A display apparatus comprising: a display; a plurality of light emitting elements (10-1, 10-2, 10-3); a plurality of light receiving elements; and a processor configured to: based on a touch by a touch pen on the display being sensed, identify a touch position of the touch pen, characterized in that the processor is further configured to: control a first light emitting element among the plurality of light emitting elements to emit first light of a first wavelength and a second light emitting element among the plurality of light emitting elements to emit second light of a second wavelength different from the first wavelength based on the identified touch position, and identify a first intensity of the first light received by at least one light receiving element among the plurality of light receiving elements, identify a second intensity of the second light received by the at least one light receiving element, identify a pen color of the touch pen based on the first intensity and the second intensity, and control the display to display a touch trajectory based on the sensed touch of the touch pen on the display in the identified pen color of the touch pen; and the display apparatus further comprising: a bezel disposed at an outer region of the display; and a guide member formed to protrude at one region of the bezel, wherein the plurality of light receiving elements is supported by the guide member and disposed to be inclined toward a direction of a screen of the display. a display; a plurality of light emitting elements (10-1, 10-2, 10-3); a plurality of light receiving elements; and a processor configured to: based on a touch by a touch pen on the display being sensed, identify a touch position of the touch pen, characterized in that the processor is further configured to: control a first light emitting element among the plurality of light emitting elements to emit first light of a first wavelength and a second light emitting element among the plurality of light emitting elements to emit second light of a second wavelength different from the first wavelength based on the identified touch position, and identify a first intensity of the first light received by at least one light receiving element among the plurality of light receiving elements, identify a second intensity of the second light received by the at least one light receiving element, identify a pen color of the touch pen based on the first intensity and the second intensity, and control the display to display a touch trajectory based on the sensed touch of the touch pen on the display in the identified pen color of the touch pen; and the display apparatus further comprising: a bezel disposed at an outer region of the display; and a guide member formed to protrude at one region of the bezel, wherein the plurality of light receiving elements is supported by the guide member and disposed to be inclined toward a direction of a screen of the display. based on a touch by a touch pen on the display being sensed, identify a touch position of the touch pen, characterized in that the processor is further configured to: control a first light emitting element among the plurality of light emitting elements to emit first light of a first wavelength and a second light emitting element among the plurality of light emitting elements to emit second light of a second wavelength different from the first wavelength based on the identified touch position, and identify a first intensity of the first light received by at least one light receiving element among the plurality of light receiving elements, identify a second intensity of the second light received by the at least one light receiving element, identify a pen color of the touch pen based on the first intensity and the second intensity, and control the display to display a touch trajectory based on the sensed touch of the touch pen on the display in the identified pen color of the touch pen; and the display apparatus further comprising: a bezel disposed at an outer region of the display; and a guide member formed to protrude at one region of the bezel, wherein the plurality of light receiving elements is supported by the guide member and disposed to be inclined toward a direction of a screen of the display. control a first light emitting element among the plurality of light emitting elements to emit first light of a first wavelength and a second light emitting element among the plurality of light emitting elements to emit second light of a second wavelength different from the first wavelength based on the identified touch position, and identify a first intensity of the first light received by at least one light receiving element among the plurality of light receiving elements, identify a second intensity of the second light received by the at least one light receiving element, identify a pen color of the touch pen based on the first intensity and the second intensity, and control the display to display a touch trajectory based on the sensed touch of the touch pen on the display in the identified pen color of the touch pen; and the display apparatus further comprising: a bezel disposed at an outer region of the display; and a guide member formed to protrude at one region of the bezel, wherein the plurality of light receiving elements is supported by the guide member and disposed to be inclined toward a direction of a screen of the display. a bezel disposed at an outer region of the display; and a guide member formed to protrude at one region of the bezel, wherein the plurality of light receiving elements is supported by the guide member and disposed to be inclined toward a direction of a screen of the display.