Angle-resolved photoluminescence spectrum of a uniform phosphor layer
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- Ichiro Fujieda
- Department of Electrical and Electronic Engineering, Ritsumeikan University , Kusatsu 525-8577, Japan
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- Masamichi Ohta
- Department of Electrical and Electronic Engineering, Ritsumeikan University , Kusatsu 525-8577, Japan
説明
<jats:p>A photoluminescence spectrum depends on an emission angle due to self-absorption in a phosphor material. Assuming isotropic initial emission and Lambert-Beer’s law, we have derived simple expressions for the angle-resolved spectra emerging from the top and bottom surfaces of a uniform phosphor layer. The transmittance of an excitation light through the phosphor layer can be regarded as a design parameter. For a strongly-absorbing phosphor layer, the forward flux is less intense and more red-shifted than the backward flux. The red-shift is enhanced as the emission direction deviates away from the plane normal. When we increase the transmittance, the backward flux decreases monotonically. The forward flux peaks at a certain transmittance value. The two fluxes become similar to each other for a weakly-absorbing phosphor layer. We have observed these behaviors in experiment. In a practical application, self-absorption decreases the efficiency of conversion and results in angle-dependent variations in chromaticity coordinates. A patterned phosphor layer with a secondary optical element such as a remote reflector alleviates these problems.</jats:p>
収録刊行物
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- AIP Advances
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AIP Advances 7 (10), 105223-, 2017-10-01
AIP Publishing
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詳細情報 詳細情報について
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- CRID
- 1360567183875627520
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- ISSN
- 21583226
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- 資料種別
- journal article
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- データソース種別
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- Crossref
- KAKEN
- OpenAIRE