Progress in Research on Transparent Ceramics for 3D Printing Laser Illumination at Shanghai Institute of Optics and Mechanics

It is reported that the Research Center for Infrared Optical Materials of the Chinese Academy of Sciences Shanghai Institute of Optics and Fine Mechanics has made progress in the research of additive manufacturing (3D printing) transparent ceramics for laser illumination.

Recently, the Research Center for Infrared Optical Materials of the Shanghai Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, has made progress in the research of additive manufacturing (3D printing) transparent ceramics for laser illumination. This work achieved 3D printing of high-density cerium activated lutetium aluminum garnet (LuAG: Ce) ceramics for laser illumination using digital light processing printing technology (DLP). Laser illuminated transparent ceramics with complex geometric structures were manufactured using 3D printing technology, breaking through the limitations of traditional ceramic molding techniques. The relevant research results are titled 3D Printing of LuAG: Ce Transparent Ceramics for Laser driven Lighting and published in Ceramics International.

Laser lighting systems can achieve high output efficiency (100-1000 times that of light-emitting diodes) at high power densities, allowing laser driven lighting systems to provide advantages for future solid-state lighting, such as high brightness, compact size, and directional lighting. However, traditional preparation processes can only produce simple geometric shapes, which cannot meet the needs of laser driven solid-state lighting devices with complex optical structures. 3D printing technology can achieve rapid mold free manufacturing, and all components can be digitally designed, bringing important possibilities to the field of luminescent transparent ceramic manufacturing.

Researchers have developed a photocurable ceramic ink for DLP, which is used to manufacture laser driven illumination cerium activated lutetium aluminum garnet (LuAG: Ce) luminescent transparent ceramic components with high printing resolution. The ink used for DLP printing has a solid content of up to 50 vol% and excellent shear thinning performance. The study introduced luminescent dyes into DLP ink to reduce the excessive curing width effect caused by the scattering of ultraviolet light by ceramic powder. Researching the use of DLP 3D printing method to manufacture LuAG: Ce ceramic bodies with customizable centimeter level complex 3D geometric shapes.

After sintering, the relative density of 3D printed ceramic components reached 96.4% and exhibited excellent light transmittance (about 40%). Laser excitation experiments have confirmed that the 3D printed LuAG: Ce transparent ceramics have a high laser flux threshold (19.22 W mm-2), which is related to their unique microchannel structure on the surface. The experiment shows that the application of LuAG: Ce LTCs 3D printing technology with free geometric structure design and high laser flux threshold provides a more efficient and reliable solution for high-power laser driven lighting.

Figure 1. (a) Schematic diagram of DLP 3D printed transparent ceramic body; Printed photos of LuAG: Ce ceramic bodies: (b) honeycomb, (c) minimum surface, (d) super hemisphere, and (e) different sizes of super hemisphere. (f) 3D printed sintering process diagram of LTC; (g) Laser lighting device; (h) Polished 3D printed LTC placed on the letter "SIOM" under sunlight; (i) Transmittance spectrum; (j) Sintered ultra hemispherical 3D printed LTC encapsulated in LD lighting chips.

Figure 2. (a) Experimental schematic diagram for testing curing thickness and curing width; (b) SEM images and particle size distribution of ceramic powders (illustrated); (c) The rheological behavior of printable ceramics with a solid content of 50 Vol.%; (d) The relationship between the curing depth of methyl orange ink with different concentrations and the dose of ultraviolet radiation; (e) The relationship between the curing width of different concentrations of methyl orange ink and the ultraviolet radiation dose is shown in the following photos, which correspond to the curing conditions of different concentrations of methyl orange ink; (f) 3D printing of green body layer structure.

Figure 3. The microstructure evolution of the printed body during drying at 100 ° C, pre sintering at 1200 ° C, vacuum sintering at 1800 ° C, and cross section heat treatment after vacuum sintering. (e) The thermally etched transparent ceramic surface after polishing and elemental mapping.

Figure 4. Laser lighting performance and packaging application of LuAG: Ce ceramics.

Source: Shanghai Institute of Optics and Precision Machinery