High rendering LED white light is usually achieved by using blue chip + yellow phosphor + red phosphor. Leds with different color rendering indexes can be obtained by adjusting the ratio of yellow powder and red powder.

From the spectrum diagram, there are two peak wavelengths of blue light and green light, which indicates that the amount of blue light and green light is sufficient, while the amount of red light is insufficient. To improve the LED's color rendering index, the red component must be increased, that is, the red component must be increased.

There are two methods to improve the red component of LED. One is to increase the amount of red phosphor, but the efficiency of red phosphor is not high, so it is difficult to obtain double high LED products with high luminous efficiency and high color rendering index. The second is to add a red light chip in white light, which has a high luminous efficiency and can greatly improve the red light component. It is easier to obtain LED products with high luminous efficiency and color rendering.

1-Ra75 white light spectrum, 2- increased red light spectrum, 3- Red light spectrum
According to our experimental test, when red light is not added, the LED color rendering index is only 75, and when red light is added, the color rendering index is as high as 95.