White light light-emitting diode

Abstract

The invention discloses a white light light-emitting diode which comprises a substrate, an ultraviolet light-emitting diode grain and a fluorescent powder layer, wherein the substrate comprises an anode and a cathode or a circuit; the ultraviolet light-emitting diode grain is arranged on the substrate, and emits ultraviolet with wavelength of 320-400nm; and the fluorescent powder layer is coated on the ultraviolet light-emitting diode grain, and is mixed by blue, yellow and red fluorescent powders and a transparent glue material, the blue fluorescent powder is excited by blue light with wavelength of 400-530nm, and the transparent glue material is permeated by visible light and ultraviolet.

Description

technical field [0001] The invention relates to a white light emitting diode, in particular to a white light emitting diode in which blue, yellow and red fluorescent powders are mixed in a fluorescent powder layer. Background technique [0002] At present, the light emitting diode (LED) in the light-emitting module used to emit white light on the market has the advantages of small size and can be used for lighting in array packaging. When using LEDs of different colors for different color combinations, Various colors other than white light can be emitted. [0003] The so-called "white light" usually refers to a multi-color mixed light. The white light seen by the human eye is formed by at least two or more wavelengths of colored light. For example: blue light plus yellow light can obtain two complementary wavelengths (complementary wavelength ) of white light, blue light, green light, and red light can be mixed to obtain three-wavelength white light. In daily life, no matt...

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Problems solved by technology

[0007] However, this kind of white light emitting diode made of blue light emitting diode chip and yellow light phosphor has at least the following disadvantages: 1. Since blue light accounts for most of the light spectrum, there will be high and uneven color temperature, so , it is necessary to increase the chance of the interaction between blue light and yellow light phosphor to reduce the intensity of blue light or increase the intensity of yellow light

2. Because the light-emitting wavelength of the blue light-emitting diode will change with the increase of temperature, which will cause the color drift of the white light source

3. Due to the weak intensity of the red part of the luminous spectrum, when the object is irradiated, it cannot completely appear red, resulting in poor color rendering.

The advantages of three-wavelength white light-emitting diodes are: no disadvantages of luminous uniformity, no color drift with temperature and high color rendering, but the disadvantage is that the luminous efficiency is not high

[0009] In U.S. Patent No. 6,685,852, it is proposed to use a light source with a wavelength of 315nm to 480nm to excite 7 kinds of phosphors with different emission spectra, and mix them into white light. Although the color rendering of white light can be as high as 95, at least 4 different colors should be used. phosphors to achieve this goal

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