Research On Spatial Uniformity Of Photon Flux Density For Pc-LEDs

With the development of the times,people have become more and more demanding of lighting sources.In recent years,people are not only in pursuit of high light efficiency,but pay more attention to the quality of light sources,and the pursuit of spatial uniformity of light distribution is a top priority.The spatial uniformity of light distribution includes the spatial homogeneity of a series of parameters such as the intensity of light intensity.The essence is to study the uniform distribution of the photon flux density of each color spectral component of different light emission angles,and the ratio of each color band also needs to be maintained.Consistently,this is of great significance for both white light and plant lighting.The pursuit of high-quality lighting requires optimization and improvement of the light source device,and pc-LEDs as a mainstream lighting device,the structure of the phosphor coating is directly related to the quality of the lighting,and the improvement of its coating structure directly affects the quality of the light source.The essential.The focus of the study on the uniformity of the photon flux density in each band of the lighting characteristics is the study of the phosphor coating structure.In this paper,a relatively uniform spatial light distribution is obtained through the improvement of the coating structure.Since all the light emitted by the device is emitted by the chip,the light intensity attenuates with the increase of the angle due to the Lambertian distribution of the chip emission,which is the main reason for the non-uniform light distribution.In order to improve the spatial light distribution emitted by the chip,the light extraction layer(remote layer)not only functions to separate the phosphor from the chip and extract light,but also is improved the spatial light distribution into the phosphor layer under a certain range.In the experiment,an adaptive light extraction layer(remote layer)is obtained by using self-exposure technology,and the relationship between the light extraction layer and the photon flux density density obtained under different exposure times is analyzed,and the photon flux density is well-proportioned in the range of 0 to 60°in the spatial angle.The adaptive light extraction layer improves the uniformity of the blue light emitted by the chip,and the proportion of quantum numbers in each color band in each angle in the space must be kept the same,that is,the conversion rate of the phosphor-converting blue light from each angle is kept consistent.Therefore,the self-exposure technology is used again.Applying a phosphor layer,a new dual-protection type adaptive coating was proposed.Compared with a single adaptive phosphor coating,the new structure exhibits a more sta ble yellow-blue ratio at all spatial angles,with a proportional deviation of only 0.28.Similarly,the color temperature deviation is only 98 K,which is 106 K lower than the self-adaptive structural color temperature deviation of 204 K.The light efficiency of the dual-protection self-adaptive coating structure is also improved by 10% compared with the adaptive structure.After aging test,the new structure obviously has a smaller yellow-blue light-substance ratio attenuation with the aging time,and the deviation of the ratio remains almost unchanged.In order to meet the high-quality white light illumination and enhance the color rendering of the light source,the color rendering properties of the 620 nm red CdSe quantum dots mixed with silica gel were increased on the basis of the yellow phosphor and the blue chip.The color rendering has been significantly improved,both Ra and R9 are over 85,close to 90 or so.First,the colloidal quantum dot layer was coated on a dual-protection type self-adaptive coating structure by a free dispensing method(conventional dispensing method).Although the color rendering property was enhanced,the spatial uniformity could not be guaranteed.In order to obtain a conformable colloid The quantum dot layer,evenly coated with equal thickness colloidal quantum dot layers on the original double-preservation type adaptive coating structure,obtains a photon quantum flux density ratio of each color band that is relatively uniform under each spatial angle.At the same time,the device also ensures the uniformity of color temperature and color rendering index in space angle.