An illumination device, comprising: a supporting structure having a hole; a first light emitting element; and a second light emitting element, wherein the first and second light emitting elements are inserted into or bonded with the supporting structure, characterized in that the first light emitting element comprises: a first transparent substrate having a first support surface, a first rear surface opposite to the first support surface, a first top surface extending along a shorter edge of the first support surface and a shorter edge of the first rear surface, and a first side surface extending along a longer edge of the first support surface and a longer edge of the first rear surface; and a first plurality of LED chips (3; 14) disposed on the first support surface, each LED chip of the first plurality of LED chips having a first substrate, a first N-type semiconductor layer, a first active layer and a first P-type semiconductor layer, first substrate being arranged between the first N-type semiconductor layer and the first transparent substrate, that the second light emitting element comprises: a second transparent substrate having a second support surface, a second rear surface opposite to the second support surface, a second top surface extending along a shorter edge of the second support surface and a shorter edge of the second rear surface, and a second side surface extending along a longer edge of the second support surface and a longer edge of the second rear surface; and a second plurality of LED chips (3; 14) disposed on the second support surface, each LED chip of the second plurality of LED chips having a second substrate, a second N-type semiconductor layer, a second active layer and a second P-type semiconductor layer, the second substrate being arranged between the second N-type semiconductor layer and the second transparent substrate, that the first side surface and the second side surface point toward the hole but are not in contact with the hole in a top view of the supporting structure, and that the first support surface and the second support surface face different directions. a first rear surface opposite to the first support surface, a first top surface extending along a shorter edge of the first support surface and a shorter edge of the first rear surface, and a first side surface extending along a longer edge of the first support surface and a longer edge of the first rear surface; and a first plurality of LED chips (3; 14) disposed on the first support surface, each LED chip of the first plurality of LED chips having a first substrate, a first N-type semiconductor layer, a first active layer and a first P-type semiconductor layer, first substrate being arranged between the first N-type semiconductor layer and the first transparent substrate, that the second light emitting element comprises: a second transparent substrate having a second support surface, a second rear surface opposite to the second support surface, a second top surface extending along a shorter edge of the second support surface and a shorter edge of the second rear surface, and a second side surface extending along a longer edge of the second support surface and a longer edge of the second rear surface; and a second plurality of LED chips (3; 14) disposed on the second support surface, each LED chip of the second plurality of LED chips having a second substrate, a second N-type semiconductor layer, a second active layer and a second P-type semiconductor layer, the second substrate being arranged between the second N-type semiconductor layer and the second transparent substrate, that the first side surface and the second side surface point toward the hole but are not in contact with the hole in a top view of the supporting structure, and that the first support surface and the second support surface face different directions. a second transparent substrate having a second support surface, a second rear surface opposite to the second support surface, a second top surface extending along a shorter edge of the second support surface and a shorter edge of the second rear surface, and a second side surface extending along a longer edge of the second support surface and a longer edge of the second rear surface; and a second plurality of LED chips (3; 14) disposed on the second support surface, each LED chip of the second plurality of LED chips having a second substrate, a second N-type semiconductor layer, a second active layer and a second P-type semiconductor layer, the second substrate being arranged between the second N-type semiconductor layer and the second transparent substrate, that the first side surface and the second side surface point toward the hole but are not in contact with the hole in a top view of the supporting structure, and that the first support surface and the second support surface face different directions.