CN101697367B - 一种利用透明陶瓷制备led的方法 - Google Patents

一种利用透明陶瓷制备led的方法 Download PDF

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CN101697367B
CN101697367B CN200910235312.XA CN200910235312A CN101697367B CN 101697367 B CN101697367 B CN 101697367B CN 200910235312 A CN200910235312 A CN 200910235312A CN 101697367 B CN101697367 B CN 101697367B
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transparent ceramic
led
ceramic
fluorescence
chip
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CN101697367A (zh
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雷牧云
李祯
赵艳民
娄载亮
***
宋庆海
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Sinoma Intraocular Lens Research Institute Co ltd
Beijing Sinoma Synthetic Crystals Co Ltd
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BRIGHT CRYSTALS Tech Inc
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Abstract

本发明公开了一种利用透明陶瓷制备LED的方法,具体为:将设定量的荧光粉加入到透明陶瓷粉体中,荧光粉的掺入比例为0.01到100wt.%;将原料充分混合后,采用陶瓷制备工艺制备出荧光透明陶瓷;将制备出的荧光透明陶瓷和半导体芯片组装形成LED器件。本发明通过用荧光透明陶瓷取代传统LED中的荧光粉层和环氧树脂封装外壳,将荧光透明陶瓷和LED芯片组装成新型LED器件,荧光透明陶瓷具有封装外壳和荧光材料的双重作用,使得通过本发明方法制作的LED器件性能会更加优异。

Description

一种利用透明陶瓷制备LED的方法
技术领域
本发明涉及LED领域,尤其是一种利用透明陶瓷制备LED的方法。
背景技术
目前,使用较多的LED制备技术是将蓝光或紫外光等LED芯片与荧光粉层、环氧树脂外壳进行封装,通过调整芯片的种类、荧光粉的成分和比例,发出红、橙、黄、绿、蓝等多种色光以及白色光。
对现有技术而言,LED的组成和结构,存在一些关键问题急需解决。
现有LED芯片采用涂覆荧光粉的方法实现波长转换,但LED的持续点亮会造成温度升高,荧光粉和树酯材料会发生退化,并且LED芯片发出的光通过波长转换材料时会发生散射、吸收等现象,从而降低了出光效率,需改善波长转换材料在高温下的衰减问题。受树脂外壳的热稳定性所限,环氧树脂外壳不能承受LED长期工作,导致现有LED很难适用于高功率和高温环境的使用,很大程度上限制了其应用范围。
人们对LED用作照明光源的色品质有着严格的要求,主要体现在相关色温、色坐标、显色指数以及均匀性等性能。现有白光LED采用荧光粉涂敷工艺,该工艺会产生“色圈”和“色斑”问题。虽然加入光散射剂会改善这一光色不均匀性状况,但这样又会导致光强和光通降低。同时涂覆厚度不均匀也会严重影响其发光性能。
发明内容
针对现有技术存在的问题,本发明的目的在于提供一种通过制备荧光透明陶瓷,替代封装荧光粉层和环氧树脂外壳的现有LED技术,并且工艺操作可靠性高的利用透明陶瓷制备LED的方法。
为实现上述目的,本发明一种利用透明陶瓷制备LED的方法,具体为:
1)将设定量的荧光粉加入到透明陶瓷粉体中,荧光粉的掺入比例
为0.01到100wt.%;
2)将原料充分混合后,采用公知的陶瓷制备工艺制备出荧光透明陶瓷;
3)将制备出的荧光透明陶瓷和半导体芯片组装形成LED器件。
进一步,所述步骤1)中的荧光粉包括黄色荧光粉、红色荧光粉、绿色荧光粉、橙色荧光粉、蓝色荧光粉、紫色荧光粉中的一种、或多种按比例混合而成。
进一步,所述步骤1)中透明陶瓷粉体的材质为镁铝尖晶石、钇铝石榴石、氧化钇、氮氧化铝、氧化铝、硫化锌、氧化锆、氧化镧钇、铪酸锶、氧化镁、氧化铍、氧化钇-二氧化锆、砷化镓、硫化锌、硒化锌、氟化镁、氟化钙、氧化钪、氧化镥、氧化钆中的一种。
进一步,所述步骤2)中混合后的原料需进行干燥处理。
进一步,所述步骤2)中的陶瓷制备工艺包括真空热压、真空烧结、无压烧结、微波烧结、热等静压、SPS或激光烧结。
进一步,所述步骤2)中制备的荧光透明陶瓷的烧结体需在设定温度范围内进行退火处理,之后实施热等静压,然后进行粗磨、细磨、抛光而得到荧光透明陶瓷。
进一步,所述步骤3)中的半导体芯片包括蓝光LED芯片、紫外光LED芯片、绿光LED芯片、红光LED芯片或黄光LED芯片,通过选择不同发光颜色的半导体芯片与不同发光颜色的荧光粉,使其发光混合成多种色光。
本发明通过用荧光透明陶瓷取代传统LED中的荧光粉层和环氧树脂封装外壳,将荧光透明陶瓷和LED芯片组装成新型LED器件,荧光透明陶瓷具有封装外壳和荧光材料的双重作用,使得通过本发明方法制作的LED器件性能会更加优异。
具体实施方式
本发明一种利用透明陶瓷制备LED的方法,首先将适量荧光粉加入到透明陶瓷粉体中进行充分混合,其中荧光粉包括黄色荧光粉、红色荧光粉、绿色荧光粉、蓝色荧光粉、紫色荧光粉中的一种、或多种按比例混合而成,透明陶瓷粉体包括镁铝尖晶石、钇铝石榴石、氧化钇、氮氧化铝、氧化铝、硫化锌、氧化锆、氧化镧钇、铪酸锶、氧化镁、氧化铍、氧化钇-二氧化锆、砷化镓、硫化锌、硒化锌、氟化镁、氟化钙、氧化钪、氧化镥、氧化钆等,并且荧光粉的掺入比例为0.01到100wt.%。
采用陶瓷的制备工艺,如真空热压、真空烧结、无压烧结、微波烧结、热等静压等,制备出荧光透明陶瓷。将制备出的荧光透明陶瓷和半导体芯片组装形成LED器件,取代现有的荧光粉涂覆到树酯或玻璃层的封装工艺。其中半导体芯片包括蓝光LED芯片、紫外光LED芯片、绿光LED芯片或红光LED芯片,通过选择不同发光颜色的半导体芯片与不同发光颜色的荧光粉,使其发光混合成多种色光。
透明陶瓷材料,如MA(镁铝尖晶石)、YAG(钇铝石榴石)、氧化钇、氧化铝等,该类材料具有良好的耐腐蚀性和绝缘性,高热导率、高熔点、高硬度、高强度、以及透光性能优良的特点,其优异的性能可使由其制成的器件环境适应性强,耐磨损、抗冲击,经过长时间使用,透明陶瓷材料表面损伤少,仍可保持高透过率,是理想的封装光学材料。
本发明中利用LED芯片发出的光激发荧光透明陶瓷中的荧光成分,如利用蓝光LED芯片发出的蓝光,激发荧光透明陶瓷中的Ce:YAG荧光粉,使其发射黄光,该黄光和透过透明陶瓷的剩余蓝光混合成白光。
当荧光粉的掺入比例为100%时,即将掺杂发光离子的透明陶瓷粉既作为发光物质,又充当陶瓷基体,可将此粉体制备出的透明陶瓷直接用于LED封装,例如将Ce:YAG透明陶瓷与蓝光芯片直接用于白光LED封装,此时,铈离子含量从0.01at.%到30at.%,使用时根据要求可同时调节陶瓷体的厚度。
用荧光透明陶瓷取代传统LED中的荧光粉层和环氧树脂封装外壳,它和LED芯片组装成新型LED器件。这里荧光透明陶瓷具有双重身份:1.封装外壳;2.荧光材料。这种新型的LED器件性能会更加优异,具体表现在如下方面:
(1)作为外壳:
透明陶瓷热导率高、散热快:LED同样电流情况下温升小,LED的发光波长变化小、发光强度减少的少;可以提高工作电流,提高发光强度;
透明陶瓷耐高温、透明度高,因而可降低LED的荧光损失,使器件更耐磨损、抗冲击,适于高温环境应用,使用寿命长;
透明陶瓷力学性能好、使器件更耐磨损、抗冲击,经过长时间使用,表面损伤少,保持高透过率,使用寿命长。
(2)作为荧光材料:
荧光透明陶瓷的荧光性能比荧光粉的更加优异,提高了均匀性,因而可以提高LED器件的发光性能。
可根据芯片的功率、发射波长、所需的色品、色温等要求,选取荧光粉的吸收峰值和发射峰值,得到不同出光。
可以改变荧光粉的种类,配合不同的芯片,制成的LED不局限于发射白光,调节荧光粉的比例和制成陶瓷的厚度调节性能参数。
实例1:
以利用MA(镁铝尖晶石)透明陶瓷制备白光LED为例。
1)粉体制备:将2wt.%的Ce:YAG黄色荧光粉加入到MA透明陶瓷粉体中,通过湿法球磨充分混合,干燥后获得荧光透明陶瓷粉体;在粉体制备过程中如果采用干法制备混合物,就不需要经过干燥处理,将其充分混合后即得到荧光透明陶瓷粉体。
2)成型过程:将添加助烧剂的荧光透明陶瓷粉体进行真空热压成型,得到荧光透明陶瓷烧结体;将以上烧结体在一定温度范围内退火处理,之后实施热等静压,然后进行粗磨、细磨、抛光,即得到MA荧光透明陶瓷;
3)LED封装:将制备出的MA荧光透明陶瓷和蓝光半导体芯片组装形成LED器件。
电光源测试结果:
色品坐标:x=0.346,y=0.353
色温:Tc=4967K
显色指数:Ra=72
光效率:η=76lm/w
利用蓝光LED芯片发出的蓝光,激发荧光透明陶瓷中的Ce:YAG荧光粉,使其发射550~580nm的黄光,该黄光和通过透明陶瓷的剩余蓝光混合成白光。可通过调节荧光透明陶瓷中的荧光粉化学成分和掺杂量以及陶瓷片的厚度,用以产生不同相关色温和显色指数的白光。
可根据芯片的功率、发射波长、所需的色品、色温等要求,选取荧光粉的吸收峰值和发射峰值,得到不同的出光。
可以改变荧光粉的种类,配合不同的芯片,制成的LED不局限于发射白光。
本发明中的荧光透明陶瓷制备工艺不限于热压烧结、热等静压的制备方法。
实例2
以利用氧化钇透明陶瓷制备白光LED为例。
1)粉体制备:将3wt.%的Ce:YAG黄色荧光粉加入到氧化钇透明陶瓷粉体中,通过湿法球磨充分混合,干燥后获得荧光透明陶瓷粉体;
2)成型过程:将添加助烧剂的荧光透明陶瓷粉体进行真空热压成型,得到荧光透明陶瓷烧结体;将以上烧结体在一定温度范围内退火处理,之后实施热等静压,然后进行粗磨、细磨、抛光,即得到氧化钇荧光透明陶瓷;
3)LED封装:将制备出的氧化钇荧光透明陶瓷和蓝光半导体芯片组装形成LED器件。
电光源测试结果:
色品坐标:x=0.392,y=0.363
相关色温:Tc=3597K
显色指数:Ra=67
光效率:η=63lm/w
实例3
以利用Ce:YAG透明陶瓷制备白光LED为例。
将含铈离子2wt.%的Ce:YAG透明陶瓷直接用于LED封装,Ce:YAG透明陶瓷与蓝光LED芯片组装形成白光LED器件。
电光源测试结果:
色品坐标:x=0.339,y=0.325
色温:Tc=5179K
显色指数:Ra=73
光效率:η=75lm/w
实例4
以利用MA透明陶瓷制备三波长白光LED为例。
1)粉体制备:按0.4wt.%、2wt.%、0.2wt.%的比例,将绿色、黄色、红色荧光粉加入到MA透明陶瓷粉体中,通过湿法球磨充分混合,干燥后获得荧光透明陶瓷粉体;
2)成型过程:将添加助烧剂的荧光透明陶瓷粉体进行真空热压成型,得到荧光透明陶瓷烧结体,将以上烧结体在一定温度范围内退火处理,之后实施热等静压,然后进行粗磨、细磨、抛光,即得到MA荧光透明陶瓷;
3)LED封装:将制备出的MA荧光透明陶瓷和蓝光半导体芯片组装形成LED器件。
电光源测试结果:
色品坐标:x=0.321,y=0.347
相关色温:Tc=5997K
实例5
以利用MA透明陶瓷制备红色LED为例。
1)粉体制备:按0.5wt.%的比例,将红色荧光粉加入到MA透明陶瓷粉体中,通过湿法球磨充分混合,干燥后获得荧光透明陶瓷粉体;
2)成型过程:将添加助烧剂的荧光透明陶瓷粉体进行真空热压成型,得到荧光透明陶瓷烧结体,之后实施热等静压,然后进行粗磨、细磨、抛光,即得到MA荧光透明陶瓷;
3)LED封装:将制备出的MA荧光透明陶瓷和紫外半导体芯片组装形成红色LED器件。
电光源测试结果:
色品坐标:x=0.653,y=0.337
色温:Tc=3060K
实例6
以利用氧化钇透明陶瓷制备绿色LED为例。
1)粉体制备:将1.5wt.%的绿色荧光粉加入到氧化钇透明陶瓷粉体中,通过湿法球磨充分混合,干燥后获得荧光透明陶瓷粉体;
2)成型过程:将添加助烧剂的荧光透明陶瓷粉体进行真空热压成型,得到荧光透明陶瓷烧结体,然后进行粗磨、细磨、抛光,即得到氧化钇荧光透明陶瓷;
3)LED封装:将制备出的氧化钇荧光透明陶瓷和紫外半导体芯片组装形成绿色LED器件。
电光源测试结果:
色品坐标:x=0.365,y=0.603
相关色温:Tc=4996K

Claims (6)

1.一种利用透明陶瓷制备LED的方法,具体为:
1)将掺入比例为100wt.%的荧光粉作为透明陶瓷粉;
2)将原料充分混合后,采用真空热压、真空烧结、无压烧结、微波烧结或热等静压的陶瓷制备工艺制备出荧光透明陶瓷;
3)将制备出的荧光透明陶瓷和半导体芯片组装形成LED器件;其中,当荧光粉的掺入比例为100%时,即将掺杂发光离子的透明陶瓷粉既作为发光物质,又充当陶瓷基体,此粉体制备出的透明陶瓷直接用于LED封装。
2.如权利要求1所述的利用透明陶瓷制备LED的方法,其特征在于,将Ce:YAG透明陶瓷与蓝光芯片直接用于白光LED封装,此时,所述荧光粉中铈离子含量从0.01at.%到30at.%,使用时根据要求可同时调节陶瓷体的厚度。
3.如权利要求1所述的利用透明陶瓷制备LED的方法,其特征在于,所述步骤2)中混合后的原料需进行干燥处理。
4.如权利要求1所述的利用透明陶瓷制备LED的方法,其特征在于,所述步骤2)中的陶瓷制备工艺还包括SPS或激光烧结。
5.如权利要求1所述的利用透明陶瓷制备LED的方法,其特征在于,所述步骤2)中制备的荧光透明陶瓷的烧结体需在设定温度范围内进行退火处理,之后实施热等静压,然后进行粗磨、细磨、抛光而得到荧光透明陶瓷。
6.如权利要求1所述的利用透明陶瓷制备LED的方法,其特征在于,所述步骤3)中的半导体芯片包括蓝光LED芯片、紫外光LED芯片、绿光LED芯片、红光LED芯片或黄光LED芯片,通过选择不同发光颜色的半导体芯片与不同发光颜色的荧光粉,使其发光混合成多种色光。
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