Reflective display panel and method for manufacturing such a display panel

1. A reflective display panel ( 9 ), comprising

a plurality of pixels, each pixel having a modulative portion controllable between light-modulation states, and a non-modulative portion, and

a redirection sheet having a plurality of redirecting structures each being configured to redirect ambient light incident thereon towards an adjacent modulative portion.

2. The reflective display panel ( 9 ) according to claim 1 , wherein the redirection sheet ( 14 ) comprises a first set of redirecting structures ( 19 , 20 ) extending essentially parallel in a plane defined by the redirection sheet ( 14 ).

3. The reflective display panel ( 9 ) according to claim 2 , wherein the redirection sheet ( 14 ) further comprises a second set of essentially parallel redirecting structures having a different direction of extension than the first set of redirecting structures ( 19 , 20 ) in the plane defined by the redirection sheet ( 14 ).

4. The reflective display panel ( 9 ) according to claim 1 , wherein each of the redirecting structures ( 19 , 20 ) is provided as an indentation on a first face of the redirection sheet ( 14 ), and the redirection sheet ( 14 ) is arranged in such a way that the ambient light is incident on a second face thereof opposing the first face.

5. The reflective display panel ( 9 ) according to claim 4 , wherein the indentation ( 19 ) contains a material ( 21 ) having a lower refractive index than the redirection sheet ( 14 ).

6. The reflective display panel ( 9 ) according to claim 4 , wherein the indentation ( 20 ) contains a reflective material ( 24 ).

7. The reflective display panel ( 9 ) according to claim 4 , wherein the indentation ( 19 , 20 ) has an essentially V-shaped cross-section.

8. The reflective display panel ( 9 ) according to claim 7 , wherein an opening angle (θ o ) of the V-shaped cross-section is smaller than 150°.

9. The reflective display panel according to claim 1 , further comprising a covering sheet arranged to cover the redirection sheet ( 14 ), the covering sheet having a refractive index which is substantially equal to that of the redirection sheet ( 14 ).

10. The reflective display panel according to claim 1 , wherein each pixel comprises a liquid crystal layer and a pair of electrodes arranged in such a way that a modulative portion of the liquid crystal layer is controllable between light-modulation states through application of a voltage between the electrodes.

11. The reflective display panel according to claim 1 , wherein each pixel comprises two immiscible fluids having different optical properties, and a pair or electrodes for controllably moving the fluids in relation to each other through application of a voltage between the electrodes.

12. The reflective display panel according to claim 1 , wherein each pixel comprises a fluid and a plurality of charged particles suspended therein, and a pair or electrodes for controllably moving the plurality of charged particles through application of a voltage between the electrodes.

13. A method for manufacturing a reflective display panel ( 9 ), the method comprising the steps of:

providing ( 601 ) a reflective display panel comprising a plurality of pixels ( 10 , 11 a - b ), each having a modulative portion ( 15 , 16 a - b ) which is controllable between light-modulation states, and a non-modulative portion ( 17 , 18 ), and

attaching, to the reflective display panel, a redirection sheet ( 14 ) having a plurality of redirecting structures ( 19 , 20 ) configured to redirect ambient light incident thereon towards intermediate portions of the redirection sheet ( 14 ), in such a way that each of the redirecting structures ( 19 , 20 ) is essentially aligned with a corresponding one of the non-modulative portions ( 17 , 18 ).

14. The method according to claim 13 , wherein the step of attaching comprises the steps of:

aligning the redirecting structures ( 19 , 20 ) with corresponding non-modulative portions ( 17 , 18 ) in the display panel, and

fixing ( 605 ) the redirection sheet ( 14 ) to the display panel.

15. The method according to claim 14 , wherein the step of aligning comprises the steps of:

monitoring ( 602 ) a reflection of the display panel, and

stretching ( 604 ) the redirection sheet ( 14 ) such that the evaluation indicates a correct alignment.

16. The method according to claim 13 , wherein the redirection sheet ( 14 ) is applied in a reel-to-reel process.

17. A method for manufacturing a reflective display panel, comprising the steps of:

providing ( 1001 ) a cover sheet ( 30 ) comprising a photo-imageable pixel-defining layer ( 31 ), and a redirection layer ( 14 ) having a plurality of redirecting structures ( 19 , 20 ) configured to redirect light incident thereon towards intermediate portions of the pixel-defining layer ( 31 ), and

irradiating ( 1002 ) the cover sheet ( 30 ) from a redirection layer ( 14 ) side thereof by means of a light-source adapted to enable patterning of the photoimageable pixel-defining layer ( 31 ), thereby leaving portions ( 35 , 36 ) of the pixel-defining layer corresponding to the redirecting structures ( 19 , 20 ) essentially unexposed, while exposing remaining portions thereof,

developing the pixel-defining layer ( 31 ), thereby forming a pixel-defining wall structure ( 35 , 36 ) comprising a plurality of walled-in pixel areas,

providing ( 1004 ) a light-modulative member ( 42 ) within each of the walled-in pixel areas, and

providing ( 1005 ), on a pixel-defining layer ( 31 ) side of the cover sheet ( 30 ), a display base carrier ( 43 ).

18. The method according to claim 17 , wherein the pixel-defining layer ( 31 ) comprises a positive photoresist ( 33 ).

19. The method according to claim 17 , wherein the display base carrier ( 43 ) comprises an electrode pattern ( 44 , 45 , 46 ), and the step of providing ( 1005 ) the display base carrier comprises the steps of:

aligning the display base carrier ( 43 ) to the cover sheet ( 30 ) in such a way that an electrode pair ( 38 , 39 , 46 ) is provided for each of the pixels, and

attaching the display base carrier ( 43 ) to the cover sheet ( 30 ).

20. The method according to claim 17 further comprising the step of forming ( 1003 ), for each pixel, a conductive layer ( 38 , 39 ) on at least a portion of the pixel-defining wall structure ( 35 , 36 ).