Photonic MEMS and structures

• US 7,236,284 B2
• Filed: 10/21/2005
• Issued: 06/26/2007
• Est. Priority Date: 05/01/1995
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: IDC, LLC
• Inventors: Miles, Mark W.
• Primary Examiner(s): Spector; David N.
• Assistant Examiner(s): TRA, TUYEN Q
• Application Number:
  US11/255,347
• Publication Number:
  US 20060033975A1
• Time in Patent Office: 613 Days
• Field of Search: 359/290, 359/291, 359/293, 359/295, 359/298, 359/223, 359/224, 359/320, 359/322, 359/324, 359/237
• US Class Current: 359/237
• 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. An optical modulator comprising:

a substrate;

a first optical layer which is at least partially transmissive to incident light, the first optical layer spaced from the substrate; and

a second optical layer which is at least partially reflective to incident light, the second optical layer between the substrate and the first optical layer and linearly displaceable between a first position and a second position, wherein movement of the second optical layer between the first position and the second position modulates a reflectivity of the optical modulator.

2. The optical modulator of claim 1, further comprising an electrode layer on the substrate.

3. The optical modulator of claim 2, further comprising an insulating layer on the electrode layer.

4. The optical modulator of claim 1, wherein the first optical layer comprises chromium.

5. The optical modulator of claim 1, wherein the first optical layer is supported by a transparent superstructure.

6. The optical modulator of claim 5, wherein the transparent superstructure comprises an organic material.

7. The optical modulator of claim 5, wherein the transparent superstructure comprises an inorganic material.

8. The optical modulator of claim 1, wherein the second optical layer comprises aluminum.

9. The optical modulator of claim 1, wherein the second optical layer is opaque.

10. The optical modulator of claim 1, wherein light modulated by the optical modulator is not transmitted through the substrate.

11. The optical modulator of claim 1, wherein the first position corresponds to a black state of the optical modulator and the second position corresponds to a white state of the optical modulator, the optical modulator having a higher reflectivity when in the white state than when in the black state.

12. The optical modulator of claim 1, wherein the first position corresponds to a first color state of the optical modulator and the second position corresponds to a second color state of the optical modulator, the reflectivity of the optical modulator being peaked at a first wavelength when in the first color state and the reflectivity of the optical modulator being peaked at a second wavelength when in the second color state, the first wavelength different than the second wavelength.

13. An optical modulator comprising:

means for supporting the optical modulator;

means for at least partially transmitting an incident light, the transmitting means spaced from the supporting means; and

means for at least partially reflecting incident light, the reflecting means between the supporting means and the transmitting means, the reflecting means linearly displaceable between a first position and a second position, wherein movement of the reflecting means between the first position and the second position modulates a reflectivity of the optical modulator.

14. The optical modulator of claim 13, wherein the supporting means comprises a substrate.

15. The optical modulator of claim 14, wherein the transmitting means comprises a first optical layer which is at least partially transmissive to incident light, the first optical layer spaced from the substrate.

16. The optical modulator of claim 14, wherein the reflecting means comprises a second optical layer which is at least partially reflective to light, the second optical layer between the substrate and the first optical layer and movable between the first position and the second position.

17. A method of modulating light, the method comprising:

providing an optical modulator comprising a substrate, a first optical layer which is at least partially transmissive to incident light, and a second optical layer which is at least partially reflective to incident light, the first optical layer spaced from the substrate, the second optical layer between the substrate and the first optical layer and linearly displaceable between a first position and a second position;

irradiating the first optical layer with light;

irradiating the second optical layer with a portion of the light transmitted through the first optical layer; and

moving the second optical layer between the first position and the second position.

18. A method of forming an optical modulator, the method comprising:

providing a substrate;

forming a first optical layer spaced from the substrate, the first optical layer at least partially transmissive to incident light; and

forming a second optical layer between the substrate and the first optical layer, the second optical layer at least partially reflective to incident light, the second optical layer linearly displaceable between a first position and a second position.

19. A device comprising a plurality of optical modulators on a substrate, wherein each optical modulator comprises:

a first optical layer which is at least partially transmissive to incident light, the first optical layer spaced from the substrate; and

a second optical layer which is at least partially reflective to incident light, the second optical layer between the substrate and the first optical layer and linearly displaceable between a first position and a second position, wherein movement of the second optical layer between the first position and the second position modulates a reflectivity of the optical modulator.

20. The device of claim 19, wherein the device comprises a flat-panel display.

21. The device of claim 19, wherein the device comprises a fiber-optic modulator, switch, or attenuator.

22. The device of claim 19, wherein the device comprises a projection display.

23. An optical modulator comprising:

a substrate;

a first optical layer which is at least partially transmissive to incident light, the first optical layer spaced apart from the substrate and comprising chromium and having a thickness of approximately 40 angstroms; and

a second optical layer which is at least partially reflective to incident light, the second optical layer between the substrate and the first optical layer and movable between a first position and a second position, wherein movement of the second optical layer between the first position and the second position modulates a reflectivity of the optical modulator.

24. An optical modulator comprising:

a substrate;

a first optical layer which is at least partially transmissive to incident light, the first optical layer spaced from the substrate and supported by a transparent superstructure comprising SU-8 polyimide; and

a second optical layer which is at least partially reflective to incident light, the second optical layer between the substrate and the first optical layer and movable between a first position and a second position, wherein movement of the second optical layer between the first position and the second position modulates a reflectivity of the optical modulator.

25. An optical modulator comprising:

a substrate;

a first optical layer which is at least partially transmissive to incident light, the first optical layer spaced from the substrate; and

a second optical layer which is at least partially reflective to incident light, the second optical layer comprising aluminum and having a thickness of approximately 500 angstroms, the second optical layer between the substrate and the first optical layer and movable between a first position and a second position, wherein movement of the second optical layer between the first position and the second position modulates a reflectivity of the optical modulator.