LED displays are used for almost any and every purpose in today’s digitised world. Just by looking at the world around it becomes evident just how far LED technology has come. LED displays are found in homes, on floors, ceilings, wrapped around columns, propped on glass and even covering the entire façade of large buildings. They have invisible LED displays, flexible LED displays, LED displays that could be combined like jigsaw puzzles to take on the exact shape and size of the installation surface and much more.
As LED technology advances the brightness of LED electronic displays have increased exponentially whilst their size has been getting smaller, slimmer, more flexible, versatile, robust and easily configurable. Nevertheless, the quality of LED displays has always been held as a priority and also continues to improve. This is among the primary reasons as to why LED displays have become a trend and have taken the entire world of digital displays by storm. According to LED solution providers such as Street Communication, LED video displays are used for both home and commercial purposes simply because they consume less energy, last longer and offer higher visual quality. The tech wizard who has been attached to Street Communication also asserts that the quality of LED displays cannot be attributed to just its dot pixel size (pixel pitch) as there are many other factors ranging from the types of LED lights used, the ICs, the display driver and scan modes. Given the fact that pixel sizes (which indicate the distance between the LEDs in millimetres); this article will pay special attention to the scan mode which also has a significant impact on the quality of LED displays.
The quality of LED displays is dependent on a variety of elements or rather specifications which range from perceived image performance, reliability, pixel pitch size, LED display flickering and many others which makes it hard to know the prices ratios of these specifications or how they are calculated users rummage through specification sheets or the user guides that manufacturers include in the product.
For instance, fine pitch/ narrow pixel pitch size has hit the market for nearly a decade and quality ratings are also afforded for the life cycle of LED displays that in the current times are upwards of 100,000 hours or about 11 years. Hence three primary elements are considered when seeking to choose LED displays as indicated by the spokesperson from Street Communication which is as follows:
Image Performance is the key factor and involves assessing the overall performance of LEDs. Consistency, stability, and reliability are gauged based on the fact that they are critical towards image performance and as well as the long life. The size of the LED also governs the pitch of the pixels, which is the determining factor for resolution and thus image quality.
The Drive Electronics that make up a big part of the entire system is only second to the LEDs themselves. This is because the circuitry plays a vital role in the reliability, power, and more importantly in this case – image fidelity.
The Mechanical Design which is primarily related to alignment and mounting depth is also a vital factor towards creating a seamless image projection. Ensuring that seams are aligned perfectly to not form black or white lines is also important as the human eye would discern these lines quickly which makes viewing uncomfortable.
Another often mentioned technical term is “scan mode”, otherwise also referred to as “driving method “which can be confusing to both end-users and technical personal. However according to the ‘tech commandos’ at Street Communication ‘scan mode’ is not hard to understand at all. A simple example that could be used to explain the scan mode for 1/4 driving led display could be imagined that at a given moment, that only 1/4 of the LEDs is being driven by the IC. Although this may be quite the challenge to discern with the naked eye, professional cameras set at high shutter speeds can capture it. Scan modes exist in ratios of 1/4, 1/8, 1/16 which is acceptable since most times we do not require high brightness or high refresh rate frequencies. This is also in line with the need to reduce the level of power consumption and hence the cost. The scan mode, therefore, can be stated as the element that determines the ratio of the number of lines of LEDs that are driven simultaneously to the total number of lines of each module. The scan mode of a LED wall screen can be an important parameter to choose between several tiles as it impacts three critical parameters of the LED screens which are the light perception, the electric consumption and the refresh rate which. When the refresh rates are higher it compensates for a low scan ratio. There are two primary modes of scanning which are static scanning and dynamic scan modes for video displays.
Dynamic Scan Mode
Dynamic scan mode involves the implementation of a ‘point to column control’ system for which a dynamic scan control circuit is needed. In general, the cost for dynamic scan modes are lower compared to static scan modes, but as can be expected offers a less effective video display brightness and higher loss from the output between the pixels.
Static Scan Mode
Static scan modes, on the other hand, involve the implementation of the output driver between the pixels “point” of control which does not require it to have a control circuit. However, the cost for static scan modes are significantly higher compared to dynamic scan modes and as can be expected the video display quality is good and stable apart from the fact that the loss in brightness and stability is significantly smaller.
The scan mode is a critical aspect or element for consideration based on the fact that it impacts the quality of the video display, LED display flickering rate, refresh rate and as well as the number of frames per second. The number of frames per second is in turn vital towards the ‘smoothness’ of image projections for LED video display systems.