APPARATUS FOR DRIVING MICROMECHANICAL DEVICES

• US 20080191978A1
• Filed: 04/07/2008
• Published: 08/14/2008
• Est. Priority Date: 05/05/1994
• Status: Abandoned Application

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: IDC, LLC
• Inventors: Miles, Mark W.
• Application Number:
  US12/099,057
• Publication Number:
  US 20080191978A1
• Time in Patent Office: Days
• US Class Current: 345/84
• 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 apparatus for driving an electronic device comprising an array of microelectromechanical elements, said apparatus comprising:

an input to receive data; and

a driving circuit coupled to said input and configured to generate a select voltage and data voltages from said received data, and to apply said select voltage to one of rows or columns of said array and to apply a bias voltage to the rest of rows or columns of said array, and to apply said data voltages to the columns, in the case when said select voltage is applied to one of the rows, or to the rows, in the case when said select voltage is applied to one of the columns,

wherein each microelectromechanical element with said select voltage applied is actuated when the difference between the values of the data voltage and the select voltage applied to the element is above a first predetermined level, and is released when the difference between the values of the data voltage and the select voltage is below a second predetermined level, and wherein each element with the bias voltage applied maintain its state.

2. The apparatus of claim 1, wherein the bias voltage is within a hysteresis window of the device.

3. The apparatus of claim 2, wherein the bias voltage is in the middle of the hysteresis window.

4. The apparatus of claim 1, wherein said driving circuit further comprises:

a row driver circuit and a column driver circuit for addressing said device; and

a control circuit configured to send control signals to said row and column driver circuits to select the select voltage, the bias voltage and data voltages to be applied by said driver circuits to rows and columns of said device.

5. The apparatus of claim 4, wherein said row driver circuit is configured to apply one of a finite set of possible voltages to each row which is selected by said control signals, and said column driver circuit is configured to apply one of a finite set of voltages to each column which is selected by said control signals.

6. The apparatus of claim 1, wherein the data voltages comprise two possible values, the select voltages comprise two possible values such that the difference between one of the select voltages and one of the data voltages is above the first predetermined level, the difference between the other of the select voltages and one of the data voltages is below the second predetermined level, and the difference between the other of the select voltages and the other of the data voltages is below the second predetermined level.

7. The apparatus of claim 6, wherein the difference between the other of the select voltages and one of the data voltages is above the first predetermined threshold.

8. The apparatus of claim 1, wherein the select voltages are applied in alternating frames such that voltages of alternate polarity are applied to a selected row in successive frames.

9. The apparatus of claim 1, wherein the select voltages are applied in repetitive passes to at least portions of each one of successive frames.

10. The apparatus of claim 1, wherein the select voltages are applied to different portions of a frame at different rates.

11. The apparatus of claim 1, wherein the first predetermined threshold is about 9 volts and the second predetermined threshold is about 0 volts.

12. The apparatus of claim 1, wherein the select voltages are applied in frames, the select voltages being applied to successive rows in separate portions of each frame.

13. An apparatus for driving an electronic device, said apparatus comprising:

a row driver circuit and a column driver circuit for addressing said device; and

a control circuit configured to send control signals to said row and column driver circuits to select a select voltage, a bias voltage and data voltages to be applied by said driver circuits to rows and columns of said device,

wherein data voltages are applied to the columns, in the case when said select voltage is applied to one of the rows and said bias voltage is applied to the rest rows, or to the rows, in the case when said select voltage is applied to one of the columns and said bias voltage is applied to the rest columns,

wherein actuation of each element with the select voltage applied occurs when the difference between the values of the data voltage and the select voltage applied to the element is above a first predetermined level, and release of the device occurs when the difference between the values of the data voltage and the select voltage is below a second predetermined level lowest, and

wherein each element with the bias voltage applied maintains its state.

14. The apparatus of claim 13, wherein said row driver circuit is configured to apply one of a finite set of possible voltages to each row which is selected by said control signals, and said column driver circuit is configured to apply one of a finite set of voltages to each column which is selected by said control signals.

15. The apparatus of claim 13, wherein the data voltages comprise two possible values, the select voltages comprise two possible values such that the difference between one of the select voltages and one of the data voltages is above the first predetermined level, the difference between the other of the select voltages and one of the data voltages is below the second predetermined level, and the difference between the other of the select voltages and the other of the data voltages is below the second predetermined level.

16. The apparatus of claim 13, wherein the select voltages are applied in frames, the select voltages being applied to successive rows in separate portions of each frame.

17. An apparatus for driving an electronic device, said apparatus comprising:

means for receiving data; and

means for driving the electronic device, the driving means being coupled to the receiving means and configured to generate a select voltage and data voltages from said received data, and to apply said select voltage to one of rows or columns of said array and to apply a bias voltage to the rest of rows or columns of said array, and to apply said data voltages to the columns, in the case when said select voltage is applied to one of the rows, or to the rows, in the case when said select voltage is applied to one of the columns,

wherein each microelectromechanical element with said select voltage applied is actuated when the difference between the values of the data voltage and the select voltage applied to the element is above a first predetermined level, and is released when the difference between the values of the data voltage and the select voltage is below a second predetermined level, and wherein each element with the bias voltage applied maintain its state.

18. The apparatus of claim 17, wherein the driving means comprises a driving circuit.

19. The apparatus of claim 17, wherein the receiving means comprises an input to receive data.

20. The apparatus of claim 17, wherein the data voltages comprise two possible values, the select voltages comprise two possible values such that the difference between one of the select voltages and one of the data voltages is above the first predetermined level, the difference between the other of the select voltages and one of the data voltages is below the second predetermined level, and the difference between the other of the select voltages and the other of the data voltages is below the second predetermined level.