What is Pixel Pitch in LED Video Wall?

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What is Pixel Pitch in LED Video Wall?

2020-02-12

Pixel pitch is an important characteristic to consider when deciding between options in an LED display or similar technology. This article will tell you everything you need to know about pixel pitch, particularly with regards to viewing distance.


Part 1. Pixel Pitch Basics



What is pixel pitch, what is a pixel pitch, and what is LED pixel pitch? 

These questions all have the same answer: pixel pitch is the linear measurement between the centers of each pixel on an LED display. Adjacent centers are measured in millimeters. 



What is pixel pitch sometimes called? 

Pixel pitch can be known by many other names, including dot pitch, line pitch, phosphor pitch, or stripe pitch. All terms refer to the same concept of spacing between a matrix of pixels.



What is pixel pitch vs pixel density? 

A common measurement of pixel density is pixels per inch (PPI), which describes how many pixels can be found in a linear or square inch of an LED device. 



What is a good pixel pitch? 

This depends on the requirements for your system. A smaller pixel pitch means that there is less space uncovered by pixels between adjacent pixels, and corresponds to a higher resolution; in contrast, a smaller pixels per inch value corresponds to lower resolution, as a lower PPI means a lower density of pixels. 





Part 2. How Does Pixel Pitch Affect LED Displays?


small-pixel-pitch.jpg


As discussed previously, a smaller pixel pitch​ corresponds to a higher resolution on an LED display. Smaller pixel pitch allows for crisper images and borders when a screen is viewed from a lesser distance; the smaller the pixel pitch, the shorter the minimum viewing distance can be achieved for a particular device. However, this improved performance comes with its own downside. Smaller pixel pitch can only be achieved by investing in a more expensive LED display board.





Part 3. How to Choose the Best Pixel Pitch?



There are 5 main factors to consider when choosing the proper pixel pitch for an LED video wall.



1. Board size. If you know the desired size for your LED board, you can backtrack from this measurement to an optimal pixel pitch. For a rectangular board with a shorter vertical dimension than horizontal dimension, a general rule of thumb to achieve a standard resolution of 1920 x 1080 is to divide your horizontal dimension (in feet) by 6.3 to get your pixel pitch (in mm). So for example, a 25.2 x 14.2 foot board is best served by a 4mm pixel pitch, as 25.2 / 6.3 = 4.



2. LED screen optimal viewing distance. If you know the desired viewing distance for your LED board - for example, the distance to a billboard from a highway - you can simply divide your desired viewing distance (in feet) by 8 to get your optimal pixel pitch (in mm). So for example, a 32 foot viewing distance would correspond to a 4mm pixel pitch, as 32 / 8 = 4.



3. Indoor or outdoor. Outdoor screens will generally be viewed from a larger average viewing distance, so you can use a larger pixel pitch for a more cost-effective option without sacrificing customer experience. By contrast, indoor screens will generally be viewed from across a hallway or lounge at the furthest, so a smaller pixel pitch is more important in these applications. 



4. LED screen resolution. As discussed previously, if you need a higher resolution, you will need a smaller pixel pitch. Similarly, if you are alright with a lower resolution, you can use a larger pixel pitch.



5. Your budget. It is important to consider what pixel pitch is optimal for your application given the resources that you have at hand. A superior pixel pitch that is outside of your price range is not a useful figure to know, so always consider your budget when choosing a pixel pitch.



In summary, the general rule of thumb is that a smaller pixel pitch will always result in a higher resolution and clearer image. However, it is only worth investing the higher capital required to procure this level of sophistication if the application merits such an investment. Usually, an application will be worth this investment if the screen will be viewed from a short distance, but not if the screen will usually be viewed from afar.





Part 4. Typical Pixel Pitch Measurement



This section describes some usual pixel pitch measurements for your reference. 



Indoor screens generally use LED displays with pixel pitches in the range of 4mm to 20mm. In a retail store or office environment, a 4mm pixel pitch is generally considered optimal, as most viewers will be quite close to their screens. Similarly, airport signage tends to use pixel pitches from 5mm to 6mm, as these relatively small screens can be viewed from up close by travelers. In shop windows, LED displays tend to have pixel pitches of closer to 11mm, as people will be viewing these signs from across the street or down the block. People who are close to the shop will then already have gotten the sign's message, so close-up resolution is less important here.



Outdoor screens generally use LED displays with pixel pitches in the range of 16mm to 25mm. What pixel pitch is good LED sign material? For smaller signs, 16mm is a good estimate. For smaller digital billboards, 16mm to 20mm is a good range, whereas larger digital billboards can get by with 25mm to 32mm. These pixel pitches are all larger than the indoor values discussed above, as they will rarely be viewed from close up. In these large applications, costs can add up so using a larger pixel pitch is a smart choice when considering the budget.





Part 5. Pixel Pitch & Visual Acuity Distance & Average Comfortable Viewing Distance Chart



The following values tell you a certain pixel pitch (in mm), as well as the corresponding visual acuity distance (in m) and the average comfortable viewing distance (in m).



0.75 / 2.58 / 1.29

1.00 / 3.44 / 1.72

1.25 / 4.30 / 2.15

1.50 / 5.16 / 2.58

1.75 / 6.02 / 3.01

2.00 / 6.88 / 3.44

2.24 / 7.74 / 3.87

2.50 / 8.60 / 4.30

2.75 / 9.45 / 4.73

3.00 / 10.31 / 5.16

4.00 / 13.75 / 6.88

5.00 / 17.19 / 8.60

6.00 / 20.63 / 10.31

7.00 / 24.07 / 12.03

8.00 / 27.50 / 13.75

9.00 / 30.94 / 15.47

10.00 / 34.38 / 17.19


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