Photonic MEMS and structures

• US 7,110,158 B2
• Filed: 08/19/2002
• Issued: 09/19/2006
• Est. Priority Date: 10/05/1999
• Status: Expired due to Term

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: IDC, LLC
• Inventors: Miles, Mark W.
• Primary Examiner(s): Dang, Hung Xuan
• Application Number:
  US10/224,029
• Publication Number:
  US 20030043157A1
• Time in Patent Office: 1,492 Days
• Field of Search: 359/291, 359/578, 359/528, 359/529, 359/290, 359/522, 359/237, 359/242
• US Class Current: 359/291
• 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 method of controlling a MEMS device configurable to first and second states, the method comprising:

actuating the MENS device to a first state with a first electrical signal, such that a charge is built up on the device ; and

actuating the MEMS device to said first state with a second electrical signal, such that at least a portion of the built up charge is removed from the device.

2. The method of claim 1 in which the MEMS device comprises an interference modulator.

3. The method of claim 1 in which the first and second electrical signals comprise a voltage having a controlled waveform.

4. The method of claim 3 in which the voltage comprises a DC voltage.

5. The method of claim 4 in which the DC voltage has a polarity opposite to a polarity of a voltage used to drive the device.

6. A method of claim 1, wherein the first electrical signal comprises a first frame of display data and the second electrical signal comprises a second frame of display data.

7. A method of controlling a MEMS device which operates at least in part according to an alterable electroptical hysteresis curve, the method comprising:

driving the MEMS device with an electrical signal, wherein the MEMS device operates according to the hysteresis curve in response to the electrical signal; and

altering the hysteresis curve with the electrical signal.

8. The method of claim 7 in which the electrical signal comprises at least one of a voltage waveform, voltage polarities, waveform timing, or charge buildup.

9. The method of claim 7 in which the device is part of an array of devices and the electrical signal is applied in line-at-a time fashion.

10. The method of claim 7 in which the electrical signal is applied in conjunction with an applied DC bias voltage.

11. The method of claim 7 in which the electrical energy offsets charge buildup on the device.

12. A control device configured to control a MEMS device configurable to first and second states, the device comprising:

a first circuit configrued to actuate the MEMS device to a first state with a first electrical signal, such that a charge is built up on the device; and

a second circuit configured to actuate the MIMS device to said first state with a second electrical signal, such that at least a portion of the built up charge is removed from the device.

13. The device of claim 12, wherein the MEMS device comprises an interferometric modulator.

14. A MEMS display device which operates at least in part according to an alterable response versus applied voltage electroptical hystersis curve, wherein the hystersis curve is altered by the applied voltage.

15. The device of claim 14, wherein the MEMS device comprises an interferometric modulator.

16. A method of actuating a MEMS display element to display a portion of an image corresponding to image data, the element being configurable to first and second states, and comprising a portion of an array of MEMS display elements, said method comprising:

actuating said MEMS display element to said first state by application of voltage producing a potential difference on the display element of a first polarity in response to the image data during a first portion of a display write process;

actuating said MEMS display element to said first state by application of voltage producing a potential difference on the display element having a polarity opposite said first polarity in response to the image data during a second portion of said display write process.

17. The method of claim 16, wherein said first portion of said display write process comprises writing a first frame of display data to said array of MEMS display elements and wherein said second portion of said display write process comprises writing a second frame of display data to said array of MEMS display elements.

18. The method of claim 17, wherein one or more other frames of display data are written to said array between said first frame and said second frame.

19. The method of claim 16, comprising actuating said MEMS display element with a potential difference of said first polarity during a third portion of said display wirte process.

22. The method of claim 16, wherein the MEMS display element comprises an interferometric modulator.

20. The method of clam 16, comprising alternately applying potential differences of opposite polarity to display elements of said array in response to the image data during alternating portions of said display write process.

21. The method of claim 20, wherein said alternating portions of said display write process comprise writing alternating frames of display data to said array of MEMS display elements.

23. A method of operating a MEMS element in an array of MEMS elements forming a display, said method comprising:

applying a first potential difference to said MEMS element, said first potential difference having a magnitude sufficient to actuate said MEMS element, and having a first polarity; and

applying a second potential difference to said MEMS element, said second potential difference being of approximately equal magnitude to said first potential difference and having a second polarity that is opposite the first polarity;

wherein said first potenital difference and said second potential difference are respectively applied to said MEMS element at times and for durations that depend on a rate at which image data is written to MEMS elements of said array, and wherein said first and second potential differences are each applied to said MEMS element in approximately equal time periods over a period of display use.

24. A system for writing image data to an array of MEMS display elements, each element being actuatable to first and second states, said system comprising:

a column driver; and

a row driver;

wherein said row driver and said column driver are configured to actuate elements of said array to a first state with a potential difference of a first polarity in response to the image data during a first portion of a display wirte process, and to actuate elements of said array to said first state with a potential difference of a second polarity, opposite the first polarity in response to the image data during a second portion of a display write process.