Filament lamp

1. A light generating device comprising:

a light source comprising a light emitting surface, wherein the light source is configured to generate light source light, wherein the light emitting surface is configured in a light chamber;

wherein the light chamber is at least partly defined by a chamber wall, wherein the chamber wall comprises:

(i) a first part, wherein the first part is transmissive for the light source light, wherein the first part has a first reflectance R 1 for the light source light, and wherein the first part has a first part area; and

(ii) one or more second parts, wherein each second part is transmissive for the light source light, has a second reflectance R 2 for the light source light, and wherein the one or more second parts together have a second part area, wherein R 1 -R 2 ≥20%, wherein 65%≤R 1 <100%, wherein the second part area is smaller than the first part area, and wherein 0.005 A 2 /A 1 ≤0.05.

2. The light generating device according to claim 1 , wherein the one or more second parts have the shape of a slit.

3. The light generating device according to claim 1 , wherein 75%≤R 1 <95%.

4. The light generating device according to claim 1 , wherein R 1 -R 2 ≥30%.

5. The light generating device according to claim 1 , 0.005≤A 2 /A 1 ≤0.1.

6. The light generating device according to claim 1 , wherein R 1 -R 2 ≥40%.

7. The light generating device according to claim 1 , comprising 2-6 second parts, wherein the second parts are regularly distributed over the chamber wall, and wherein the light generating device comprises a plurality of solid state light sources configured to generate light source light, wherein the solid state light sources comprise light emitting surfaces configured in the light chamber.

8. The light generating device according to claim 1 , wherein the one or more second parts have a second part width (w 1 ), wherein the second part width is selected from the range of 1 mm≤w 1 ≤5 mm, wherein the one or more second parts have a second part length (L 2 ), wherein the second part width (w 1 ) and the second part length (L 2 ) have a ratio select from the range of w 1 /L 2 ≤0.5.

9. The light generating device according to claim 1 , wherein the first part has a first wall thickness (d 1 ), wherein the one or more second parts have a second wall thickness (d 2 ), wherein the second wall thickness (d 2 ) and first wall thickness (d 1 ) have a wall thickness ratio 0.05≤d 2 /d 1 ≤0.8.

10. The light generating device according to claim 1 , wherein the light chamber has the shape of a light bulb having a chamber length (L 1 ), wherein the one or more second parts have a second part length (L 2 ), wherein the second part length (L 2 ) is at least 5 mm, wherein the second part length (L 2 ) and the chamber length have a ratio selected from the range of 0.5≤L 2 /L 1 ≤1.

11. The light generating device according to claim 1 , wherein the light generating device comprises a lamp base, wherein the light chamber extends from the lamp base.

12. The light generating device according to claim 1 , wherein the second reflectance R 2 is selected from the range of 10%≤R 2 ≤70%.

13. The light generating device according to claim 1 , wherein the second reflectance R 2 is selected from the range of R 2 <20%, wherein the light generating device further comprises a second chamber wall enclosing the chamber wall, wherein the second chamber wall is transmissive for the light source light, and wherein the second chamber wall has a third reflectance R 3 for the light source light, wherein 5%≤R 3 ≤70%.

14. A light generating system comprising (i) the light generating device according to claim 1 , wherein the light generating device is configured to generate device light, and (ii) a control system configured to control one or more lighting parameters of the device light.

15. The light generating system according to claim 14 , wherein the control system is configured to control one or more of color temperature, color point, and luminous flux.