A display device, comprising: a substrate having a plurality of active elements and a bonding pad; a light-emitting unit disposed on the substrate, comprising: a light-emitting part having a first surface and a second surface opposite to the first surface; a connective part adjacent to the second surface of the light-emitting part, comprising; a conductive pad adjacent to the second surface of the light-emitting part; and a bonding layer disposed on the conductive pad and electrically connected to the bonding pad of the substrate, wherein the bonding layer has a third surface adjacent to the conductive pad and a fourth surface adjacent to the bonding pad, and wherein the bonding layer has a first material layer and a second material layer; and a protective part surrounding the light-emitting part and the connective part; and a transparent structure disposed on the first surface of the light-emitting part, wherein the refractive index of the transparent structure decreases parallel to a first direction from the second surface to the first surface of the light-emitting part; characterized in that the first material layer comprises a first component, the second material layer comprises a second component distributed in the bonding layer non-uniformly, the second component has a first concentration at the third surface of the bonding layer, a second concentration at the fourth surface of the bonding layer and a third concentration between the first surface of the bonding layer and the second surface of the bonding layer, and the third concentration is smaller than the first concentration and the second concentration. a substrate having a plurality of active elements and a bonding pad; a light-emitting unit disposed on the substrate, comprising: a light-emitting part having a first surface and a second surface opposite to the first surface; a connective part adjacent to the second surface of the light-emitting part, comprising; a conductive pad adjacent to the second surface of the light-emitting part; and a bonding layer disposed on the conductive pad and electrically connected to the bonding pad of the substrate, wherein the bonding layer has a third surface adjacent to the conductive pad and a fourth surface adjacent to the bonding pad, and wherein the bonding layer has a first material layer and a second material layer; and a protective part surrounding the light-emitting part and the connective part; and a transparent structure disposed on the first surface of the light-emitting part, wherein the refractive index of the transparent structure decreases parallel to a first direction from the second surface to the first surface of the light-emitting part; characterized in that the first material layer comprises a first component, the second material layer comprises a second component distributed in the bonding layer non-uniformly, the second component has a first concentration at the third surface of the bonding layer, a second concentration at the fourth surface of the bonding layer and a third concentration between the first surface of the bonding layer and the second surface of the bonding layer, and the third concentration is smaller than the first concentration and the second concentration. a light-emitting part having a first surface and a second surface opposite to the first surface; a connective part adjacent to the second surface of the light-emitting part, comprising; a conductive pad adjacent to the second surface of the light-emitting part; and a bonding layer disposed on the conductive pad and electrically connected to the bonding pad of the substrate, wherein the bonding layer has a third surface adjacent to the conductive pad and a fourth surface adjacent to the bonding pad, and wherein the bonding layer has a first material layer and a second material layer; and a protective part surrounding the light-emitting part and the connective part; and a transparent structure disposed on the first surface of the light-emitting part, wherein the refractive index of the transparent structure decreases parallel to a first direction from the second surface to the first surface of the light-emitting part; characterized in that the first material layer comprises a first component, the second material layer comprises a second component distributed in the bonding layer non-uniformly, the second component has a first concentration at the third surface of the bonding layer, a second concentration at the fourth surface of the bonding layer and a third concentration between the first surface of the bonding layer and the second surface of the bonding layer, and the third concentration is smaller than the first concentration and the second concentration.