| abstract |
The invention discloses a light-emitting device, comprising a carrier plate with a first surface and a second surface opposite to the first surface, and a light-emitting unit arranged on the first surface, which emits light toward but does not pass through first surface. The light-emitting device can measure a first brightness above the first surface, and can measure a second brightness below the second surface. The ratio of the first brightness to the second brightness is 2-9. |