Anybody who have used a computer or watched a video would have heard the term ‘refresh rate’ and most would have ignored it from the ‘get-go’. However the refresh rate is a critical factor when it comes to video displays, especially LED video displays as it involves the number of times that a display updates its images every second. A simple example of refresh rates can be explained by taking a 60 Hz refresh rate monitor or video display and know that the display updates the images on the screen 60 times each second. This article is all about refresh rates and will get technical at some parts, but not to worry, the article explains technical aspects of refresh rates in the layman’s format.
If we look back to about two decades ago changing or tweaking refresh rates on CRT monitors was an element of optimising the monitor’s video smoothness. In essence a low refresh rate would cause the video display on the CRT monitor to flicker which could at times be picked up by the naked eye. Setting higher refresh rates would effectively eliminate flickering or reduce the level of flicker. Modern day LED video displays or even flat panel LCD monitors are by default loaded with higher refresh rates and the flicker is so minimal that viewers would not be able to pick-up the flicker. According to the technical geeks at Street Communication who are among the top LED display industry leaders a higher level of refresh rate will result in much smoother pictures.
It is due to this that high-end LED monitors that are primarily designed for gaming tend to advertise high refresh rates as part of their marketing strategy that range anywhere from 144 Hz to 240 Hz. These refresh rates are high and considered to be a significant leap from the previous 60 Hz or 75 Hz refresh rates of previous years. The maximum refresh rate that a video display is able to muster largely depends on the monitor type. According to the spokesperson from Street Communication cheaper monitors in general support lower refresh rates compared to expensive monitors and this holds true even for LED displays. To explain this in simpler terms, the refresh rates for even LED displays have a significant impact on ‘frames per second’ and the amount of LED display flicker. This in turn, has an impact on the quality of the images that appear on screen.
When considering LED displays, bear in mind that a higher refresh rate is generally a better option. However, it is not the only criterion that matters as there are other important elements that should be taken into considerations which include colour accuracy, response time and even viewing angles. Nevertheless, the highest refresh rate that a video display supports is a critical element towards the level of LED display flicker and the number of frames per second the display delivers. In some instances, manufacturers include ‘choice of refresh rates’ that monitors support and most modern computers select the best or highest refresh rate by default, but not always. Hence, based on the fact that users may sometimes have to set refresh rate manually, it would be to their benefit to know more about refresh rates and what it is all about especially with regards to LED displays.
Refresh rate of LED displays in the simplest terms refer to the frequency at which the LED display’s hardware draws data from its source. This frequency provides a measure of frame rate per second; however it is important to know the difference between refresh rate and frame rate per second. While refresh rates include the drawing of identical frames every second, frame rate specifically measures the frequency at which an entire frame of new data is fed into a display.
Movie projectors move frame to frame 24 times every second, however each frame is irradiated a couple of times prior to the next frame being projected via a shutter located in front of its light source. Hence, although the movie projector runs only 24 frames per second, the refresh rate is dependent upon how often each frame is illuminated by the light source, for instance if each frame is illuminated by the light source 2x before moving on to the next frame, then the refresh rate would technically be 48 Hz and if each frame is illuminated 3 x before the next frame is projected it would have a 72 Hz refresh rate.
Most new LED display screens come with a default refresh rate of about 400 Hz at minimum, however at this frequency, video cameras are still able to capture flicker. In order to overcome this challenge or in order to capture flicker-free images on cameras refresh rates should be well over 1000 Hz. According to Street Communication, modern high –end LED displays come with refresh rates that are as high as 9000 Hz which are quite easy to achieve. Although high refresh rate frequencies may be deemed as a good factor, it must be taken into account that high refresh rates require highly competent LED screen processors such as high-end driving IC MBI5252 & MBI5153. This is based on the fact that they have to spend more time in order to draw the frame and project it onto the screen which allows the overall brightness to be decreased.
To make a long story short the higher the refresh rate, the more images will the LED display be able to project each second. Hence, it is a fact that regular refresh rates will cause 3rd party recordings to capture flicker on other imaging devices. A point that must not be forgotten is that the refresh rate is not the only factor that makes LEDs good or bad, as other elements such as software, display control, configurations and display hardware are also very important towards the quality of the overall output.