Light exit window having adjustable contrast sensitivity

A method for manufacturing a light generating system comprising a first light generating device and a unit, wherein:

• the first light generating device is configured to provide first device light having a wavelength in the visible wavelength range, the unit comprises in cross-sectional view an open hollow part and a closed hollow part;
• wherein the unit comprises a viewer side;
• wherein relative to the viewer side, the open hollow part is concave, the open hollow part comprises a first wall part;
• wherein the first wall part is diffuse reflective for the first device light, the closed hollow part comprises a chamber wall comprising (a) a second wall part, wherein the second wall part is translucent for the first device light, and (b) a chamber wall part, wherein the chamber wall part is diffuse reflective for the first device light, the unit comprises a wall element comprising the first wall part and the second wall part, the first light generating device is configured in the open hollow part;
• wherein the first light generating device is configured to irradiate (i) at least part of the first wall part and (ii) at least part of the second wall part;
• and the unit and the first light generating device are configured such that first device light does not directly escape from the viewer side;
• and wherein the closed hollow part is configured such that at least part of the first device light entering the closed hollow part via the second wall part also escapes via the second wall part, the method comprising:
• (a) providing a first curved and diffuse reflective element comprising the chamber wall and an extension part that is at least partly conformal with the first wall part, wherein the extension part comprises the first light generating device;
• (b) providing a second curved element comprising the first wall part and the second wall part;
• (c) connecting the first element at an end portion of the chamber wall with the second curved element at an end portion of the second wall part via a clamping mechanism;
• and
• (d) connecting the first element at an end portion of the extension part with the second element at an end portion of the first wall part via a clamping mechanism.