It is known that white light is a mixture of colors, such as two-wavelength light (blue light + yellow light) or three-wavelength light (blue light + green light + red light), which can mix white light. Because the current development of white LEDs is based on Blu-ray technology, the following are the main ways that LEDs generate white light:
1.Use red, green and blue light-emitting diodes to adjust their individual brightness to achieve white light. Generally speaking, the brightness ratio of red, green and blue should be 3:6:1, or only red, green or blue. Two yellow LEDs adjust their individual brightness to emit white light. The biggest drawback of such a white light structure is its high cost, which is not conducive to commercialization.
2. To emit white light, blue InGaN LEDs can also be used to de-excite yellow phosphors. The structure of this white light is to put the blue LED and the YAG fluorescent substance together and use blue light to excite the fluorescent substance so that the spectrum it emits is white light. In this regard, Japanese LED manufacturer Nichia Chemical Co., Ltd. (Nichia Chemical Industry) has a global patent.
3. Use UV LED chip to excite RGB (red, green, blue) fluorescent powder to generate white light.
Based on the above three criteria, we can categorize the white LEDs as follows:
White LEDs can be classified into two types of wavelengths and three wavelengths. The two wavelength types are divided into two subclasses: single-chip (blue InGaN + YAG) (blue ZnSe + substrate) and dual-chip (blue InGaN + yellow-green chlorohydrate gap).
The three-wavelength type is divided into two types: single-chip (red, blue, green, and one-chip LEDs) (ultraviolet chips + red, blue, and green fluorescent bodies) and multi-chip (red, blue, and green LEDs, 3Chip), all of which can achieve LED The purpose of emitting white light.
