Devices and methods for enhancing color shift of interferometric modulators

• US 8,081,373 B2
• Filed: 10/12/2010
• Issued: 12/20/2011
• Est. Priority Date: 07/31/2007
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Kothari, Manish, Sethi, Gaurav, Griffiths, Jonathan Charles, Worthington, Eric
• Primary Examiner(s): Spector, David N
• Application Number:
  US12/902,586
• Publication Number:
  US 20110026095A1
• Time in Patent Office: 434 Days
• Field of Search: 359/290, 359/291, 359/578, 359/580, 359/584, 359/588, 359/589
• US Class Current: 359/291
• 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 3/0043 Inhomogeneous or irregular arrays, e.g. varying shape, size, height
• CPC Class Codes: G02B 3/0056 arranged along two different directions in a plane, e.g. honeycomb arrangement of lenses G02B3/0043 takes precedence; miniaturised objectives for electronic devices employing wafer level optics G02B13/0085
• CPC Class Codes: G02B 5/045 Prism arrays

Abstract

The color reflected by an interferometric modulator may vary as a function of the angle of view. A range of colors are thus viewable by rotating the interferometric modulator relative to an observer. By placing a textured layer between an observer and an interferometric modulator, a pattern which includes the range of colors may be viewed by the observer, and the range of colors may thus be viewable from a single viewing angle.

Claims

1. An assembly, comprising:

an interferometric modulator stack, including;

an absorber layer which is at least partially transmissive to incident light;

a reflective layer fixed relative to the absorber layer; and

a spacer layer disposed between the absorber layer and the reflective layer and defining an interferometric gap within the interferometric modulator stack; and

a textured layer disposed on a side of the absorber layer opposite the reflective layer, wherein the textured layer includes at least one optical feature having a curved surface, and wherein the textured layer refracts light in a substantially random pattern.

2. The assembly of claim 1, wherein the spacer layer has a substantially constant thickness.

3. The assembly of claim 1, wherein at least one of the layers within the assembly is colored.

4. The assembly of claim 1, additionally comprising a light guiding layer disposed between the textured layer and the absorber layer, wherein the light guiding layer is configured to reflect light towards the absorber layer.

5. The assembly of claim 1, wherein the interferometric modulator stack is configured to reflect at least a second-order color within the visible range when viewed at an angle normal to the interferometric modulator stack.

6. The assembly of claim 1, wherein the textured layer is configured such that the assembly reflects a pattern of multiple colors.

7. The assembly of claim 6, wherein the color pattern reflected by the assembly is distinguishable by an observer.

8. The assembly of claim 6, wherein the color pattern varies as a function of the angle of view.

9. The assembly of claim 1, additionally comprising a substrate disposed between the textured layer and the absorber layer, wherein the substrate is bonded to the textured layer via an adhesive.

10. The assembly of claim 9, wherein the adhesive includes a material having substantially the same index of refraction as an adjacent layer.

11. The assembly of claim 9, wherein the adhesive includes an optical structure disposed within the adhesive.

12. The assembly of claim 1, wherein the reflective layer is at least partially transmissive to incident light.

13. The assembly of claim 12, wherein the absorber and the reflector include substantially the same material and thickness.

14. The assembly of claim 12, additionally comprising a second textured layer disposed on the side of the interferometric modulator stack adjacent the reflective layer.

15. The assembly of claim 12, additionally comprising a light guiding layer disposed on the side of the interferometric modulator stack adjacent the reflective layer, wherein the light guiding layer is configured to reflect light towards the interferometric modulator stack.

16. The assembly of claim 1, wherein the at least one optical feature is configured to alter an effective angle of view of at least a portion of interferometric modulator stack.

17. The assembly of claim 16, wherein the optical feature includes a prismatic structure.

18. The assembly of claim 16, wherein the optical feature includes a spherical lens.

19. The assembly of claim 16, wherein the textured layer includes a first surface located adjacent the interferometric stack and a second surface located on the opposite side of the textured layer from the interferometric stack, wherein the first surface of the substrate includes said optical feature.

20. The assembly of claim 16, wherein the textured layer includes a first surface located adjacent the interferometric stack and a second surface located on the opposite side of the textured layer from the interferometric stack, wherein the second surface of the substrate includes said optical feature.

21. The assembly of claim 16, wherein the textured layer includes planar outer surfaces, and wherein said optical feature is disposed within the textured layer.