Display device having a plurality of pixels each comprising sub-pixels

• US 7,956,531 B2
• Filed: 01/24/2005
• Issued: 06/07/2011
• Est. Priority Date: 01/30/2004
• Status: Expired due to Fees

• Current Assignee: Cambridge Display Technology Limited (Sumitomo Chemical Company Limited)
• Original Assignee: Cambridge Display Technology Limited (Sumitomo Chemical Company Limited)
• Inventors: Smith, Euan C.
• Primary Examiner(s): MACCHIAROLO, PETER J
• Application Number:
  US10/587,602
• Publication Number:
  US 20070216610A1
• Time in Patent Office: 2,325 Days
• Field of Search: 313/503, 315/169.3, 345/76
• US Class Current: 313/505
• CPC Class Codes: G09G 2300/0452 Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/3216 using a passive matrix
• CPC Class Codes: G09G 3/3225 using an active matrix
• CPC Class Codes: H05B 45/60 Circuit arrangements for operating LEDs comprising organic material, e.g. for operating organic light-emitting diodes [OLED] or polymer light-emitting diodes [PLED]
• CPC Class Codes: H10K 59/12 Active-matrix OLED [AMOLED] displays
• CPC Class Codes: H10K 59/131 Interconnections, e.g. wiring lines or terminals
• CPC Class Codes: H10K 59/352 the areas of the RGB subpixels being different
• CPC Class Codes: H10K 59/353 characterised by the geometrical arrangement of the RGB subpixels
• CPC Class Codes: H10K 59/86 Series electrical configurations of multiple OLEDs
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

An organic light emitting diode (OLED) display device is described, the display device having a plurality of pixels each comprising at least two sub-pixels of different types, a first sub-pixel type comprising an OLED device including a first type of OLED material and a second sub-pixel type comprising an OLED device including a second type of OLED material, and wherein at least one of said first and second types of sub-pixel comprises a plurality of series-connected OLED devices. Employing series-connected sub-pixels where different types of OLED material are used for a display such as a color, active matrix OLED display facilitates balancing sub-pixel drive voltages and hence enables the production of display devices with improved efficiency.

Claims

1. An organic light emitting diode (OLED) display device, the display device having a plurality of pixels each comprising at least two sub-pixels of different types, a first sub-pixel type comprising an OLED device including a first type of OLED material and a second sub-pixel type comprising an OLED device including a second type of OLED material, wherein the OLED device including said first type of OLED material has a lower drive voltage than the OLED device including said second type of OLED material and a said pixel has a common power supply line for supplying power to said at least two sub-pixels, and wherein the first and second sub-pixel types comprise different number of series connected devices.

2. An OLED display device as claimed in claim 1 wherein each of said series connected devices of a given type has substantially the same light emissive area.

3. An OLED display device as claimed in claim 1 wherein said first and second types of OLED material have different peak emission wavelengths.

4. An OLED display device as claimed in claim 1 wherein a said pixel comprises three sub-pixels of different types, a said pixel including a third sub-pixel type comprising an OLED device including a third type of OLED material.

5. An OLED display device as claimed in claim 4 wherein at least two of said sub-pixel types comprise a plurality of series-connected OLED devices.

6. An OLED display device as claimed in claim 1 further comprising a drive transistor associated with each sub-pixel.

7. An OLED display device as claimed in claim 1 wherein said first type of OLED material comprises a fluorescent material.

8. An OLED display device as claimed in claim 7 wherein said second type of OLED material comprises a phosphorescent OLED material.

9. An OLED display device as claimed in claim 1 wherein said first type of OLED material comprises a polymer material.

10. An OLED display device as claimed in claim 9 wherein said second type of OLED material comprises a dendrimer OLED material or small molecule OLED material.

11. An active matrix color display incorporating the display device of claim 1.