Analog IMOD having a color notch filter

• US 8,970,941 B2
• Filed: 06/23/2014
• Issued: 03/03/2015
• Est. Priority Date: 01/26/2012
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Ma, Jian, Chang, Tallis Young, Hong, John Hyunchul, Bita, Ion
• Primary Examiner(s): PINKNEY, DAWAYNE
• Application Number:
  US14/312,527
• Publication Number:
  US 20140300946A1
• Time in Patent Office: 253 Days
• Field of Search: 359290-292, 359223-225, 359/245, 359260-263, 359/198, 359/298, 359301-303, 359317-318, 359/237, 359/242
• US Class Current: 359/290
• 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: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: H05K 3/10 in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base

Abstract

This disclosure provides systems, methods and apparatus related to an electromechanical display device. In one aspect, an analog interferometric modulator (AIMOD) includes a reflective display pixel having a movable reflective layer and a stationary absorber layer, the reflective layer and absorber layer defining a cavity therebetween. A color notch filter may be employed to produce an improved white state. In some implementations, the color notch filter is positioned on a side of the substrate opposite the absorber layer. In some other implementations, the color notch filter is positioned between the substrate and the movable reflective layer.

Claims

1. A device, comprising:

an analog interferometric modulator (AIMOD) including

a substrate having a forward side that is exposed to receive incident light and a rearward side opposite the first side;

a first electrode disposed rearward of the substrate;

an absorber disposed rearward of the substrate;

a second electrode rearward of the first electrode and the absorber such that there is a cavity between the second electrode and the first electrode;

a reflective movable layer coupled to the second electrode, the movable layer configured to move to at least three different positions relative to the absorber in response to a voltage applied across the first electrode and the second electrode; and

a notch filter disposed forward of the movable layer and configured to at least partially absorb light having a wavelength between about 400 nm and about 600 nm.

2. The device of claim 1, wherein the movable layer includes a metal reflector and one or more dielectric layers disposed on the surface of the metal reflector nearest the absorber.

3. The device of claim 1, wherein the notch filter is disposed between the first electrode and the substrate.

4. The device of claim 1, wherein the notch filter is disposed between the first electrode and the cavity.

5. The device of claim 1, further comprising a cover glass disposed such that the substrate is between the cover glass and the movable layer, wherein the cover glass includes the notch filter.

6. The device of claim 1, wherein the notch filter includes at least one of:

a thin film dye, a plurality of metal nanoparticles, a Rugate filter and a holographic filter.

7. The device of claim 1, wherein the movable layer is configured to be positionable at a first distance from the absorber such that light reflected by the movable layer and the optical appears substantially white, and wherein the notch filter is positioned to receive incident light and receive the light reflected from the movable layer, and to at least partially absorb light having a wavelength between about 400 nm and about 600 nm.

8. The device of claim 1, wherein the notch filter is configured to decrease a difference in chromaticity between the reflective color of the AIMOD and that of illuminant D65, when the movable layer is positioned at a first distance from the optical stack that produces a reflection of light having a substantially white appearance.

9. The device of claim 8, wherein the first distance is between about 0 nm and about 20 nm.

10. The device of claim 1, wherein the absorber includes the first electrode.

11. The device of claim 1, wherein the reflective movable layer includes the second electrode.

12. The device of claim 1, further comprising:

a display that includes the AIMOD;

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

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

13. The device of claim 12, further comprising:

a driver circuit configured to send at least one signal to the display; and

a controller configured to send at least a portion of the image data to the driver circuit.

14. The device of claim 13, further comprising:

an image source module configured to send the image data to the processor, wherein the image source module includes at least one of a receiver, transceiver and transmitter.

15. The device of claim 13, further comprising:

an input device configured to receive input data and to communicate the input data to the processor.

16. A device, comprising:

a means for modulating light including

a substrate having a forward side that is exposed to receive incident light and a rearward side opposite the first side;

a first means for conducting electrostatic charge, the first conducting means disposed rearward of the substrate;

a first means for absorbing light disposed rearward of the substrate;

a second means for conducting electrostatic charge, the second conducting means being positioned rearward of the first conducting means and the first absorbing means, such that there is a cavity between the second conducting means and the first conducting means;

a means for reflecting light, the reflecting means coupled to the second conducting means, the reflecting means configured to move to at least three different positions relative to the first absorbing means in response to a voltage applied across the first conducting means and the second conducting means; and

a second means for absorbing light disposed forward of the reflecting means and configured to at least partially absorb light having a wavelength between about 400 nm and about 600 nm.

17. The device of claim 16, wherein the first conducting means includes a stationary first electrode, wherein the second conducting means includes a movable second electrode, wherein the first absorbing means includes an optical stack having an absorbing layer, wherein the reflecting means includes a reflective movable layer, and wherein the second absorbing means includes a notch filter.

18. The device of claim 16, wherein the second absorbing means includes at least one of a thin film dye, a plurality of metal nanoparticles, a Rugate filter and a holographic filter.

19. A method of manufacturing a device, comprising:

providing a substrate having a forward side that is exposed to receive incident light and a rearward side opposite the first side;

disposing a stationary first electrode rearward of the substrate;

disposing an absorber rearward of the substrate;

disposing a reflective movable layer and a second electrode rearward of the first electrode and the absorber;

forming a cavity between the second electrode and the first electrode, wherein the movable layer is configured to move in the cavity to at least three different positions relative to the optical stack in response to a voltage applied across the first electrode and the second electrode; and

disposing a notch filter forward of the movable layer as the substrate, wherein the notch filter is configured to at least partially absorb light having a wavelength between about 400 nm and about 600 nm.

20. The method of claim 19, wherein disposing the notch filter includes arranging the notch filter between the first electrode and the substrate.

21. The method of claim 19, further comprising disposing a cover glass over the first side of the substrate, and wherein disposing the notch filter includes arranging the notch filter on the cover glass.

22. The method of claim 19, wherein the notch filter includes at least one of:

a thin film dye, a plurality of metal nanoparticles, a Rugate filter and a holographic filter.

23. The method of claim 19, wherein the movable layer is configured to be positionable at a first distance from the absorber such that light reflected by the movable layer appears substantially white, and wherein the notch filter is positioned to receive light reflected from the movable layer and to absorb light having a wavelength between about 400 nm and about 600 nm.

24. The method of claim 23, wherein the first distance is between about 0 nm and about 20 nm.

25. The method of claim 19, wherein the notch filter is configured to decrease a difference in chromaticity between the reflective color of the device and that of illuminant D65, when the movable layer is positioned at a first distance from the absorber that produces a reflection of light having a substantially white appearance.