High power white LED application technology to explore in the field of lighting

For type power white LED light source, high luminous efficiency, single light flux, reliability, high color rendering and cost determines its competitiveness in the lighting market. How can was prepared with high luminous efficiency, high color rendering of white LED, LED can be widely used in general lighting is a premise, the preparation of white LED current can be divided into three types: red, green, blue, RGB） Combined wafer white light, white light, blue chips with fluorescent powder synthesis MOCVA directly grows more white light of the active region.

several kinds of technology, by contrast, in addition to being at the exploratory stage study of MOVCA direct growth more source area of white LED technology. Although RGB LED has high luminous efficiency, as well as good color rendering, but is different, the performance of three kinds of chip makes them because of the drive current or temperature drift, and the influence of such factors as color stability. In blue chips with fluorescent powder synthesis white LED application in the field of lighting, how to improve the luminous efficiency and color rendering index is the focus of the discussion in this paper.

a, to enhance the efficiency of light-emitting phosphors with selection and preparation is the key

is luminous efficiency of light energy conversion into visual ability. General power type white LED luminous efficiency of the main ways are as follows: 1 > to improve the luminous efficiency of the chip. 2 > the wafer light effectively extracted. 3 > will be extracted efficiently export LED light tube in vitro. 4 > LED to low thermal resistance. 5 > improve the excitation efficiency of phosphors. After a great deal of experiments proved that the choice of phosphor powder and coating in other package under the same conditions of luminous flux - 10% - 20% of the difference. Below we first to get to know the phosphor, luminous principle, to explore the selection and preparation of phosphor.

1, the phosphor by subject lattice ( hostlattice’H） With the activation center ( activator’coA） Composition, and auxiliary activator or sometimes referred to as sensitizer. Subject lattice: play the role of transmitting energy in the process of excitation. For example: Y3AI5O12: Ce3 + the Y3AI5O12. The activation center: lattice can activate the subject such as Y3AI5O12: Ce3 + the Ce3 +.

phosphor luminescence principle: power type GaN base blue chips as pump sources are used to stimulate phosphor powder, produced by the excited electrons directly in the form of light back to the electronic ground state.

rational selection rules of phosphor powder particle size, density, morphology, luminance value and excitation wavelength of LED luminous efficiency and color rendering has a great influence; Luminous efficiency and the relationship between the wavelength is, only under the condition of two composite white light wavelength, 450 nm and 580 nm can obtain maximum efficiency. Three wavelength selected wavelength of 450 nm, 540 nm and 610 nm particles is large, most efficient good luminous efficiency can shading, settling quickly, not easily encapsulated; Particles moderate good luminous efficiency will sink, packaging more easily; Nano particles not easy sedimentation, easier encapsulation, but luminous efficiency is low.

2, white LED light source color rendering in the lighting control

is the light source color rendering of objects real color degree. The sun radiation and halogen lamps are continuous spectrum, in the wavelength of visible light, 380 - 780海里) Range, with red, orange, yellow, green, green, blue, violet wait for all sorts of color and color rendering index is classified as Ra100.

the sun as a standard light source, compared with the above a few kinds of artificial light found: halogen lamps and lanterns has a continuous spectrum, showed better color rendering, continuous is not good, the rest of the two kinds of light source spectrum energy distribution is not balanced and poor color rendering. To improve by leds emit blue light stimulate phosphor synthesis of white light source color rendering, must adjust its spectrum, continuous and balanced in visible light. Through a lot of our experiment several improved methods: color, around 6500 k color temperature range to do color rendering index > 80, need to select the appropriate phosphors and excitation wavelength; In blue light LED excitation YAG phosphors emission on the basis of yellow green + red phosphors to compensate for the shortcomings of the original spectrum red, you can improve this kind of light source color rendering; Optimizing YAG phosphors, with different phosphor emission spectroscopy complementary illuminant, can also improve this kind of light source color rendering. Nodule

has gained a foothold in the field of lighting, LED in the decorative lighting, accent lighting and atmosphere build has a unique advantage. In future applications, should seize the advantage of LED, reasonable application of LED, at the same time, through further research of key technology, further development of LED application in general lighting. In terms of the needs of the visual function, the LED luminous flux, luminous efficiency and color rendering, in order to satisfy the application of large area lighting needs further improvement. For lehman photoelectric is willing to work with peers, LED research unit jointly make the LED light source is suitable for living a healthy and comfortable light environment to make a positive role.