A light emitter/sensor unit for a display, the light emitter/sensor unit comprising: a thin-film photodiode detector, TFPD, comprising a film with an upper side and a lower side, the film being configured to absorb light and to convert absorbed light into a current; a first thin-film light-emitting diode, TFLED, comprising a film with an upper side and a lower side, the film being configured to convert an electrical current into light; backplane voltage regulating circuitry comprising first and second TFPD contact surfaces, a first TFLED contact surface, and transistors, wherein the transistors are configured to set an electrical potential of the first TFLED contact surface and to either set electrical potentials of the two TFPD contact surfaces (31, 32) or to measure a potential difference between the two TFPD contact surfaces (31, 32); wherein the lower side of the film of the first TFLED is electrically connected to the first TFLED contact surface, and wherein the lower side of the film of the TFPD is electrically connected to the first TFPD contact surface and the upper side of the film of the TFPD is electrically connected to the second TFPD contact surface; characterized in that the light emitter/sensor unit further comprises: a bottom TFPD contact that protrudes from the first TFPD contact surface and electrically connects the first TFPD contact surface with the lower side of the film of the TFPD; and a top TFPD contact structure comprising a lower contact part that protrudes from the second TFPD contact surface and an upper contact part, that extends laterally from the lower contact part to a position above the upper side of the film of the TFPD and connects with the upper side of the film of the TFPD, thereby electrically connecting the upper side of the film of the TFPD to the second TFPD contact surface via the upper and lower contact parts. a thin-film photodiode detector, TFPD, comprising a film with an upper side and a lower side, the film being configured to absorb light and to convert absorbed light into a current; a first thin-film light-emitting diode, TFLED, comprising a film with an upper side and a lower side, the film being configured to convert an electrical current into light; backplane voltage regulating circuitry comprising first and second TFPD contact surfaces, a first TFLED contact surface, and transistors, wherein the transistors are configured to set an electrical potential of the first TFLED contact surface and to either set electrical potentials of the two TFPD contact surfaces (31, 32) or to measure a potential difference between the two TFPD contact surfaces (31, 32); wherein the lower side of the film of the first TFLED is electrically connected to the first TFLED contact surface, and wherein the lower side of the film of the TFPD is electrically connected to the first TFPD contact surface and the upper side of the film of the TFPD is electrically connected to the second TFPD contact surface; characterized in that the light emitter/sensor unit further comprises: a bottom TFPD contact that protrudes from the first TFPD contact surface and electrically connects the first TFPD contact surface with the lower side of the film of the TFPD; and a top TFPD contact structure comprising a lower contact part that protrudes from the second TFPD contact surface and an upper contact part, that extends laterally from the lower contact part to a position above the upper side of the film of the TFPD and connects with the upper side of the film of the TFPD, thereby electrically connecting the upper side of the film of the TFPD to the second TFPD contact surface via the upper and lower contact parts. a bottom TFPD contact that protrudes from the first TFPD contact surface and electrically connects the first TFPD contact surface with the lower side of the film of the TFPD; and a top TFPD contact structure comprising a lower contact part that protrudes from the second TFPD contact surface and an upper contact part, that extends laterally from the lower contact part to a position above the upper side of the film of the TFPD and connects with the upper side of the film of the TFPD, thereby electrically connecting the upper side of the film of the TFPD to the second TFPD contact surface via the upper and lower contact parts.