Distortion tolerant pixel design
View Patent ↗A method of manufacturing a flexible display is provided, which includes depositing a first layer comprising a plurality of thin film transistors (TFTs) on a flexible substrate and depositing a second layer comprising a plurality of pixel electrodes above the first layer with each pixel electrode connected to a respective TFT via a respective via connector between the first and second layers. A display medium responsive to signals on the pixel electrode can be deposited on the second layer for displaying an image on the second layer. A third layer comprising color filters for filtering an image displayed on the display medium can be aligned to the second layer. The third layer can be deposited and aligned on the second layer such that each color filter is substantially aligned to a respective pixel electrode to compensate for distortions in the first layer caused by distortions in the flexible substrate.
1. A method of manufacturing a flexible display comprising:
depositing a first layer comprising a plurality of thin film transistors (TFTs) on a flexible substrate;
depositing a second layer above said first layer, said second layer comprising a plurality of pixel electrodes, each of said pixel electrodes being connected to a respective TFT via a respective via connector between said first and second layers;
depositing a display medium for displaying an image on said second layer, said display medium being responsive to signals on said pixel electrode;
aligning a third layer to said second layer, said third layer comprising a plurality of colour filters for filtering an image displayed on said display medium; and
depositing said third layer on said second layer, wherein said third layer is aligned to said second layer such that each of said colour filters is substantially aligned to a respective pixel electrode, and wherein said alignment compensates for distortions in said first layer caused by distortions in said flexible substrate.
2. A method according to claim 1 , wherein depositing a second layer comprises:
depositing a conductive material on said first layer; and
patterning said conductive material to define said plurality of pixel electrodes, and
wherein said pixel electrodes are shaped to enable said pixel electrodes and said TFTs to be displaced laterally from one another, said displacement being caused by distortions in said flexible substrate.
3. A method according to claim 2 , wherein a maximum lateral displacement is less than half of a difference between a dimension of said electrode and a diameter of said via connector.
4. A method according to claim 1 , wherein depositing a third layer comprises:
depositing a filtering material on said display medium; and
patterning said filtering material to define said plurality of colour filters, each of said colour filters being substantially aligned to a respective pixel electrode.
5. A method according to claim 2 , wherein patterning comprises performing a step and repeat exposure procedure comprising exposing a first area of said layer to a light source to define a pattern, and translating said substrate from a first position at which said first area is exposable to a second position at which a second area of said layer is exposable.
6. A method according to claim 5 , wherein a distance between said first position and said second position is an integer multiple of a pitch of said pixel electrodes.
7. A method according to claim 5 , wherein a distance between said first and said second position is selected to correct for distortion in said first layer caused by distortion in said flexible substrate.
8. A method according to claim 5 , wherein said light source is a laser and wherein said material is laser ablated.
9. A method according to claim 5 , wherein said exposure comprises a photolithographic process.
10. A method according to claim 2 , wherein said material is deposited and patterned substantially at the same time by printing said material in a pattern onto said layer.
11. A method according to claim 1 , wherein aligning comprises aligning features in said third layer to corresponding features in said second layer.
12. A method according to claim 11 , wherein said features include layer markers disposed in one or more corners of said layer.
13. A method according to claim 1 , wherein aligning comprises measuring and storing positioning data representing a position of said display during said deposition of said second layer; and controlling a position of said display during said depositing of said third layer using said data.
14. A method according to claim 1 , wherein said display medium comprises an electrophoretic display medium.
15. A method according to claim 1 , wherein said display medium comprises a liquid crystal medium.
16. A method according to claim 1 , wherein said substrate comprises polyethyleneterephtalate (PET) or polyethylenenaphtalene (PEN).
17. A method according to claim 1 , wherein said TFT comprises an organic semiconductor.
18. A method according to claim 17 , wherein said organic semiconductor is a solution-processed organic semiconductor.