Composite structure Al_(2)O_(3)/Al_(2)O_(3)-YAG:Ce/YAG ceramics with high color spatial uniformity for white laser lighting

Composite ceramic phosphor(CCP)is a candidate light-conversion material to obtain the high-quality laser lighting source.Phosphors based on the transmissive configuration model could not simultaneously meet the requirements of angular color uniformity and high thermal stability.In this study,a novel composite structure ceramic was designed,including Al_(2)O_(3)-YAG:Ce/YAG layered ceramic with a size of 1 mm×1 mm for lighting,and Al_(2)O_(3) ceramic(φ=16.0 mm)was used as the wrapping material due to its outstanding thermal stability.The prepared ceramics exhibited excellent thermal performance and no yellow ring phenomenon.Through this design,we achieved the match of the intensity distribution of the blue and yellow lights,resulting in a high angular color uniformity of 0.9 with a view angle of±80°.All ceramics showed no luminous saturation phenomenon,even the laser power density was increased up to 47.51 W/mm^(2).A high-brightness white-light source with a luminous flux of 618 lm,a luminous efficiency of 126 lm/W,a CCT of 6615 K,and a CRI of 69.9 was obtained in the transmissive configuration.In particular,the surface temperature of the ceramic was as low as 74.1℃ under a high laser radiation(47.51 W/mm^(2)).These results indicate that Al_(2)O_(3)/Al_(2)O_(3)-YAG:Ce/YAG composite structure ceramic is a promising luminescent material in the high-power laser lighting applications.

Recent progress on garnet phosphor ceramics for high power solid-state lighting

As the fourth-generation light source,solid-state lighting has developed rapidly in the past 30 years due to its advantages of high efficiency and environmental protection.It is widely used in various scenes such as automobile headlights,projection displays,industrial production,and remote lighting.High-power,high-brightness white light-emitting diodes(LEDs)and laser diodes(LDs)technology put forward new requirements for the service stability of color conversion materials.Garnet phosphor ceramics have emerged with their unique advantages of withstanding high power excitation density and the flexibly tunable spectrum.In this article,the research progress of garnet based phosphor ceramics for high-power solid-state lighting was comprehensively reviewed.Firstly,the band gap and coordination environment regulations of luminescence centers of garnet phosphor were summarized.Secondly,the improvement of luminous efficacy via defects regulation was discussed.Thirdly,the relationship between the geometric design and the lighting performance was elucidated.Fourthly,the characterization methods of phosphor ceramics for laser lighting were introduced and illustrated.Finally,the development trend of garnet phosphor ceramics in solid state lighting and display was prospected.