| 摘要 |
A wavelength-converting device (2) used for converting first waveband light (L1) includes a transmissive substrate (20), a phosphor layer (22) and an optical layer (21). The transmissive substrate (20) has a refraction coefficient n s , the refraction coefficient n s is greater than an environmental refraction coefficient n amb . The phosphor layer (22) is disposed over a side of the transmissive substrate (20) for converting the first waveband light (L1) into second waveband light (L2). The optical layer (21) is disposed over the other side of the transmissive substrate (20) opposite to the phosphor layer (22) for reflecting the second waveband light (L2). The optical layer (21) has an effective refraction coefficient n r . The relation between n s , n amb and n r is given by n r >2(n amb 2 )/n s . As a result, the light leakage is avoided, the fabrication is simplified, and the difficulty of material selection is reduced. |
