OLED display with composite photosensor

• US 7,288,753 B2
• Filed: 05/05/2004
• Issued: 10/30/2007
• Est. Priority Date: 05/05/2004
• Status: Active Grant

• Current Assignee: Global OLED Technology LLC (LG Display Co., Ltd.)
• Original Assignee: Eastman Kodak Company
• Inventors: Cok, Ronald S.
• Primary Examiner(s): Luu; Thanh X.
• Application Number:
  US10/839,616
• Publication Number:
  US 20050248264A1
• Time in Patent Office: 1,273 Days
• Field of Search: 250/208.1, 250/214.R, 345 80- 84, 345/207, 257 80- 84
• US Class Current: 250/214.00R
• CPC Class Codes: H10K 59/13 comprising photosensors that control luminance

Abstract

An OLED display and photo-sensor is described, comprising: a substrate; a composite light sensor made up of a plurality of individual thin-film light sensitive elements located over the substrate and connected in parallel to provide a common signal; a first transparent electrode located over the composite light sensor; one or more organic layers comprising an OLED located on the transparent electrode and emitting light through the transparent electrode and to the composite light sensor; and a second electrode located on the one or more organic layers comprising an OLED. The OLED display device provides a means to measure the light output of the OLED display device while maximizing the light output and is useful in measuring incident ambient illumination.

Claims

1. An OLED display and photo-sensor, comprising:

a) a substrate;

b) a composite light sensor made up of a plurality of individual thin-film light sensitive elements located over the substrate and connected in parallel with electrical connections to provide a common signal;

C) a first transparent electrode located over the composite light sensor;

d) one or more organic layers comprising an OLED located on the transparent electrode and emitting light through the transparent electrode and to the composite light sensor; and

e) a second transparent electrode located on the one or more organic layers comprising an OLED, wherein the OLED display is a top-emitter OLED display.

2. The OLED display and photo-sensor claimed in claim 1, wherein the individual thin-film light sensitive elements comprise photo-transistors.

3. The OLED display and photo-sensor claimed in claim 1, wherein composite light sensor comprises thin film light sensitive elements having two or more relatively elongated terminals that are approximately parallel in the direction of elongation, where the lengths of the elongated terminals are greater than a distance between the elongated terminals.

4. The OLED display and photo-sensor claimed in claim 1, further comprising a planarizing layer between the composite light sensor and the first transparent electrode.

5. The OLED display and photo-sensor claimed in claim 1, further comprising a reflective layer located over the substrate, wherein the composite light sensor is located between the reflective layer and the first transparent electrode.

6. The OLED display and photo-sensor claimed in claim 1, wherein each of the thin film light sensitive elements includes a terminal located on the bottom side of the light sensitive element.

7. The OLED display and photo-sensor claimed in claim 1, wherein each of the light sensitive elements includes at least two terminals, and adjacent light sensitive elements in a composite light sensor share a terminal.

8. The OLED display and photo-sensor claimed in claim 1, further comprising circuitry for measuring the ambient illumination incident on the composite light sensor and the light output by the OLED.

9. The OLED display and photo-sensor claimed in claim 1, wherein the OLED display is an active-matrix display and further including thin-him electronic components for operating the OLEDs in the display.

10. The OLED display and photo-sensor claimed in claim 9, wherein the plurality of thin-film light sensitive elements are formed in common manufacturing steps with the thin-film electronic components.

11. An OLED display and photo-sensor, comprising:

a) a substrate;

b) a composite light sensor made up of a plurality of individual thin-film light sensitive elements located over the substrate and connected in parallel with electrical connections to provide a common signal;

C) a first transparent electrode located over the composite light sensor;

d) one or more organic layers comprising an OLED located on the transparent electrode and emitting light through the transparent electrode and to the composite light sensor; and

e) a second electrode located on the one or more organic layers comprising an OLED;

f) a reflective layer located over the second electrode, wherein the OLED display is a bottom-emitter OLED display.

12. The OLED display and photo-sensor claimed in claim 11, wherein the individual thin-film light sensitive elements comprise photo-transistors.

13. The OLED display and photo-sensor claimed in claim 11, wherein composite light sensor comprises thin film light sensitive elements having two or more relatively elongated terminals that are approximately parallel in the direction of elongation, where the lengths of the elongated terminals are greater than a distance between the elongated terminals.

14. The OLED display and photo-sensor claimed in claim 11, further comprising a planarizing layer between the composite light sensor and the first transparent electrode.

15. The OLED display and photo-sensor claimed in claim 11, wherein each of the thin film light sensitive elements includes a terminal located on the bottom side of the light sensitive element.

16. The OLED display and photo-sensor claimed in claim 11, wherein each of the thin film light sensitive elements includes a terminal located on the top side of the light sensitive element.

17. The OLED display and photo-sensor claimed in claim 11, wherein each of the thin film light sensitive elements includes a terminal and the terminal is located on the bottom side of some of the light sensitive elements, and the terminal is located on the top side of some of the light sensitive elements.

18. The OLED display and photo-sensor claimed in claim 17, wherein the light sensitive elements including a terminal located on the bottom side alternate with the light sensitive elements including a terminal located on the top side.

19. The OLED display and photo-sensor claimed in claim 11, wherein each of the light sensitive elements includes at least two terminals, and adjacent light sensitive elements in a composite light sensor share a terminal.

20. The OLED display and photo-sensor claimed in claim 11, further comprising circuitry for measuring the ambient illumination incident on the composite light sensor and the light output by the OLED.

21. The OLED display and photo-sensor claimed in claim 11, wherein the OLED display is an active-matrix display and further including thin-film electronic components for operating the OLEDs in the display.

22. The OLED display and photo-sensor claimed in claim 21, wherein the plurality of thin-film light sensitive elements are formed in common manufacturing steps with the thin-film electronic components.

23. A method of calibrating the composite light sensor of an OLED display and photo-sensor, comprising the steps of:

a) providing the OLED display and photo-sensor, including;

i) a substrate;

ii) a composite light sensor made up of a plurality of individual thin-film light sensitive elements located over the substrate and connected in parallel with electrical connections to provide a common signal;

iii) a first transparent electrode located over the composite light sensor;

iv) one or more organic layers comprising an OLED located on the transparent electrode and emitting light through the transparent electrode and to the composite light sensor;

v) a second electrode located on the one or more organic layers;

b) turning off the OLED;

c) exposing the composite light sensor to a known incident illumination;

d) sensing and measuring the ambient light incident on the composite light sensor; and

e) storing the measured response of the composite light sensor comprising an OLED.

24. A method according to claim 23, further comprising the steps of:

f) tuning on the OLED;

g) sensing and measuring the OLED light incident on the composite light sensor; and

h) correcting the OLED light output by the OLED display.

25. A method according to claim 24, further comprising the steps of:

i) sensing and measuring the combined GLEE) and ambient light incident on the composite light sensor; and

j) subtracting the measured ambient light from the combined light to obtain the light output by the OLED.