A luminous unit (1) for an optical recording device (13) comprising a light source (2) for generating radiation and a partly reflective element, which is disposed downstream of the light source (2) in a main emission direction (H) and subdivides a space into a first half-space facing the light source (2) and a second half-space remote from the light source (2), wherein the partly reflective element at least partly transmits the radiation coming from the light source (2) from the first half-space and at least partly reflects the external radiation coming from an opposite direction from the second half-space.