APPARATUS AND METHOD OF DUAL-MODE DISPLAY

• US 20090244683A1
• Filed: 03/28/2008
• Published: 10/01/2009
• Est. Priority Date: 03/28/2008
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Lan, Je-Hsiung
• Granted Patent: US 7,660,028 B2
• Time in Patent Office: Days
• US Class Current: 359/263
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26
• CPC Class Codes: G09G 2300/046 with an emissive area and a light-modulating area combined in one pixel
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/0866 by means of changes in the pixel supply voltage
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3466 based on interferometric effect

Abstract

One embodiment includes display comprising a light modulator configured to display a portion of an image such as a reflective light modulator, a light emitter configured to display the portion of the image and a circuit configured to selectively provide signals to at least one of the light modulator and the light emitter indicative of the portion of the image. In one such embodiment, an active matrix provides a simple, efficient drive for such devices. Other embodiments methods of making and driving such devices.

Claims

1. A display, comprising:

a reflective display element configured to display a portion of an image;

an emissive display element configured to display the portion of the image; and

a circuit configured to selectively provide signals indicative of the portion of the image to at least one of the reflective display element and the emissive display element.

2. The display of claim 1, wherein the reflective display element is configured to substantially absorb incident light when a current provided by the circuit is below a specified level and configured to reflect light when the current exceeds the specified level.

3. The display of claim 1, wherein the reflective display element comprises an reflective interferometric light modulator and the emissive display element comprises a light emitting diode.

4. The display of claim 1, wherein the portion of the image comprises a pixel.

5. A display, comprising:

at least one reflective display element configured to display a pixel of an image;

at least one emissive display element configured to display the pixel, wherein each of the reflective display element and the emissive display element are configured to display the pixel based on ambient lighting conditions.

6. The display of claim 5, wherein the reflective display element is configured to substantially absorb incident light when the emissive display element is configured to emit light with an output level below a specified output level and configured to reflect light when the output level of the emissive display element exceeds the specified output level.

7. The display of claim 5, wherein the reflective display element comprises an reflective interferometric light modulator and the emissive display element comprises a light emitting diode.

8. The display of claim 5, further comprising a circuit configured to selectively provide signals indicative of the pixel to at least one of the reflective display element and the emissive display element based on ambient lighting conditions.

9. The display of claim 8, wherein the reflective display element is configured to substantially absorb incident light when a current provided by the circuit is below a specified level and configured to reflect light when the current exceeds the specified level.

10. The device of claim 8, wherein the first display element comprises a first electrode and a second electrode, wherein the reflective display element is configured to reflect light based on the voltage difference provided by the circuit and applied between the first and second electrode.

11. The device of claim 8, wherein the circuit comprises an active matrix element.

12. A device for outputting light, the device comprising:

a first display element configured to output light based on a voltage difference applied to the first display element;

a second display element configured to output light based on a current applied to the second display element; and

a circuit configured to supply the current to the second display element and to supply the voltage difference to the first display element based on a first voltage level indicative of a portion of an image, wherein the circuit is further configured to selectively supply the current based on a second voltage level.

13. The device of claim 12, wherein the first display element comprises an interferometric modulator configured to reflectively output light.

14. The device of claim 13, wherein the first display element is configured to substantially absorb incident light when the current is below a specified level and configured to reflect light when the current exceeds the specified level.

15. The device of claim 12, wherein the second display element comprises a light emitting diode.

16. The device of claim 15, wherein the light emitting diode comprises an organic light emitting diode.

17. The device of claim 12, wherein the circuit comprises an active matrix element.

18. The device of claim 12, wherein the first display element comprises a first electrode and a second electrode, wherein the output light is based on the voltage difference applied between the first and second electrode.

19. The device of claim 18, wherein the circuit comprises:

a capacitor connected in parallel to the first display element.

20. The device of claim 19, wherein the circuit further comprises:

a transistor having a gate connected to a first electrode of the capacitor, wherein the transistor is configured to provide the current to the second display element from an source of the transistor.

21. The device of claim 20, wherein the gate of the transistor is further connected to a first electrode of the first display element, wherein the first electrode of the capacitor, the first electrode of the first display element, and the gate of the transistor are configured to receive the first voltage level indicative of the portion of the image, and wherein a second electrode of the first display element, a second electrode of the capacitor, and a drain of the transistor are configured to receive the second voltage level.

22. The device of claim 12, further comprising:

a processor that is configured to communicate with the first and second display elements, the processor being configured to process image data; and

a memory device that is configured to communicate with the processor.

23. The apparatus of claim 22, further comprising a driver circuit configured to send at least one signal to the circuit.

24. The apparatus of claim 23, further comprising a controller configured to send at least a portion of the image data to the driver circuit.

25. The apparatus of claim 22, further comprising an image source module configured to send the image data to the processor.

26. The apparatus of claim 25, wherein the image source module comprises at least one of a receiver, transceiver, and transmitter.

27. The apparatus of claim 22, further comprising an input device configured to receive input data and to communicate the input data to the processor.

28. A device for outputting light, the device comprising:

means for outputting light based on a voltage difference applied to the first display element;

means for outputting light based on a current applied to the second display element;

means for supplying the current to the second display element and for supplying the voltage difference to the first display element based on a first voltage level indicative of a portion of an image, wherein the supplying means is configured to selectively supply the current based on a second voltage level.

29. The device of claim 28, wherein the means for outputting light based on a voltage difference comprises an interferometric modulator configured to reflectively output light.

30. The device of claim 29, wherein the interferometric modulator is configured to substantially absorb incident light when the current is below a specified level and configured to reflect light when the current exceeds the specified level.

31. The device of claim 28, wherein the means for outputting light based on a current comprises a light emitting diode.

32. The device of claim 31, wherein the light emitting diode comprises an organic light emitting diode.

33. The device of claim 28, wherein the supplying means comprises an active matrix element.

34. The device of claim 28, wherein the means for outputting light based on a voltage difference comprises a first electrode and a second electrode, wherein the output light is based on the voltage difference applied between the first and second electrode.

35. The device of claim 34, wherein the supplying means comprises:

a capacitor connected in parallel to the first display element.

36. The device of claim 35, wherein the supplying means further comprises:

a transistor having a gate connected to a first electrode of the capacitor, wherein the transistor is configured to provide the current from an source of the transistor.

37. The device of claim 36, wherein the gate of the transistor is further connected to the first electrode of the means for outputting light based on the voltage difference, wherein the first electrode of the capacitor, the first electrode of the means for outputting light based on the voltage difference, and the gate of the transistor are configured to receive the first voltage level indicative of a portion of the image, and wherein the second electrode of the means for outputting light based on the voltage difference, a second electrode of the capacitor, and an source of the transistor are configured to receive the second voltage level.

38. A method of operating a display, the method comprising:

applying a voltage difference across a first display element based on a first voltage level indicative of a portion of an image; and

selectively applying a current across a second display element based at least partly on the first voltage level and based at least partly on a second voltage level,

wherein the voltage difference is applied so that the first display element substantially absorbs incident light when the current is below a specified level and reflects light when the current exceeds the specified level.

39. The method of claim 38, further comprising:

receiving data indicative of ambient lighting; and

determining the first voltage level and the second voltage level at least partly on the data.