this application relates to a light - emitting device comprising a light channel having an upper surface , a lower surface opposite to the upper surface , an inner surface intersecting with each of the upper and lower surface by different angles , and an escape surface ; and a light - emitting element having a bottom surface substantially parallel to the inner surface and emitting light traveling inside the light channel toward the escape surface . in an embodiment , the escape surface of the light - emitting device is an inclined plane with lens array thereon .