ECR (Emitted Light Ratio)

With the advance of technology, display has become indispensable in our daily life. Have you ever counted how many times you use display? Have you noticed that display automatically adjusts its brightness when you move outdoors in sunlight? There is an amazing changing in displays’ luminosity in different situations. What is it?  Here's...

Sunlight is much stronger than fluorescent light used indoors. Thus, you will find that you cannot really read your screen clearly when moving outdoors with the same level of screen's brightness. In addition to the changing of light source(from sunlight to fluorescent light), screen readability can also be affected by screen's brightness and reflectivity. The three factors together can be called "ECR (Effective Contrast Ratio)". The higher ECR, the clearer we can see under the sun. ECR should at least reach 3 can your screen be read, and above 3, it guarantees a sharp sunlight readability

ECR = 1 + (Emitted Light / Reflected Light)
Emitted Light:  module’s brightness
Reflected Light:  Sunlight (10000 nits) × reflectivity


LCD Outdoor Readability


Unreadable under the sun.


Readable under the shady place ;
Can hardly read under the sun.


Fine readability.


Good readability.


Excellent readability..


Outstanding readability.

For example, an ordinary laptop is about 200 nits with 2% of reflectivity. Therefore, it's unreadable under the sun.
ECR = 1 + (200 / (10,000 x 0.02)) =1 + (200 / 200) =2

To overcome this situation, EVERVISON increases TFT backlight to 800 nits, which means ECR 5. So, it won't be a problem to read under the sun.
ECR = 1 + (800 / (10,000 x 0.02)) =1 + (800 / 200) =5


LinkThe video(start at 28 seconds) below demonstrates EVERVISION's Sunlight Readable Effect. In this experiment, sunlight has been replaced by LED light. You can see the screen on the left is unclear and the light is scattered by the strong light. However, with great ECR, the screen on the right is clear and sharp. The light does not be  scattered. The experiment shows a great difference. Sunlight Readable Effect plays a significant role in screen readability.

☛​ Link to Sunlight Readable Solution

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