The disclosed embodiments relate to a lighting device (1) comprising an exit window (2) and a light source substrate (3) arranged to carry at least one solid-state light source (4), the at least one light source (4) being arranged to emit light through the exit window (2). The exit window (2) is shaped to allow a front surface of the light source substrate (3) to be brought into physical contact with a surface of the exit window facing the light source substrate (3), and in that the light source substrate (3) is held in physical contact with the exit window (2), thereby enabling thermal contact between the light source substrate (3) and the exit window (2). Since thermal contact between the exit window and the light source substrate is secured, the heat transfer of the lighting device will be improved.