| 摘要 |
A light-emitting device comprises: a substrate having a first side and a second side opposite to the first side; a light-emitting stack disposed on the first side and emitting a light having a main wavelength ofλnm; wherein the substrate comprises a first surface on the first side, the first surface comprising a first pattern arranged with a first period, the first pattern comprising a second pattern arranged with a second period; and the first period is greater than 6λ, and the second period is smaller thanλnm. |
