For an LCD to be viewable outdoors in a bright environment, it needs to be high bright. LCD TVs used in your home are for indoor viewing. If you move it outside it will look washed out and images will be difficult to distinguish. Not what you want for digital signage displaying advertising or other public content.
How do we measure brightness in High Bright LCD Displays?
The unit cd/m2 (candelas per meter squared) measures brightness, also known as “nits”. Your TV at home will be somewhere between 300 and 400 nits. For a LCD to be clearly viewable in an outdoor environment, it needs to be between 1500 and 2000 nits depending on the size and positioning of the display. In the picture below you can clearly see the difference between a standard brightness and high bright LCD. On the left is a standard TV display (350nits), on the right is a Metrospec X47i display (2000nits).
Picture: (left) 350nit CHEMI LCD (right) 2000nit Metrospec X47i High Bright LCD outside in full sunlight.
The LCD on the left (350nits) looks to have terrible contrast because the sunlight defines the minimum black level, while conversely the high lumen output of Metrospec X47i on the right (2500nits) pushes the brightness of the highlights well above the minimum black level set by the sunlight reflecting off the display.
What about backlighting in High Bright LCD Displays?
An array of LED’s makes up the backlighting in a modern LCD display. LED’s are much more efficient than the ancient incandescent bulbs or compact fluorescent lamps (CFL’s) they replaced, but they are still not terribly efficient. Only about 3% of the electrical energy turns into light. The rest emits as heat.
Picture: The backlight inside a Metrospec X47i high bright LCD display.
Our high bright displays handle the higher power needed to project more light. There is almost a linear relationship between the brightness and power consumption. A 1500nit display is 4 times brighter than your TV at home, but it also uses 4 times as much electricity, much of which is heat.
To give you some feel for the magnitude of the numbers we are talking about here, the Metrospec X47i utilises a 214watt backlight to achieve a brightness of 2000nits. If we assume an LED efficiency of 3% (that is, 3% of the energy used is turned into photons of light) then approximately 207 watts of heat energy will be produced by the backlight set at full brightness.
If you are concerned about your power bill, don’t worry. An optional light sensor that automatically dims the display based on ambient light conditions, reduces energy consumption and running costs can be included with your display.
Hopefully, this has highlighted one of the key differences between a Metrospec display and others on the market.
If you have any questions about our products or services, please drop us a line. Our sales team would be happy to help.