Colour Active Matrix Displays

• US 20080212000A1
• Filed: 05/16/2006
• Published: 09/04/2008
• Est. Priority Date: 05/17/2005
• Status: Active Grant

• Current Assignee: Hydis Technologies Co Ltd (E Ink Holdings Incorporated)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Fish, David A., Childs, Mark J., French, Ian D., Hector, Jason R.
• Granted Patent: US 7,773,176 B2
• Time in Patent Office: Days
• US Class Current: 349/106
• CPC Class Codes: G02F 1/133305 Flexible substrates, e.g. plastics, organic film
• CPC Class Codes: G02F 1/133516 Methods for their manufacture, e.g. printing, electro-deposition or photolithography
• CPC Class Codes: G02F 1/133567 on the back side
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: H01L 27/1214 comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• CPC Class Codes: H01L 27/1266 the substrate on which the devices are formed not being the final device substrate, e.g. using a temporary substrate
• CPC Class Codes: H10K 59/38 comprising colour filters or colour changing media [CCM]

Abstract

A method of manufacturing a colour active matrix display device comprises forming islands over a rigid carrier substrate, forming a plastic substrate over the rigid carrier substrate, forming an array of pixel circuits over the plastic substrate and forming a display layer over the array of pixel circuits. The rigid carrier substrate is then released from the plastic substrate and the plastic substrate then has channels defined by the islands. These are filled to define colour filter portions. The formation of a plastic substrate on a rigid carrier, with the use of a subsequent lift off process, enables the circuit arrays to be made on very thin plastic sheets. The colour filters can then be made on the outside of the LC cell. Depressions are formed in the plastic substrate registered to the circuit array, and these are filled in with colour filter material, for example by ink jet printing.

Claims

1. A method of manufacturing a colour active matrix display device, comprising:

forming islands (62) over a rigid carrier substrate (60);

forming a plastic substrate (42,66) over the rigid carrier substrate;

forming an array of pixel circuits (46,72) over the plastic substrate;

forming a display layer over the array of pixel circuits (46,72);

releasing the rigid carrier substrate (60) from the plastic substrate after forming the display layer, the plastic substrate (42,66) having channels (56) defined by the islands; and

filling the channels to define colour filter portions (55).

2. A method as claimed in claim 1, wherein filling the channels comprises printing colour filters (55) into the channels.

3. A method as claimed in claim 2, wherein the printing comprises ink jet printing.

4. A method as claimed in claim 1, wherein the rigid carrier substrate (60) comprises a glass substrate.

5. A method as claimed in claim 1, further comprising forming a release layer (64) between the plastic substrate (66) and the rigid carrier substrate (60).

6. A method as claimed in claim 1, wherein each pixel circuit comprises at least a thin film transistor (72).

7. A method as claimed in claim 6, wherein each thin film transistor (72) comprises an amorphous silicon TFT.

8. A method as claimed in claim 1, wherein the release is by a laser process.

9. A method as claimed in claim 1, further comprising adding a polariser (58) to the plastic substrate.

10. A method as claimed in claim 1, further comprising manufacturing a second substrate arrangement (48), and wherein forming a display layer over the array of pixel circuits comprises mounting the first (40) and second (48) substrate arrangements with electro-optic material sandwiched therebetween, the active matrix display device thereby comprising first and second substrates with the electro-optic material sandwiched therebetween.

11. A method as claimed in claim 10, wherein manufacturing the second substrate arrangement (48) comprises providing a second rigid carrier substrate (76), and a second plastic substrate (49) over the second rigid carrier substrate.

12. A method as claimed in claim 11, wherein the second rigid carrier substrate (76) comprises a glass substrate.

13. A method as claimed in claim 11, further comprising a second release layer (78) between the second plastic substrate (49) and the second rigid carrier substrate (76).

14. A method as claimed in claim 11, further comprising releasing the second rigid carrier substrate (76) from the second plastic substrate (49).

15. A method as claimed in claim 14, wherein the release of the second rigid carrier substrate from the second plastic substrate is by a laser process.

16. A method as claimed in claim 14, further comprising adding a polariser (80) to the second plastic substrate.

17. A method as claimed in claim 10, wherein manufacturing the second substrate arrangement further comprises providing a top conductive layer (50).

18. A method as claimed in claim 17, wherein the top conductive layer (50) comprises an ITO layer.

19. A method as claimed in claim 1, wherein forming the or each plastic substrate comprises applying a plastic coating to a rigid carrier substrate using a spin-on process.

20. A method as claimed in claim 1, wherein the or each plastic substrate comprises parylene.

21. A colour display device, comprising:

a plastic substrate (42);

an array of thin film pixel circuits (46,72) deposited over the plastic substrate (42);

a display layer over the array of pixel circuits; and

an array of colour filter portions (55) provided in channels (56) on the opposite side of the plastic substrate (42) to the array of thin film pixel circuits (46,72), the channels being defined by a support structure (60,62) which supports the plastic substrate during the deposition of the thin film pixel circuits, and which is removed to enable provision of the colour filter portions (55).

22. A device as claimed in claim 21, wherein the maximum thickness of the plastic substrate (42) is less than 50 μ

m.

23. A device as claimed in claim 21, further comprising a second substrate arrangement (48), and wherein the display layer comprises electro-optic material sandwiched between the first and second substrates (40,48).

24. A device as claimed in claim 23, wherein the electro-optic material comprises LC material.