Vivid colours and a wide gamut of them is one of the challenges that comes up for almost all display technologies and techniques present on today’s market. As manufactures are trying to combat the challenge and provide their clients with the best effects, they seem to be using the same methods to do so, even if their technologies are very different. The challenge here is not to create colours that haven’t existed before – manufacturers are simply trying to achieve primary RGB colours that are more pure and less diluted by colours that are away from the pure colours at the extremes of the colour triangles. How do they do that? Did anyone succeed?
How LCD faces the colour challenge
For years, manufacturers have been going with the simple solution of using separate LEDs for red, green and blue, but once they realised it can also cause a lot of problems, the started looking into different solutions. Right now, some companies use blue LEDs and quantum dots for the other two colours, which is much more expensive, but also much better quality.
There have been companies that have tried to improve their colour gamut by illuminating their LCDs by white LEDs using yellow YAG phosphors. However, there is still problem with the yellow, which often results in impure colours. One way to solve that would be to filter the light and take out all the frequencies between red and green. Another one would be to change the phosphors used to individual red and green rather than yellow, which happens to be effective, but expensive. So how are projectors dealing with that?
The fact that laser projectors can create the widest colour gamuts is no surprise to anyone at that moment. Lasers provide pure light in terms of frequency, but they are expensive and sometimes very difficult to develop with good efficiency. What did most projector manufacturers do? They followed a similar approach to the one used in LCD backlights and used phosphor to convert blue light to yellow and that is how most laser phosphor projectors work – with a blue laser and a yellow phosphor wheel.
NEC LP projectors took a different approach. They used a RB laser system and rely on phosphor to convert blue for the green, which in turn means that a relatively pure green can be created without the challenges of having to use a green laser or converting it from yellow. It seems that for now they have solved the problem pretty well.