A display device comprising: a plurality of LEDs configured to emit light in the direction of an optical axis; a wavelength conversion member adjacent to the plurality of LEDs for converting the wavelength of light emitted from the LEDS; a heat transfer part between the plurality of LEDs and the wavelength conversion member; a heat dissipation part connected to the heat transfer part; and a display panel to which light output from the wavelength conversion member is incident, wherein the wavelength conversion member comprises: an incident surface opposite to the plurality of LEDs; an exit surface opposite to the incident surface; and a first inclined surface extending from the incident surface to the exit surface, wherein the first inclined surface is inclined with respect to the incident surface of the wavelength conversion member and with respect to a surface which is perpendicular to the optical axis, wherein the heat transfer part is transparent and wherein the heat transfer part is disposed on the incident surface and on the exit surface of the wavelength conversion member covers the first inclined surface of the wavelength conversion member, whereby the heat transfer part is in contact with the wavelength conversion member, and further characterised in that the display device comprises a reflective sheet; a light guide plate on the reflective sheet, comprising an incident surface facing the plurality of LEDs; a plurality of optical sheets on the light guide plate; and the wavelerth conversion member is interposed between the LEDS and the light guide plate, and in that the wavelength conversion member comprises a second inclined surface, wherein the second inclined surface is inclined with respect to the incident surface of the wavelength conversion member and with respect to a surface which is perpendicular to the optical axis, wherein the heat transfer part also covers the second inclined surface. a plurality of LEDs configured to emit light in the direction of an optical axis; a wavelength conversion member adjacent to the plurality of LEDs for converting the wavelength of light emitted from the LEDS; a heat transfer part between the plurality of LEDs and the wavelength conversion member; a heat dissipation part connected to the heat transfer part; and a display panel to which light output from the wavelength conversion member is incident, wherein the wavelength conversion member comprises: an incident surface opposite to the plurality of LEDs; an exit surface opposite to the incident surface; and a first inclined surface extending from the incident surface to the exit surface, wherein the first inclined surface is inclined with respect to the incident surface of the wavelength conversion member and with respect to a surface which is perpendicular to the optical axis, wherein the heat transfer part is transparent and wherein the heat transfer part is disposed on the incident surface and on the exit surface of the wavelength conversion member covers the first inclined surface of the wavelength conversion member, whereby the heat transfer part is in contact with the wavelength conversion member, and further characterised in that the display device comprises a reflective sheet; a light guide plate on the reflective sheet, comprising an incident surface facing the plurality of LEDs; a plurality of optical sheets on the light guide plate; and the wavelerth conversion member is interposed between the LEDS and the light guide plate, and in that the wavelength conversion member comprises a second inclined surface, wherein the second inclined surface is inclined with respect to the incident surface of the wavelength conversion member and with respect to a surface which is perpendicular to the optical axis, wherein the heat transfer part also covers the second inclined surface. an incident surface opposite to the plurality of LEDs; an exit surface opposite to the incident surface; and a first inclined surface extending from the incident surface to the exit surface, wherein the first inclined surface is inclined with respect to the incident surface of the wavelength conversion member and with respect to a surface which is perpendicular to the optical axis, wherein the heat transfer part is transparent and wherein the heat transfer part is disposed on the incident surface and on the exit surface of the wavelength conversion member covers the first inclined surface of the wavelength conversion member, whereby the heat transfer part is in contact with the wavelength conversion member, and further characterised in that the display device comprises a reflective sheet; a light guide plate on the reflective sheet, comprising an incident surface facing the plurality of LEDs; a plurality of optical sheets on the light guide plate; and the wavelerth conversion member is interposed between the LEDS and the light guide plate, and in that the wavelength conversion member comprises a second inclined surface, wherein the second inclined surface is inclined with respect to the incident surface of the wavelength conversion member and with respect to a surface which is perpendicular to the optical axis, wherein the heat transfer part also covers the second inclined surface. a reflective sheet; a light guide plate on the reflective sheet, comprising an incident surface facing the plurality of LEDs; a plurality of optical sheets on the light guide plate;