SYSTEMS AND METHODS OF CONTROLLING MICRO-ELECTROMECHANICAL DEVICES

• US 20070146376A1
• Filed: 11/29/2006
• Published: 06/28/2007
• Est. Priority Date: 10/05/1999
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: IDC, LLC
• Inventors: Miles, Mark
• Granted Patent: US 7,355,782 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 control circuit for a Micro-Electro-Mechanical System (“

MEMS”

), the control circuit comprising;

a variable capacitor having a fixed plate and a movable plate disposed in predetermined spatial relationship with respect to the fixed plate;

a switch comprising a source, a drain and a gate, the switch being associated with one of the fixed and movable plates of the capacitor, the switch further being arranged to selectively connect the one of the fixed and movable plates to a voltage source; and

a voltage generator associated with the switch, the voltage generator being configured to control current flow into the one of the fixed and movable plates of the capacitor.

2. The control circuit of claim 1, wherein the source comprises a source beam.

3. The control circuit of claim 2, wherein the gate comprises a gate structure.

4. The control circuit of claim 3, wherein the drain comprises a drain structure.

5. The control circuit of claim 4, wherein at least one of the drain structure, source beam, and gate structure comprises an aluminum alloy deposited and patterned on a substrate.

6. The control circuit of claim 1, wherein the switch comprises a semiconductor switch.

7. The control circuit of claim 5, wherein the semiconductor switch comprises a substrate, the substrate comprising a silicon layer patterned on its surface.

8. The control circuit of claim 5, wherein at least one of the source, drain, and gate further comprises a non-corroding metal plated on the structural material.

9. The control circuit of claim 4, further comprising a voltage generator configured to apply a voltage between and source and gate to deflect the source beam toward the gate structure.

10. The control circuit of claim 9, wherein the source beam deflects toward the gate structure until establishes electrical contact between the source and the drain.

11. A display device comprising:

a plurality of variable capacitors each having a fixed plate and a movable plate disposed in predetermined spatial relationship with respect to the fixed plate;

a plurality of switches each associated with a selected one of the fixed and movable plates of the capacitors and which is arranged to selectively connect the selected one of the fixed and movable plates with a voltage source; and

a plurality of voltage generators configured to alter current flow into the selected one of the fixed and movable plates of the respective capacitor when the switch is closing.

12. A method of making a control circuit for a Micro-Electro-Mechanical System (“

MEMS”

), the method comprising;

depositing a silicon layer on a substrate;

patterning the deposited silicon layer;

depositing a structural material on the silicon layer;

patterning the deposited structural material to form a source beam, a drain structure, and a gate structure;

plating a non-corroding metal on the deposited structural material; and

etching away at least some of the silicon layer.

13. The method of claim 12, wherein the deposited structural material comprises an aluminum alloy.

14. The method of claim 12, further comprising plating a non-corroding metal on the deposited structural material.

15. The method of claim 14, further comprising etching away at least a portion of the silicon layer.

16. The method of claim 14, wherein the non-corroding metal comprises at least one of gold, iridium, or platinum.

17. The method of claim 16, wherein the plated non-corroding material is configured to maintain a low contact resistance in the control circuit.

18. The method of claim 15, wherein the silicon layer comprises a sacrificial material.

19. A method of making a control circuit for a Micro-Electro-Mechanical System (“

MEMS”

), the method comprising;

forming a variable capacitor having a fixed plate and movable plate disposed in predetermined spatial relationship with respect to the fixed plate;

forming a switch which has a source, a drain and a gate, which is associated with a selected one of the fixed and movable plates of the capacitor and which is arranged to selectively connect the selected one of the fixed and movable plates with a voltage source;

forming a circuit associated with the switch configured to control current flow into the selected one of the fixed and movable plates of the capacitor.

20. A control circuit for a Micro-Electro-Mechanical System, the control circuit comprising:

a variable capacitor having a fixed plate and a movable plate disposed in predetermined spatial relationship with respect to the fixed plate;

means for selectively connecting one of the fixed and movable plates with a voltage source; and

means for controlling current flow into the selected one of the fixed and movable plates of the capacitor.

21. The control circuit of claim 20, wherein the means for selectively connecting one of the fixed and movable plates with a voltage source comprises a switch which has a source, a drain and a gate.

22. The control circuit of claim 21, wherein the means for controlling current flow into the selected one of the fixed and movable plates of the capacitor comprises a circuit associated with the switch.

23. A control circuit for a MEMS (Micro-Electro-Mechanical System) comprising:

variable capacitor means having a fixed plate and movable plate disposed in predetermined spatial relationship with respect to the fixed plate, for operative association with and motivating an arrangement associated with the MEMS;

switch means which has a source, a drain and a gate, which is associated with a selected one of the fixed and movable plates of the capacitor for selectively connecting the selected one of the fixed and movable plates with a voltage source and for inducing a change in distance between the fixed and movable plates;

circuit means associated with the semiconductor switch for attenuating current injection into the selected one of the fixed and movable plates of the capacitor.