An Interferometric Modulator (IMod) is a microelectromechanical device for modulating light using interference. The colors of these devices may be determined in a spatial fashion, and their inherent color shift may be compensated for using several optical compensation mechanisms. Brightness, addressing, and driving of IMods may be accomplished in a variety of ways with appropriate packaging, and peripheral electronics which can be attached and/or fabricated using one of many techniques. The devices may be used in both embedded and directly perceived applications, the latter providing multiple viewing modes as well as a multitude of product concepts ranging in size from microscopic to architectural in scope.

Interferometric modulation of radiation

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.

Photonic mems and structures

A modulator for modulating an incident beam of light, the modulator comprising a plurality of equally spaced-apart elements, each of which includes a light-reflective planar surface. The elements are arranged parallel to each other with their light-reflective surfaces parallel to each other. The modulator includes means for supporting the elements in relation to one another and means for moving particular ones of the elements relative to others so that the moved elements transit between a first configuration wherein the modulator acts to reflect the incident beam of light as a plane mirror, and a second configuration wherein the modulator diffracts the light reflected therefrom. In operation the light-reflective surfaces of the elements remain parallel to each other in both the first and second configurations. The perpendicular spacing between the reflective surfaces of the respective elements is equal to m/4 × the wavelength of the incident beam of light, wherein m equals an even whole number or zero when the elements are in the first configuration and m equals an odd whole number when the elements are in the second configuration.

Method and apparatus for modulating a light beam

Light in the visible spectrum is modulated using an array of modulation elements, and control circuitry connected to the array for controlling each of the modulation elements independently, each of the modulation elements having a surface which is caused to exhibit a predetermined impedance characteristic to particular frequencies of light. The amplitude of light delivered by each of the modulation elements is controlled independently by pulse code modulation. Each modulation element has a deformable portion held under tensile stress, and the control circuitry controls the deformation of the deformable portion. Each deformable element has a deformation mechanism and an optical portion, the deformation mechanism and the optical portion independently imparting to the element respectively a controlled deformation characteristic and a controlled modulation characteristic. The deformable modulation element may be a non-metal. The elements are made by forming a sandwich of two layers and a sacrificial layer between them, the sacrificial layer having a thickness related to the final cavity dimension, and using chemical (e.g., water) or a plasma based etch process to remove the sacrificial layer.

Visible spectrum modulator arrays

One aspect of the invention provides a method for fabricating a microelectromechanical systems device. The method comprises fabricating an array of first elements, each first element conforming to a first geometry; fabricating at least one array of second elements, each second element conforming to a second geometry; wherein fabricating the arrays comprises selecting a defining aspect of each of the first and second geometries based on a defining characteristic of each of the first and second elements; and normalizing differences in an actuation voltage required to actuate each of the first and second elements, wherein the differences are as a result of the selected defining aspect, the defining characteristic of each of the elements being unchanged.

A microelectromechanical systems device and method for fabricating same

A structure and its method for manufacture for a switchable optical filter. The structure comprises a substrate (10) transparent to the radiation of interest, which contains or supports an electrode (12). A spacer layer (16) suspends the membrane over the electrode (12) such that no spacer lies between the electrode (12) and the membrane (22), yet some spacer (16) remains elsewhere to support the membrane (22). The membrane has slots (24) in it which are of a specified length in order to resonate at a particular wavelength of radiation. When the electrode (12) is activated, the membrane (22) deflects and its varying proximity to the substrate changes the wavelength of transmission.

Switchable resonant filter for optical radiation

A spatial light modulator (40,70,80,90,130) operable in the analog mode for light beam steering or scanning applications. A deflectable mirror (42, 72) and which may be hexagonal (92, 132) is supported by a torsion hinge (44,86,94) ends along a torsion axis. A plurality of flexure hinges (48,82,106) are provided to support the ends of the mirror (42,72,92,132) and provide a restoration force. The combination of the torsion hinges and the flexure hinges realizes a deflectable pixel that is operable in the linear range for a large range of address voltages. The flexure hinges also maintain a flat undeflected state when no address voltage is applied, and prevent the pixel from collapsing. The pixel may be reinforced, such as about its perimeter (74) to ensure mirror flatness and prevent warping, even during extreme deflections of the mirror. The pixel is electrostatically deflected by applying an address voltage to an underlying address electrode (60,96,98). The hexagonal mirrors (92,132) allow a tightly packed mirror array, and have a closely circular surface area so as to efficiently reflect a light beam of circular cross section, such as a light beam from fiber optics.

Optical switch having an analog beam for steering light

Metal membranes fabricated using a surface micromachining process can be integrated with passive optical waveguides on silicon substrates to form active devices. Electrostatic actuation of a membrane into contact with a waveguide alters both the real and imaginary parts of the propagation constant of the guided mode. This effect has been used to demonstrate both on-off and routing type integrated optic switches, and has potential application to other devices such as variable attenuators and tunable Bragg filters.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Integrated optic devices using micromachined metal membranes

A fuse and antifuse link structure, which when used with a memory integrated circuit device such as a gate array or programmable mad-only memory (PROM), allows the memory circuit to be reprogrammed. The fuse and antifuse link is comprised of a fuse 12 and an antifuse 16, connected in series, parallel, or a combination thereof. Either element of the link can be programmed initially, and the other can be programmed in a second step, to reverse the first programming. Several links can be used in one circuit to provide multiple reprogramming capability.

Fuse and antifuse reprogrammable link for integrated circuits

A spatial light modulator (40, 70, 80) operable in the analog mode for light beam steering or scanning applications. A deflectable mirror (42, 72) is supported by a torsion hinge (44) along a torsion axis. A plurality of flexure hinges (48) are provided to support the corners of the mirror (42, 72) and provide a restoration force. The combination of the torsion hinges and the flexure hinges realizes a deflectable pixel that is operable in the linear range for a large range of address voltages. The flexure hinges also maintain a flat undeflected state when no address voltage is applied, and prevent the pixel from collapsing. The pixel may be reinforced, such as about its perimeter (74) to ensure mirror flatness and prevent warping, even during extreme deflections of the mirror. The pixel is electrostatically deflected by applying an address voltage to an underlying address electrode (60).

Gregory A. Magel

Papers

Switchable resonant filter for optical radiation

Optical switch having an analog beam for steering light

Integrated optic devices using micromachined metal membranes

Fuse and antifuse reprogrammable link for integrated circuits

Spatial light modulator having an analog beam for steering light