A display device comprising a display area and a peripheral area surrounding the display area, the display device comprising: a lower substrate; a sub-pixel structure in the display area on the lower substrate; an optical filter layer on the sub-pixel structure; a colour filter layer on the optical filter layer; an upper substrate on the colour filter layer; and an alignment structure in the peripheral area on a bottom surface of the upper substrate, the alignment structure comprising a first material that is the same as a material forming the optical filter layer and a second material that is the same as a material forming the colour filter layer, wherein the sub-pixel structure includes first, second, and third sub-pixel structures, and each of the first to third sub-pixel structures includes: a lower electrode disposed on the lower substrate; a light emitting layer disposed on the lower electrode; and an upper electrode disposed on the light emitting layer, and wherein the light emitting layer emits blue light, and is integrally formed in the display area on the lower substrate, and wherein the optical filter layer includes a first quantum dot pattern disposed on the first sub-pixel structure to convert blue light into green light; a scattering pattern disposed on the second sub-pixel structure to transmit the blue light; and a second quantum dot pattern disposed on the third sub-pixel structure to convert the blue light into red light. a lower substrate; a sub-pixel structure in the display area on the lower substrate; an optical filter layer on the sub-pixel structure; a colour filter layer on the optical filter layer; an upper substrate on the colour filter layer; and an alignment structure in the peripheral area on a bottom surface of the upper substrate, the alignment structure comprising a first material that is the same as a material forming the optical filter layer and a second material that is the same as a material forming the colour filter layer, wherein the sub-pixel structure includes first, second, and third sub-pixel structures, and each of the first to third sub-pixel structures includes: a lower electrode disposed on the lower substrate; a light emitting layer disposed on the lower electrode; and an upper electrode disposed on the light emitting layer, and wherein the light emitting layer emits blue light, and is integrally formed in the display area on the lower substrate, and wherein the optical filter layer includes a first quantum dot pattern disposed on the first sub-pixel structure to convert blue light into green light; a scattering pattern disposed on the second sub-pixel structure to transmit the blue light; and a second quantum dot pattern disposed on the third sub-pixel structure to convert the blue light into red light. a lower electrode disposed on the lower substrate; a light emitting layer disposed on the lower electrode; and an upper electrode disposed on the light emitting layer, and wherein the light emitting layer emits blue light, and is integrally formed in the display area on the lower substrate, and wherein the optical filter layer includes a first quantum dot pattern disposed on the first sub-pixel structure to convert blue light into green light; a scattering pattern disposed on the second sub-pixel structure to transmit the blue light; and a second quantum dot pattern disposed on the third sub-pixel structure to convert the blue light into red light.