What is the difference between RGB and white LED?

RGB color in power

When it comes to the grievances and grudges of white LEDs, we cannot fail to mention RGB and white LEDs. Both of them have the same goal. They all hope to achieve the effect of white light, but one is directly presented in white light, and the other is in red, green and blue. Mixed light. The purity of one party is not enough, the price is too expensive, and the color of the other party is beautiful. I am afraid that such a war will not stop in the short term.

However, although the greens and radishes have their own advantages, it is not so simple in terms of technology and cost. Some things cannot be compromised, because regardless of the consistency of frequency or voltage, if you can’t adjust , Then the mixed light may not be controllable at all. Therefore, both of these technologies are made by people and each has its own market. However, whether the market can determine the technology or whether the technology leads the market, I am afraid it will cause considerable discussion.

Those who like high picture quality should not be difficult to find that the colors of some LED backlight panels are particularly clear and vivid, even to the extent of high-definition TVs. This situation is the characteristic of RGB, which advertises red as red and green. It is the characteristics of green and blue that are blue. In the mixed color of light, it has more diversified characteristics, just like a painter’s palette, which perfectly presents the most real color world and makes a beautiful life.

RGB is obviously more diverse than white LEDs in applications. For example, when a certain band of light is needed, such as car lights, traffic lights, shop windows, etc., RGB can mix colors as you want. In contrast, white LEDs suffer. , So the effect is relatively unsatisfactory.

However, what is the principle of RGB light imaging? According to Cai Zhengda from the Institute of Electronics and
Optoelectronics of the Industrial Technology Research Institute, RGB lamps are integrated with the three primary colors.
In addition, there are blue LEDs with yellow phosphors, and UV LEDs with RGB phosphors. Generally speaking, these two have their imaging principles. , But the attenuation problem and the impact of ultraviolet rays on the human body are both difficult to solve in the short term. Therefore, although both can meet the requirements of white light, they have different results.

White LED reflects cost

Although white LEDs based on phosphors cannot resist the problem of color decay, they can gain a foothold in the market. The most important issue is actually the cost!

One shot beats three shots. This is the main reason for the market. Senior LED industry expert Steve Edwards, a professor at Oxford University, said that at the current cost, RGB lights are significantly higher than white LED lights, the only competitive place. Only on the backlight board, it is possible to compete with white LED lights in the future. As for other places, auxiliary lighting is currently used. As for RGB lights, there is a main problem, which is the reaction time. At present, most of the reactions of RGB lights The time is about 4-8ms. He said that if one day to go to a hypermarket, the reaction time of all RGB lights can reach 1-2ms, then the era of RGB lights is coming.

However, Steve also said that if the color mixing technology is not proficient, it will be a failure. After in-depth analysis, he pointed out that the adjustment of color temperature is often the most difficult part. When the color temperature is high, the overall tone will be biased. For cool colors, when the color temperature is low, the entire tone is warmer, so the color mixing technique must be quite good, otherwise it will cause considerable problems.

Why is there such a problem? The main problem lies in the frequency and wavelength of the three colors. Red light has the lowest frequency and the longest wavelength, which can reach 611nm, followed by green light, which has a wavelength of 544nm. Blue light has the shortest wavelength, which is only 440nm. Packaging the three RGB dies together will naturally cause problems.

Therefore, Professor Edwards said that when the RGB is separated, it can be controlled separately. Although it can be directly controlled and the color mixing is good, it is a big problem to achieve the white light that is mixed. Although it is expensive, the quality is relatively good. As for white light As far as LED lamps are concerned, although they are cheap to manufacture and can directly replace CCFL and become the main technology of LEDs, relatively speaking, they are packaged together because of the wavelength and frequency issues, so the scattering situation will be unstable.

However, the control problems of RGB lights still need to be strengthened. For example, if one of the lights is broken, it will be quite obvious on the entire screen. On the contrary, the white LED lights can complement each other because of the side-shooting relationship. It can make up for a broken LED, and make up for the uniformity, so that the overall situation does not look too bad.

RGB or CMYK?

Now that there are three colors, some people may think that some art publications use CMYK as the basic color. After such color mixing, can it also be applied to white LEDs? Professor Edwards said that for the existing RGB, the wavelength in the overall spectrum is the most primitive phenomenon. As for the concept of CMYK, it is different from the RGB method, mainly in that the backlight is mainly reflected light, and RGB can do it. As for CMYK, even if the saturation is high in the general imaging principle, the chromaticity is equivalent to the conversion coordinates of RGB, and the color may not be an ideal state. As far as he knows, it has not been heard in the market. There is such a way. 
If you want to solve the problem of RGB due to frequency mixing, Professor Edwards said that currently there are color filters in the market for integration after filtering, mainly based on the principle of RGB, or even RGB plus black. This is mainly because the RGB three-color reaction time is long or short. In the future, if the RGB three-color reaction time can reach the ideal state of 1-2ms, it should be able to meet the cost requirements more because there is no need to use color filters. To filter, the colors can be mixed accurately. At present, color filters are mainly controlled in the United States, Japan and other countries, so technological advancement helps to break the monopoly of filters in these countries.

In addition, he also said that there are also many specialty stores in the market, which sell different light sets according to the color needs of each family, whether it is toning or filtering, this effect adds more flexibility after customization. , It can also make the lamps and lanterns for life lighting more colorful, and can stimulate the market to make various conversions and demands.

Market or technology-led?

In the current situation of a hundred schools of thought, whether RGB technology will become the mainstream or white LED will become the mainstream, in fact, there is no definite answer. From the point of view of various parties, market application and cost will be the main key to determine.

Professor Edwards made it clear that in addition to the unsolved reaction time problem of RGB lamps, the high price is one of the main reasons. Therefore, even if two years later, it can rise and compete with white LEDs in the backlight market, but the expensive price is still It is fatal. Therefore, in the layout of the lighting business, white LEDs will still be the main source of lighting, while RGB lamps are mainly auxiliary lighting.