Backlit displays

• US 7,116,308 B1
• Filed: 06/16/1999
• Issued: 10/03/2006
• Est. Priority Date: 06/19/1998
• Status: Expired due to Fees

• Current Assignee: IPIFS Guarantee Corp.
• Original Assignee: Cambridge Display Technology Limited (Sumitomo Chemical Company Limited)
• Inventors: Carter, Julian Charles, Heeks, Stephen Karl
• Primary Examiner(s): Mengistu, Amare
• Application Number:
  US09/719,955
• Time in Patent Office: 2,666 Days
• Field of Search: 345/36, 345/45, 345/76, 345/83, 345/102, 313/504, 313/506, 313/509, 257/40, 257/72, 257/88, 257/89, 257/98
• US Class Current: 345/102
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2310/024 Scrolling of light from the illumination source over the display in combination with the scanning of the display screen
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: G09G 3/342 using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
• CPC Class Codes: G09G 3/3622 using a passive matrix G09G3/3674 - G09G3/3696 take precedence
• CPC Class Codes: H10K 50/85 Arrangements for extracting light from the devices
• CPC Class Codes: H10K 50/852 comprising a resonant cavity structure, e.g. Bragg reflector pair
• CPC Class Codes: H10K 59/50 OLEDs integrated with light modulating elements, e.g. with electrochromic elements, photochromic elements or liquid crystal elements
• CPC Class Codes: H10K 59/876 comprising a resonant cavity structure, e.g. Bragg reflector pair
• CPC Class Codes: H10K 71/135 using ink-jet printing

Abstract

A display device comprising: a light switching unit comprising an array of pixels each operable to vary the transmission of light therethrough; and a backlight comprising a first series of regions of organic light-emissive material having a first emission color and a second series of regions of organic light-emissive material having a second emission color, each region of organic material being located so as to lie behind a plurality of pixels of the array in the viewing direction for backlighting those pixels; and at least one of the regions of organic light-emissive material being formed by a process of ink-jet deposition.

Claims

1. A display device comprising:

a light switching unit comprising an array of pixels each operable to vary the transmission of light therethrough; and

a backlight comprising a first series of regions of organic light-emissive material having a first emission colour and a second series of regions of organic light-emissive material having a second emission colour, each region of organic material being located so as to lie behind a plurality of pixels of the array in the viewing direction for backlighting those pixels; and

at least one of the regions of organic light-emissive material being formed by a process of ink-jet deposition; and

,

a structure for spatially and/or spectrally narrowing light emission from at least one of the regions of light-emissive material, the structure comprising an interference structure, a cavity structure and/or a micro cavity structure.

2. A display device as claimed in claim 1, wherein each region of organic light-emissive material is formed by a process of ink-jet-deposition.

3. A display device as claimed in claim 1, wherein the backlight comprises a third series of regions of organic light-emissive material having a third emission colour.

4. A display device as claimed in claim 3, wherein each region of organic light emissive material having one emission colour is spaced from the next such region by at least regions of organic light-emissive material having both of the other emission colours.

5. A display device as claimed in claim 1, wherein each region of organic light-emissive material is formed by means of ink-jet deposition of material into a groove.

6. A display device as claimed in claim 5, wherein the groove is defined by regions of electrically insulating material.

7. A display device as claimed in claim 1, wherein the backlight comprises electrodes located on either side of the light-emissive material.

8. A display device as claimed in claim 7, wherein at least one of the electrodes is light transmissive.

9. A display device as claimed in claim 7, wherein parts of at least one of the electrodes overlap parts of the insulating material and lie in front of those parts of the insulating material in the viewing direction.

10. A display device as claimed in claim 7, comprising conductive material located in contact with an electrode to lower the resistance across that electrode.

11. A display device as claimed in claim 10, wherein the said conductive material comprises a metal or an alloy.

12. A display device as claimed in claim 10, wherein the said regions of conductive material at least partially overlap the insulating material.

13. A display device as claimed in claim 7, wherein at least one of the electrodes is patterned to permit independent control of each series of light-emissive regions.

14. A display device as claimed in claim 13, wherein only one of the electrodes is patterned to permit independent control of each series of light-emissive regions and the other electrode is common to all the light-emissive regions.

15. A display device as claimed in claim 1, comprising an optical colour filter arranged for receiving and filtering light emitted from at least one of the regions of light-emissive material.

16. A display device as claimed in claim 1, wherein the light switching unit is a liquid crystal unit.

17. A display device as claimed in claim 1, wherein the array of pixels is an orthogonal array.

18. A display device as claimed in claim 1, wherein each region of organic light-emissive material is formed by means of ink-jet deposition of a solution of the organic light-emissive material.

19. A display device as claimed in claim 1, wherein the organic material is a polymer.

20. A display device as claimed in claim 1, wherein the organic material is precursor material.

21. A display device as claimed in claim 1, comprising a display control unit coupled to the light switching unit and the backlight and operable to address synchronously each region of organic material together with the pixels of behind which that region lies.