Author Affiliations
Abstract
1 School of Physics and Electronic Electrical Engineering, Huaiyin Normal University, Huaian 223001, China
2 School of Science, Nanjing University of Science and Technology, Nanjing 210094, China
The apatite compound Ca4La6(SiO4)4(PO4)2O2 (CLSPO) was explored as the host material for phosphors used in white light-emitting diodes (wLEDs). The crystal structure of the CLSPO host prepared by the solid-state reaction method was investigated with Rietveld refinement. The rare earth ions (Eu3+/ Tb3+/Ce3+, Tb3+/Tb3+, Mn2+) activated CLSPO phosphors were synthesized, and their photoluminescence properties, quantum yields, as well as thermal stabilities, were studied. Under near-ultraviolet excitations, the Eu3+ and Tb3+-doped CLSPO compounds exhibited red and green emissions with high luminescence efficiencies. Besides, tunable emissions from green to orange were obtained by introducing Mn2+ ions into the Tb3+-doped CLSPO samples. The results showed that the phosphors studied may have potential applications for wLEDs.
160.4760 Optical properties 230.3670 Light-emitting diodes 300.6170 Spectra Chinese Optics Letters
2019, 17(5): 051602
Author Affiliations
Abstract
1 School of Science, Nanjing University of Science and Technology, Nanjing 210094, China
2 School of Physics and Electronic Electrical Engineering, Huaiyin Normal University, Huai’an 223001, China
A series of RE3+ (RE=Eu/Tb/Ce)-activated Sr4La(PO4)3O (SLPO) phosphors are synthesized with a high-temperature solid-state reaction method. The photoluminescence properties, thermal stability, morphology, and CIE values of the SLPO:Eu3+/Tb3+/Ce3+ phosphors are investigated. Under 394 nm excitation, the SLPO:Eu3+ exhibits red emission, and the SLPO:Tb3+ presents a green emission upon 379 nm excitation, while Ce3+-doped SLPO has a broad emission band ranging from 370 to 650 nm under 337 nm excitation. The investigation results indicate that the SLPO:Eu3+/Tb3+/Ce3+ phosphors can be effectively excited by near-ultraviolet light and may have the potential to serve as red-, green-, and blue-emitting phosphors for applications in white light-emitting diodes.
160.4760 Optical properties 230.3670 Light-emitting diodes Chinese Optics Letters
2017, 15(12): 121602
1 南京理工大学近程高速目标探测技术国防重点学科实验室, 江苏 南京 210094
2 淮阴师范学院江苏省现代检测技术与智能系统重点建设实验室, 江苏 淮安 223300
针对传统的采用发散照明的相位测量轮廓术投影到参考面上的光场产生畸变的情况, 提出一种利用逆推法从参考面上的位置坐标与光栅条纹坐标分布之间的映射关系建立投影光栅模型的方法, 确保校正光栅投影到参考面上的条纹满足周期性分布。通过相位-高度映射关系恢复出被测物体的面形分布。该方法无须像传统测量方法一样将相位-高度之间的映射关系以数据表形式存储在计算机中, 放宽了系统测量的约束条件, 简化了测量装置, 并能实现高精度测量。计算机模拟和实验均证实了该方法的有效性。
测量 三维测量 光栅投影 相位测量轮廓术 逆推法 激光与光电子学进展
2017, 54(1): 011202
四川大学 光电科学技术系,四川 成都 610064
提出一种基于反向摄影的光学坐标测量方法。测量系统主要由微型摄像机、测杆和液晶显示器组成。测杆的一端固定微型摄像机,另一端是一个触发测头,液晶显示器上显示的是二维正弦条纹图。测量时,将液晶显示屏置于被测物体周围,触发测头接触被测物体表面,摄像机摄取显示器上的条纹图像。通过条纹图中所携带的相位信息确定摄像机主点在世界坐标系中的空间坐标和姿态,采用最小二乘优化的方法来获得测头在摄像机坐标系内的空间坐标,由此可以得到测头与被测物体点在世界坐标系中的三维坐标。实验结果表明,该方法简单、可靠,可以准确地得到光学坐标测量结果。
测量 光学坐标测量 反向摄影 摄像机标定 坐标变换 最小二乘优化
四川大学 光电科学技术系,四川 成都 610064
提出一种利用投影仪条纹投影技术完成三维坐标测量的方法。测量系统包括两部分:一是可以在三维坐标内自由移动的测头,另一个就是静止不动的面阵探测阵列。移动的测头上有微型投影仪,形成的投影条纹由面阵探测器接收。应用相移算法精确测量探测器上的相位,并结合几何系统模型通过最优化方法确定测头的xyz坐标。给出了测量原理、迭代求解方法、计算机模拟和初步实验结果。实验中,微型投影装置投影相移条纹由面阵探测器接收,利用相移条纹计算出的相位分布具有很高的精度和较强的抗噪声能力,为后续的迭代优化计算提供了基础。实验结果表明,该测量方法具有较高的测量精度。
光学测量 条纹投影 相移算法 最优化
