A display device comprising: a display panel that comprises a display area comprising a first optical area comprising a plurality of light emitting areas and a plurality of first transmission areas, and a normal area located outside of the first optical area and comprising a plurality of light emitting areas, and a non-display area, and that comprises a plurality of signal lines, wherein the plurality of signal lines comprise: a first horizontal line comprising a first optical horizontal line portion (HL1_O1) disposed in the first optical area and a non-optical horizontal line portion (HL1_N) disposed in the normal area; and a second horizontal line disposed in the normal area without being disposed in the first optical area, wherein the first optical horizontal line portion (HL1_O1) of the first horizontal line comprises a first outer horizontal line portion (HL1_OUT1) disposed in an outer area within the first optical area, and a first inner horizontal line portion (HL1_IN1) located inside of the first outer horizontal line portion (HL1_OUT1) in the first optical area, characterised in that a length per unit area of the first outer horizontal line portion (HL1_OUT1) is greater than a length per unit area of the first inner horizontal line portion (HL1_IN1), or greater than a length per unit area of the non-optical horizontal line portion (HL1_N), or a width of all or a portion of the first horizontal line is smaller than a width of the second horizontal line, and wherein the first inner horizontal line portion (HL1_IN1) is disposed to avoid the plurality of first transmission areas in the first optical area, and the first outer horizontal line portion (HL1_OUT1) is disposed in at least one first transmission area disposed in the outer area within the first optical area among the plurality of first transmission areas in the first optical area. a display panel that comprises a display area comprising a first optical area comprising a plurality of light emitting areas and a plurality of first transmission areas, and a normal area located outside of the first optical area and comprising a plurality of light emitting areas, and a non-display area, and that comprises a plurality of signal lines, wherein the plurality of signal lines comprise: a first horizontal line comprising a first optical horizontal line portion (HL1_O1) disposed in the first optical area and a non-optical horizontal line portion (HL1_N) disposed in the normal area; and a second horizontal line disposed in the normal area without being disposed in the first optical area, wherein the first optical horizontal line portion (HL1_O1) of the first horizontal line comprises a first outer horizontal line portion (HL1_OUT1) disposed in an outer area within the first optical area, and a first inner horizontal line portion (HL1_IN1) located inside of the first outer horizontal line portion (HL1_OUT1) in the first optical area, characterised in that a length per unit area of the first outer horizontal line portion (HL1_OUT1) is greater than a length per unit area of the first inner horizontal line portion (HL1_IN1), or greater than a length per unit area of the non-optical horizontal line portion (HL1_N), or a width of all or a portion of the first horizontal line is smaller than a width of the second horizontal line, and wherein the first inner horizontal line portion (HL1_IN1) is disposed to avoid the plurality of first transmission areas in the first optical area, and the first outer horizontal line portion (HL1_OUT1) is disposed in at least one first transmission area disposed in the outer area within the first optical area among the plurality of first transmission areas in the first optical area.