Photonic MEMS and structures

• US 20030043157A1
• Filed: 08/19/2002
• Published: 03/06/2003
• Est. Priority Date: 10/05/1999
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Iridigm Display Corporation (Qualcomm, Inc.)
• Inventors: Miles, Mark W.
• Granted Patent: US 7,110,158 B2
• Time in Patent Office: Days
• US Class Current: 345/540
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G01J 3/0256 Compact construction
• CPC Class Codes: G01J 3/26 using multiple reflection, e.g. Fabry-Perot interferometer, variable interference filters
• CPC Class Codes: G01L 5/0047 measuring forces due to residual stresses
• CPC Class Codes: G02B 2006/12104 Mirror; Reflectors or the like
• CPC Class Codes: G02B 2006/12109 Filter
• CPC Class Codes: G02B 2006/12126 Light absorber
• CPC Class Codes: G02B 2006/12159 Interferometer
• CPC Class Codes: G02B 2006/12164 Multiplexing; Demultiplexing
• 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 26/02 for controlling the intensity of light G02B26/004 takes precedence
• CPC Class Codes: G02B 26/08 for controlling the direction of light in light guides G02B6/35
• 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: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 5/02 Diffusing elements; Afocal elements
• CPC Class Codes: G02B 6/12007 forming wavelength selective elements, e.g. multiplexer, demultiplexer
• CPC Class Codes: G02B 6/122 Basic optical elements, e.g. light-guiding paths
• CPC Class Codes: G02B 6/1225 comprising photonic band-gap structures or photonic lattices
• CPC Class Codes: G02B 6/13 Integrated optical circuits characterised by the manufacturing method
• CPC Class Codes: G02B 6/266 the optical element being an attenuator
• CPC Class Codes: G02B 6/3516 : the reflective optical element moving along the beam path, e.g. controllable diffractive effects using multiple micromirrors within the beam
• CPC Class Codes: G02B 6/3522 : the optical element enabling or impairing total internal reflection using evanescent coupling G02B6/3536
• CPC Class Codes: G02B 6/353 : the optical element being a shutter, baffle, beam dump or opaque element absorbers on light guide termination G02B6/243
• CPC Class Codes: G02B 6/3536 : involving evanescent coupling variation, e.g. by a moving element such as a membrane which changes the effective refractive index mode converters G02B6/14; adjustable lateral coupling between waveguides G02B6/283; electro- optical refractive index variations G02F1/0118
• CPC Class Codes: G02B 6/3546 : NxM switch, i.e. a regular array of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/3548 : 1xN switch, i.e. one input and a selectable single output of N possible outputs
• CPC Class Codes: G02B 6/356 : in an optical cross-connect device, e.g. routing and switching aspects of interconnecting different paths propagating different wavelengths to (re)configure the various input and output links switching polarized beams G02B6/3594; power equalizers G02B6/356 and G02B6/3594; path selecting means H04Q11/0001
• CPC Class Codes: G02B 6/357 : Electrostatic force electrostatic forces controlling reflecting elements in general G02B26/0841
• CPC Class Codes: G02B 6/3578 : Piezoelectric force piezoelectric forces controlling reflecting elements in general G02B26/0858; piezo-optic devices G02F1/0131
• CPC Class Codes: G02B 6/3584 : constructional details of an associated actuator having a MEMS construction, i.e. constructed using semiconductor technology such as etching MEMS per se B81B, B81C
• CPC Class Codes: G02B 6/3594 : Characterised by additional functional means, e.g. means for variably attenuating or branching or means for switching differently polarized beams
• CPC Class Codes: G02B 6/3598 : Switching means directly located between an optoelectronic element and waveguides, including direct displacement of either the element or the waveguide, e.g. optical pulse generation based on changing the optical properties of the medium G02F1/00; optical pulse generation in optical transmitters H04B10/508; optical pulse generation by controlling laser operation H01S3/00
• CPC Class Codes: G02B 6/43 : Arrangements comprising a plurality of opto-electronic elements and associated optical interconnections
• CPC Class Codes: G09G 2310/02 : Addressing, scanning or driving the display screen or processing steps related thereto
• CPC Class Codes: G09G 2310/0254 : Control of polarity reversal in general, other than for liquid crystal displays
• CPC Class Codes: G09G 2310/06 : Details of flat display driving waveforms
• CPC Class Codes: G09G 3/3466 : based on interferometric effect

Abstract

An interference modulator (Imod) incorporates anti-reflection coatings and/or micro-fabricated supplemental lighting sources. An efficient drive scheme is provided for matrix addressed arrays of IMods or other micromechanical devices. An improved color scheme provides greater flexibility. Electronic hardware can be field reconfigured to accommodate different display formats and/or application functions. An IMod'"'"'s electromechanical behavior can be decoupled from its optical behavior. An improved actuation means is provided, some one of which may be hidden from view. An IMod or IMod array is fabricated and used in conjunction with a MEMS switch or switch array. An IMod can be used for optical switching and modulation. Some IMods incorporate 2-D and 3-D photonic structures. A variety of applications for the modulation of light are discussed. A MEMS manufacturing and packaging approach is provided based on a continuous web fed process. IMods can be used as test structures for the evaluation of residual stress in deposited materials.

Claims

1. A reflective display comprising an anti-reflection coating on a viewed surface of the display, the anti-reflection coating being configured to increase the contrast ratio of the display.

2. The display of claim 1 comprising interferometric modulators.

3. An arc-lamp structure comprising a monolithic fabrication on a planar substrate, the fabrication comprising deposited thin films and/or a material of the substrate, the fabrication including thin film electrodes between which an arc is to be formed.

4. A transmissive or reflective display device incorporating the arc-lamp structure of claim 3.

5. A line-at-a-time electronic driving method comprising

applying a bias voltage to rows (or columns) of a device,

applying data voltages to the columns (or rows) alternately about a value of the bias voltage,

actuation of the device occurring when the difference between the values of the data voltage and the select voltage is above a first predetermined level,

release of the device occurring when the difference between the values of the data voltage and the select voltage is below a second predetermined level lowest, and

the device maintaining its state when the select voltage is at the bias level.

6. The method of claim 5 in which the device comprises multiple MEMS devices.

7. Apparatus comprising

a reflective display comprising pixel elements each configured to contribute a controlled amount of white and saturated color, and

a controller that controls the pixels to provide a full-color display.

8. The apparatus of claim 7 in which the display comprises interferometric modulators.

9. An electronic product comprising

a core non-general-purpose processor that is reconfigurable to perform any selected one or more of multiple software applications or functions, and

a control element that enables a user to reconfigure the processor to use any of the software applications or functions.

10. The electronic product of claim 9 further comprising peripherals, the peripherals being used or reconfigured or made accessible for interaction based on a configuration of the core processor.

11. An interferometric modulator comprising

a cavity that provides for actuation of the modulator, and

a separate cavity that provides an interference effect.

12. An interferometric modulator comprising a structure associated with actuation of the modulator, and

an interferometric cavity having walls,

the structure being obscured by at least one of the walls of the interferometric cavity.

13. An interferometric modulator comprising

a thin film stack, and

a structure associated with actuation of the modulator, the structure being deposited directly upon the thin film stack, interference of the structure and the stack causing the stack to reflect minimal amounts of light.

14. An interferometric modulator comprising

a movable wall that

is configured as a spiral by induced residual stresses, in one mode of operation, and

is un-rolled to form a plate which acts interferometrically on light in another mode of operation.

15. A monolithic MEM modulator comprising

a movable plate that is held on a supporting substrate and

is configured to selectively obstruct a path of light,

is movable rotationally, about a hinge, in a plane normal to a surface of the supporting substrate, and

is actuated by electrostatic forces applied between it and electrodes at the surface of the substrate.

16. The modulator of claim 15 wherein colors or dark states are imparted by the interferometric properties of thin film stacks deposited on the modulator structure.

17. A micromechanical switch comprising

a supporting substrate, and

a movable component that effects switching by motion in a plane parallel to a plane of the substrate.

18. The switch of claim 17 wherein the movable component provides electrical contact between a source and a drain.

19. The switch of claim 17 wherein the movable component includes an insulating element.

20. A voltage switching or logic component that includes the switch of claim 17.

21. An electronic or MEMS-based device that incorporates the voltage switching or logic component of claim 20.

22. A dynamic micromechanical structure comprising a structure having an index of refraction that varies in a periodic fashion along more than one of at least two orthogonal axis.

23. A device for processing light comprising the micromechanical structure of claim 22.

24. The device of claim 23 configured to select and/or redirect specific frequencies of light from a waveguide that is propagating multiple light frequencies.

25. The device of claim 24 wherein a movable portion of the structure is configured to introduce a defect into a periodic photonic structure.

26. The device of claim 24 wherein the movable portion of the structure is configured to move a multi-dimensional photonic structure to change overall optical properties of the device.

27. A process for fabricating multi-dimensional photonic structures in conjunction with microelectromechanical structures, the process comprising

holographic patterning or polymeric self-assembly processes or self-organizing particle suspensions.

28. A process for introducing defects into multidimensional photonic structures, the process comprising

using a beam of atomic or sub-atomic particles to modify part of the photonic structure, by the addition or removal of material, by alteration of optical properties of a material or, by using micro-electrodeposition to add material.

29. A process for introducing defects into a multidimensional photonic structure, the process forming features on surface of a substrate, the features configured to provide locations for development of defects in a later formed photonic structure.

30. A device comprising

a substrate,

an interferometric modulator fabricated on the substrate, the interferometric modulator configured to modulate light propagating within the substrate upon which it is fabricated, in a direction that is generally parallel to the surface of the substrate.

32. The modulator of claims 30 and 31 configured to function as a variable attenuator.

31. A device comprising a substrate and a metallic MEM structure formed on the substrate, the MEM structure being configured to modulate light that is propagating as guided waves.

33. A dynamic micromechanical structure comprising a substrate, and a reflecting optic on the substrate, the reflecting optic when actuated, re-directing light which is incident upon it and is propagating within the substrate, towards another optical structure.

37. The device of claim 33 configured to couple light into or out of the substrate.

39. An optical device of claim 37 further comprising anti-reflection coatings configured to couple and decouple light into and out of the substrate/waveguide.

42. The device of claim 37 wherein the micromechanical structures comprise a tunable filter.

43. An N×

N optical switch comprising the devices of claims 33, 34, or 37.

44. A wavelength selective switch comprising the devices of claims 33, 34, or 37.

45. An optical mixer comprising the devices of claims 33, 34, and 37.

48. The method of claim 44 further comprising automatically determining the stress of the deposited materials based upon the patterns of reflected light.

49. The method of claim 45 further comprising determining the residual stress of films during and after deposition.

34. A static microfabricated structure comprising a substrate and a mirror fabricated on or in close proximity to the substrate, the mirror being configured to redirect light that is incident upon it and is propagating within the substrate.

36. The device of claim 34 wherein the reflecting optic comprises a mirror.

35. An optical switch comprising

a dynamic micromechanical structure comprising a reflecting optic and a fixed microstructure incorporating a reflecting optic,

the two structures being fabricated on opposite sides of a substrate/waveguide,

the reflecting optics being oriented such that when a beam of light propagating within the substrate/waveguide is incident upon the dynamic structure in an actuated state, the optical path of the combined reflecting optics allows the path of the light'"'"'s propagation within the substrate/waveguide to be altered arbitrarily.

38. An optical device comprising

micromechanical structures configured to process light is propagating within a substrate/waveguide, and an optical or electronic device configured to thereafter intercept or manipulate the light.

40. The optical device of claim 38 further comprising an optical superstructure that is capable of supporting a combination of static microfabricated components, dynamic micromechanical components, and electronic components, and that is attached to the substrate/waveguide.

41. An optical path repositioning device comprising a patterned block of dielectric material deposited upon the surface of a substrate/waveguide.

46. A process for fabricating micromechanical structures comprising

feeding a continuous web of a plastic supporting substrate through a series of tools for depositing, patterning, and etching deposited films.

47. A method of measuring a residual stress of deposited materials that comprise an interferometric cavity which is deformed by the deposition of the materials to be measured, the method comprising determining the deformation of the microstructure by measuring a pattern of wavelengths of light reflected by the cavity.

50. A dynamic micromechanical structure comprising a a dielectric, metallic, or semiconducting film which is discontinuous, the optical properties of said film differing from those of a continuous film because of the discontinuity.

51. A dynamic micromechanical structure comprising a a dielectric, metallic, or semiconducting film which has been etched in such a way as to produce a continuous variation in the optical properties of the film through its depth.