely sensitive to flicker in large area LED displays. Therefore, it is necessary in to work with an even higher repetition frequency in order to avoid the so-called large area flicker. Our videowalls are able to recognize 50 Hz as well as 60 Hz signal sources and switch automatically between the two frequencies, so that no additional external conversion is needed. On our videowalls, the image is displayed at 800 or 960 Hz respectively, a frequency that grants a flicker-free picture!
Customary LED displays can represent colors only in a linear sequence. Our fiber optics technology and controller programming with the use of Xilinx FPGAs have enabled us to adapt the color sequence on the display to that of the human eye (curve according to Weber-Fechner Law) and to achieve a color representation that is as close to the natural colors as possible.
Due to improved power supply design, the power consumption of the videowalls produced by us in Austria could be reduced by 1/3 in relation to other comparable LED displays, which results in considerably lower running costs.
The luminosity of LED displays is especially important in outdoor use. It is usually expressed in cd/m2 (candela [cd] per m2). The ambient luminosity out doors amounts to between 800 and 1200 cd/ m2 depending on location and weather conditions (rainy, cloudy, direct insolation). If the brightness level of the display is not higher than the ambient light level, the display is not readable.
In the area of light sensors, there are also considerable differences: most sensors are automatically provided with 16-step brightness adaptor, just like the dimmer switch in your living room. The light sensor in our video walls is computer-controlled and provided with a programmable logic. Daylight is permanently changing, also under steady weather conditions. Our sensor does not only measure the ambient light level but simultaneously also the color temperature. By sensor programmation with Xilinx and by real time driving of the LED in (over fiber optic cables), the optimum LED emission and respective luminosity can be calculated any time. Thus, the display performance can be constantly optimized according to the present light conditions.
Color / gray
Color /gray shade depending on the respective color, the LED we use can represent up to 256 color shades per color (RED, for example). In the full color (RGB) mode (Red Green Blue) this amounts to a total of 16.7 million colors.
Full graphics display
Display of animated pictures, videos, texts, etc. in real time over the entire display area in picture and photo quality.
Videowalls are produced in pixel sizes of 10, 15, 20 and 30 mm. Depending on the intended viewing distance and on the location of the appliance, pitch (pixel size) is an essential criterion for choosing the best suited LED display. The decision which spacing is to be preferred, is influenced by various location-related factors and the individual application (e.g. traffic guidance, advertisement, stadium display, video transmission).
Pixel size ideal viewing distance
- 10 mm 10 - 40 m
- 15 mm 15 - 80 m
- 20 mm 20 - 120 m
- 30 mm 30 - 200 m
The pitch is the space between two pixels measured from the center of one pixel to the center of the adjacent pixel. It is always expressed in mm and depends on the type of LED - different manufacturers offer different types, and there can be considerable differences. For our LED displays we exclusively use preselected LED by renowned manufacturers, as for example Nichia or HP.
The location of the display depends on the specific application and plays an important role in the decision as to which is the ideal emission angle.
Single pixels in multi-color displays (RGB or RG) consist of several LED so that the necessary luminosity and and the desired range of colors can be produced. By installing the LED in different angles, we are further optimizing brightness, emission angle - or viewing angle often given in specifications and varying greatly according to subjective perceptions - and off-axis viewability. Virtual pixel The special control logic makes the eye perceive a higher pixel resolution than is actually physically existent, which means top quality at a distinctly lower price.
For a full-color RGB display (16.7 million colors) we only use a total of 3 LED per pixel. By programming single pixle arrays with Xilinx we can produce a brightness level of = 4.800 cd/m2 . Similar LED displays which do not feature a programming option comparable to Xilinx need much more LED per pixel in order to achieve the same brightness level, which results in higher weight, power consumption and price. (e.g. 5 instead of 3 LED/pixel - specifications for LED RGB displays with 15mm pitch spacing.
The modular construction of the displays enables you to combine the single modules however you like (vertically, horizontally) and to create the display size that you need. All modules, irrespective of the pixel size (10, 15, 20, 30mm), can be supplied in units of 24 x 24cm (size of pixel array), which makes it possible to build any display format with an accuracy of 24cm.
Modular architecture and pixel correction allow you to expand your LED display with additional modules or to repair single modules without lessening the original homogeneous image quality.
The half-life period of our top quality pre-selected LED is about 100.000 hours. This does, however, also imply that after 10 years of constant full power operation the brightness of the LED is reduced by appr. 50% (see also: "LED Life"). We do not know of any manufacturer that produces LED with a longer half-life period.
LED which have been in operation for a longer time, consequently are not as luminous as those just produced (compare: "Durability"). Should you want to enlarge your existing LED display or exchange part of the LED for new ones, then this will result in different levels of brightness in the various pixel arrays or modules. In our videowalls this problem can be compensated by means of a special software module. So, we can guarantee a homogeneous image also in displays enlarged with additional modules. Such a pixel correction can be carried out any time in the course of our maintenance services. Half-life period, by the way, is a phenomenon that affects all LED, regardless of manufacturer or type.
Our special soldering technique, which is protected by utility patent in the production and assembly of pixel arrays enables particularly gentle handling of the LED. It also allows for longer-lived and "cleaner" solder joints. These advantages result in a further prolongation of the appliance's life-period.
Balancing of the 3 primary colors (R, G , B) used in a multicolor display together producing the color WHITE. All our displays are capable of producing white balance. They are calibrated in the factory and can be corrected after activation.
Please note the difference between emission angle and viewing angle as explained below. Emission angle: Our data sheets give both the emission angle (technical specification by manufacturer) and the often quoted viewing angle. A horizontal (emission) angle of 120° for instance indicates that maximum brightness is reduced by half if the viewer moves sideways by 60° from directly facing the lit LED display. Viewing angle: is the angle at which half of the image can still be recognized by a person looking at the LED from the side.(This measurement always reflects an individual perception and is not a manufacturer specification based on the outcomes of sophisticated measurement procedures testing brightness and readability.
Color Purity and Luminance
We are priding ourselves on guaranteeing a color luminance of at least 70%. This advantage becomes fully apparent when only one color is displayed on the screen: our displays are showing far fewer blurs than other, similar displays.
Feedback, telemaintenance, current measurement and virtual pixels have been provided for in the development of the module hardware and can be supplied immediately for an extra charge. We can check the function of every single LED and the temperatures in the module and feed back the information to any PC regardless of how distant it may be (essential in traffic appliances). The feedback ensures the reliable check of the "correct", i.e. the intended content and enables possibly necessary corrections.
When comparing different manufacturer's data sheets, it is important to make sure whether the emission angle or the viewing angle is given, whether the system features pixel correction and/or any other means of color or brightness correction (dimmer, pixel correction, white balance), and to find out which technology is employed and, above all, how it is implemented. Then, you should also make sure that the luminosity is given in comparable units, such as cd/m² (candela per m²), so that you can easily evaluate different products. If you want to be absolutely sure, just ask if, when, by whom and how luminosity has been measured and if you could have a look at the test certificate.
Your trust means a lot to us.
Only when comparing standardised, objective evalution criteria you can safely say which are the differences between the displays offered by the various manufacturers, and only then can you evaluate quality and price from a technical viewpoint. Should you require any further information, do not hesitate to contact us!