Do you really understand the color quality of LEDs?

There are two ways to get white light mainstream now:


1, RGB three primary colors mixed to get white light


2. It generates white light by exciting a special phosphor coating by blue light emitted by a blue LED.


The three primary colors of white light are not elaborated. For the simple technology of blue LEDs to generate white light for phosphors, the blue chip converts the blue-emitting phosphor coating with a wavelength of 450-455 nm into a visible spectrum, but with the thickness of the coating. Increasingly, the resulting visible spectrum will gradually turn to yellow light, which is manifested as a color shift at wide angles. This problem basically exists for all white LEDs, and the amount of color drift depends on the LED phosphor quality and coating design.



The light from the LEDs seems to be in one direction, but in fact the color has a lot of quality problems at wide angles.


Here is a simple way to test the light quality of white LEDs:


Put a piece of white paper on top of the LED bead to see if there is a yellow separation on the wide angle edge.




Secondary optics


Secondary optical design, especially the lens scheme, is prone to color separation when doing special light patterns and small angles. The design principle of the secondary optical lens is as follows. The design is based on the primary optics of the LED, and the light emitted by the LED is designed to the appropriate position, but if the LED lamp bead is not a lamp with a good package. The original light emitted has a significant color deviation, so the problem is amplified in the secondary optics, resulting in more serious color drift. Is there a way to solve the original sin problem of correcting this LED?



The answer is yes, some special surface treatment techniques can be done on secondary optics to reduce the color separation of the LED spectral distribution. There are a variety of surface mixing techniques, from the simplest matte surface to the race surface to the complex surface treatment of the blending process, such as the RZ blending surface of Finnish LEDIL Optics.


Compared to the uncontrolled frosted surface technology of the optical path, this RZ color mixing surface treatment technology maximizes uniformity, controllable light path and high efficiency. What is the principle? Please see the illustration below:



This kind of special light mixing technology is difficult to design and grasp the surface texture. It is necessary to reprocess the original light of the LED after the TRI optical design, and to approach the quality of the original LED light, and to ensure two major points:


First, the optical application angle designed by the original TRI cannot be changed.


Second, there is a need to ensure high optical efficiency.


At present, the efficiency of the light mixing effect is guaranteed to be no more than 70%. This new patented hybrid technology works with an optical device with an efficiency of up to 90%.


After talking about the principles and features, what is the application direction of this mixed-light surface treatment technology? This problem is better. If there is no technology that actually uses value in this society, it is a waste of development resources. The main directions of use are probably several.

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