Preparation Of LED Fluorescent Glass By Screen Printing And Its Performance Study

In the process of lighting development,LED is frequently used in a variety of life,study,work scenes.It has the advantages of safety,stability,energy saving,and environmental protection,which provides a lot of convenience for people.However,with the deepening of the research on LED and more requirements of lighting quality.Problems of LED need to be solved.The LED products on the market currently are mainly made of a combination of yellow YAG phosphors and blue chips.The glue coating method leads to obvious glare effect and blue light hazard.After working for a long time and increasing the power,the phosphor temperature quenching,silica gel yellowing,poor thermal stability,reduced light efficiency,life reduction and other problems caused by the LED seriously affect the application and development.Therefore,this paper uses the screen printing method to prepare a kind of fluorescent glass,through the way of remote flip combination with the chip to prepare the imitation of natural light LED devices.The screen printing method converts a point light source into a surface light source,which avoids the glare effect.The remote flip way solves the heat dissipation problem and improves the thermal stability.The imitation natural light fluorescent glass can reduce the harm of blue light and meet the requirement of modern lighting.First,the YAG:Ce,Sr Ga₂S₄:Eu,Ca S:Eu three-color phosphors were mixed with low glass powder to form a slurry,which was coated on the rough surface of the ground glass by screen printing,and co-sintered at low temperature to form fluorescent glass.The optimal sintering time,temperature and ratio of fluorescent glass were determined by fluorescence spectroscopy and transmission spectroscopy.The prepared fluorescent glass and 460 nm blue chip were combined in a remote flip way to form a LED device.The optical properties were tested by spectral scanner,and the measured color coordinates were（0.3101,0.3483）,（0.2107,0.4007）,（0.2938,0.1111）.The color temperature was 4999 K,6532 K and 2333 K respectively.Secondly,based on the above research,the imitation natural light fluorescent glass was prepared.By adjusting the proportion of YAG:Ce,Ba Si₂N₂O₂:Eu and Ca S:Eu phosphors,the multi-light color composite chip was designed to test the influence of voltage and carry out stability test to achieve the effect of imitation natural light.Under the optimal experimental conditions,the color rendering index,light efficiency,color temperature and color coordinate of the glass were 97,85Lm/W,5285 K and（0.3381,0.3586）,which were close to the color coordinate of natural light.The spectra of the glass excited by the composite chip were similar to the spectra of sunlight.To achieve the effect of imitation of natural light.