Continuous photolithographic fabrication process for producing seamless microstructures used in electro-optic displays and light modulating films

Abstract

A roll-to-roll method for manufacturing seamless microstructures is provided, comprising the following steps: (a) continuously forming a laminated structure including a photomask film superimposed on a substrate, having a photosensitive material therebetween, the photomask film including a pattern of light-transmitting regions and light-shielding regions; (b) irradiating the photomask film of the laminated structure formed in step (a) such that light passes through the light-transmitting regions of the photomask film to cure portions of the photosensitive material exposed by the light-transmitting regions, while the remaining portions of the photosensitive material covered by the light-shielding regions remain uncured; (c) peeling the photomask film from the photosensitive material selectively cured in step (b); and (d) removing the uncured portions of the photosensitive material to form a microstructure on the substrate from the cured portions of the photosensitive material.

Claims

1. A method for fabricating a seamless microstructure by roller to roller, comprising the following steps: (a) continuously forming a laminated structure comprising a first photomask film superimposed on a second photomask film, wherein a photosensitive material is disposed therebetween, the first photomask film comprising a pattern of a light-transmitting area and a light-shielding area disposed on a substrate, and the second photomask film comprising a pattern of a light-transmitting area and a light-shielding area disposed on a release liner. (b) Irradiating the first photomask film of the laminated structure formed in step (a) with light from a first light source to expose the portions of the photosensitive material covered by the light-transmitting area of ​​the first photomask film to the light, while keeping the remaining portions of the photosensitive material covered by the light-shielding area of ​​the first photomask film from being exposed to the light; and irradiating the second photomask film of the laminated structure formed in step (a) with light from a second light source to expose the portions of the photosensitive material covered by the light-transmitting area of ​​the second photomask film to the light, while keeping the remaining portions of the photosensitive material covered by the light-shielding area of ​​the second photomask film from being exposed to the light; (c) peeling the release liner from the photosensitive material selectively irradiated in step (b); and (d) selectively removing the portions of the photosensitive material exposed to the light from the first light source and the second light source, or selectively removing the portions of the photosensitive material not exposed to the light from the first light source and the second light source, to form a microstructure on the first photomask film.

2. The method of claim 1, wherein in step (b), the light-blocking area of ​​the first photomask film or the second photomask film is transparent to visible light, but the light used is light-blocking.

3. The method of claim 1, wherein step (d) comprises selectively removing portions of the photosensitive material exposed to the light to form a microstructure on the first photomask film.

4. The method of claim 1, wherein step (d) comprises selectively removing portions of the photosensitive material not exposed to the light to form a microstructure on the first photomask film.

5. The method of claim 1, wherein in step (b), portions of the photosensitive material exposed to light from the first light source or the second light source are cured by the light, while the remaining portions of the photosensitive material remain uncured; and wherein in step (d), the uncured portions of the photosensitive material are removed to form the microstructure layer on the first photomask film from the cured portions of the photosensitive material.

6. The method of claim 1, wherein the light from the first light source or the second light source comprises ultraviolet light.

7. The method of claim 1, wherein the photosensitive material comprises a negative ultraviolet-sensitive material.

8. The method of claim 1, wherein the microstructures comprise a cross-linked UV-curable structure.

9. The method of claim 1, wherein step (a) comprises advancing the first photomask film, the second photomask film and the photosensitive material layer between a pair of pressure rollers to form the laminated structure.

10. The method of claim 1, wherein steps (a) and (b) are performed in a multi-coating head production line.

11. The method of claim 1, wherein step (b) is performed concurrently with the transport of the laminated structure.

12. The method of claim 1, wherein the photosensitive material layer is coated on the first photomask film prior to step (a).

13. The method of claim 1, wherein the photosensitive material layer is applied to the first photomask film or the second photomask film using a rod, bar, blade, or stencil coating process prior to step (a).

14. The method of claim 1, wherein the first photomask film laminated in step (a) includes a set of pre-existing microstructures formed thereon.

15. The method of claim 1 further includes, prior to step (a), drawing the first photomask film and the second photomask film from each roller.

16. The method of claim 15, wherein the width of each roller is greater than 1m.

17. The method of claim 1, wherein the microstructures include features having an X / Y dimension resolution of 20 μm to 2000 μm and a Z dimension resolution of 1 μm to 500 μm.

18. The method of claim 1, wherein the first photomask film on which the microstructure layer has been formed has a width greater than one meter.

19. The method of claim 1, wherein the first photomask film on which the microstructure layer has been formed has a length greater than one meter.

20. The method of claim 1, wherein the microstructure fabrication process has a rate greater than 3 meters per minute.

21. The method of claim 1, wherein step (d) comprises introducing the photosensitive material and the first photomask film into a solvent bath to dissolve the portion of the photosensitive material to be removed.

22. The method of claim 1, wherein the microstructure fabrication method produces a seamless roller on which the first photomask film having the microstructure layer is applied.

23. The method of claim 1, wherein the first photomask film comprises a photomask pattern printed on the substrate.

24. The method of claim 23, wherein the photomask pattern faces and is adjacent to the photosensitive material.

25. The method of claim 1, wherein a microstructure layer on the first photomask film is used to construct an electrophoresis apparatus.

26. The method of claim 1, wherein the first photomask film or the second photomask film includes grayscale features to change the intensity of light incident on the photosensitive material to vary the height of the microstructures.

27. A microstructure layer produced on a photomask film by any one of claims 1 to 26.

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