Reflectivity, Inc.

Texas Instruments Corporation

Peter Heureux

Satyadev R Patel

Andrew Gerrit Huibers

Andrew Gerritt Huibers

Regis Grasser

Jonathan Clayton Doan

Gregory P Schaadt

Christopher J Spindt

Robert M Duboc

Hongqin Shi

Douglas B MacDonald

Chris Spindt

John K Stockton

To protect the structural layers from being eroded in the etching process, a protection layer is deposited on the exposed structural layers of the micromirror. The protection layer is deposited before etching and removed after etching.

Protection layers in micromirror array devices

Disclosed herein is a micromirror array device that comprises an array of reflective deflectable mirror plates each being associated with one single addressing electrode to be deflected to an ON state angle. A light transmissive electrode is disposed proximate to the mirror plates for deflecting the mirror plates to a non-zero OFF angle. The mirror plates are arranged in the array with a center-to-centre distance of 10.17 microns or less.

Micromirror array device with electrostatically deflectable mirror plates

Disclosed herein is method of operating a device that comprises an array of micromirrors. The method comprises a process usable for repairing stuck micromirrors of the micromirror array during the operation. The reparation process applies, at the ON state, two consecutive refresh voltages to the mirror plates of the micromirrors in the array with the pulses being separated in time longer than the characteristic oscillation time of the micromirrors. The reparation process can be applied independently to the micromirrors. Alternatively, the reparation process can be incorporated with a bias inversion process.

Optical coating on light transmissive substrates of micromirror devices

A micromirror array comprises micromirrors of different properties for use particularly in display systems. Micromirrors of different properties can be arranged within the micromirror array according to a predetermined pattern, or randomly. However, it is advantageous to arrange the micromirrors with different properties within the micromirror array neither in complete order nor complete in random.

Spatial light modulators with non-uniform pixels

The spatial light modulator of the present invention comprises an array of micromirrors, each of which has a reflective deflectable mirror plate. A set of posts are provided for holding the mirror plates on a substrate, but not all micromirrors of the micromirror array have posts.

Micromirror array device and a method for making the same

A spatial light modulator is disclosed, along with methods for making such a modulator that comprises an array of mirror devices each having at least a first electrode and a second electrode. The first electrode is designated for driving the mirror plate of the micromirror device to an ON state, and the second electrode is designated for driving the mirror plate to an OFF state. The two electrodes can be disposed on the same side of the mirror plate but on opposite sides of the rotation axis of the mirror plate for driving the mirror plate to rotate in opposite directions. Alternatively, the two electrodes can be disposed on the opposite sides of the mirror plate, but on the same side of the rotation axis of the mirror plate for driving the mirror plate to rotate in opposite directions. The ON state and OFF state of the mirror plate can be defined by stops. The stops may be formed on substrate(s), hinge structures holding the mirror plates of the micromirror device and/or a desired location within the micromirror device. Alternatively, the electrodes for the ON state and the OFF state can be used as stops, either individually or in combination, or in combination with other component(s), such as substrate(s) of the micromirror device. The OFF state angle and the ON state angle are preferably different.

Micromirrors with OFF-angle electrodes and stops

Disclosed herein is a micromirror-based display system having an improved contrast ratio with the deflection of the micromirrors accomplished through one addressing electrode associate with the micromirror.

Display apparatus with improved contrast ratio

The etching of a material in a vapor phase etchant is disclosed where a vapor phase etchant is provided to an etching chamber at a total gas pressure of 10 Torr or more, preferably 20 Torr or even 200 Torr or more. The vapor phase etchant can be gaseous acid etchant, a noble gas halide or an interhalogen. The sample/workpiece that is etched can be, for example, a semiconductor device or MEMS device, etc. The material that is etched/removed by the vapor phase etchant is preferably silicon and the vapor phase etchant is preferably provided along with one or more diluents. Another feature of the etching system includes the ability to accurately determine the end point of the etch step, such as by creating an impedance at the exit of the etching chamber (or downstream thereof) so that when the vapor phase etchant passes from the etching chamber, a gaseous product of the etching reaction is monitored, and the end point of the removal process can be determined. The vapor phase etching process can be flow through, a combination of flow through and pulse, or recirculated back to the etching chamber. A first plasma or wet chemical etch (or both) can be performed prior to the vapor phase etch.

Method for vapor phase etching of silicon

A micro-mirror that comprises a substrate, a hinge structure formed on the substrate and a mirror plate attached to the hinge structure is provided for use in display systems. The mirror plate is capable of rotating from a non-deflected resting state to a state that is at least 14&#xb0; degrees. In operation, the micro-mirror switches between an 'ON'-state and 'OFF'-state, which are defined in accordance with a rotational position of the mirror plate. The OFF state can be a non-deflected position of the micro-mirror (generally parallel to the substrate), the same angle (though opposite direction) as the ON state, or an angle less than the ON state (though in the opposite direction). Reflected light from the &#x201c;ON&#x201d; and &#x201c;OFF&#x201d; states are thus separated and the contrast ratio is improved.

High angle micro-mirrors and processes

A micro-mirror that comprises a substrate, a hinge structure formed on the substrate and a mirror plate attached to the hinge structure is provided for use in display systems. The mirror plate is capable of rotating from a non-deflected resting state to a state that is at least 14&#xb0;, and preferably from 15&#xb0; to 27&#xb0; from the non-deflected resting state. In operation, the micro-mirror switches between an 'ON'-state and 'OFF'-state, which are defined in accordance with a rotational position of the mirror plate. The OFF state can be a non-deflected position of the micro-mirror (generally parallel to the substrate), the same angle (though opposite direction) as the ON state, or an angle less than the ON state (though in the opposite direction). Reflected light from the &#x201c;ON&#x201d; and &#x201c;OFF&#x201d; states are thus separated and the contrast ratio is improved.

An etching method, such as for forming a micromechanical device, is disclosed. One embodiment of the method is for releasing a micromechanical structure, comprising, providing a substrate; providing a sacrificial layer directly or indirectly on the substrate; providing one or more micromechanical structural layers on the sacrificial layer; performing a first etch to remove a portion of the sacrificial layer, the first etch comprising providing an etchant gas and energizing the etchant gas so as to allow the etchant gas to physically, or chemically and physically, remove the portion of the sacrificial layer; performing a second etch to remove additional sacrificial material in the sacrificial layer, the second etch comprising providing a gas that chemically but not physically etches the additional sacrificial material. Another embodiment of the method is for etching a silicon material on or within a substrate, comprising: performing a first etch to remove a portion of the silicon, the first etch comprising providing an etchant gas and energizing the etchant gas so as to allow the etchant gas to physically, or chemically and physically, remove the portion of silicon; performing a second etch to remove additional silicon, the second etch comprising providing an etchant gas that chemically but not physically etches the additional silicon.

Method for making a micromechanical device by removing a sacrificial layer with multiple sequential etchants

A spatial light modulator having a micromirror and one or more deflection limiting mechanisms, and a process for fabrication therefor. In one embodiment, the mirror support structure has a deflection stopping mechanism that limits the tilt angle of the reflective plate. Alternatively, a deflection stopping mechanism can be provided separate from the mirror support structure. The deflection stopping mechanism can be used in conjunction with one or more additional stopping mechanisms such as the abutment of a portion of the reflective plate against the substrate upon which it was constructed and/or abutment of the micromirror on a surface or structure of the circuit substrate.

Deflectable micromirrors with stopping mechanisms

A spatial light modulator having a substrate holding an array of deflectable (e.g. mirror) elements. The deflectable elements are deflectably coupled to the substrate via corresponding hinges, each hinge being disposed on a side of the deflectable element opposite to the side on which the substrate is disposed. By placing the hinge in this way the fill factor of the array is improved. The hinge can be provided flush against the deflectable element, or it can be provided with a gap between the deflectable element and the hinge. The hinge can be attached via one or more posts or walls connecting to the substrate, and with a flexible or deformable portion that is substantially or entirely hidden from view when viewed through the substrate (e.g. a glass substrate). In one embodiment, the hinge is connected to the undersides of both the substrate and the deflectable element, and connects towards a center part of the deflectable element. In this way, a longer hinge is provided thus reducing strain on any one part of the hinge. Advantages of the present invention include: (1) increased fill factor as the torsion hinge is hidden behind the reflective plate; (2) increased contrast due to fewer scattering optical surfaces exposed, and due to a greater ability to control their angle and geometry; and (3) increased geometric flexibility to optimize electro-mechanical performance and robustness with respect to manufacturing.

Deflectable spatial light modulator having superimposed hinge and deflectable element

A spatial light modulator having one or more deflection limiting mechanisms and process for fabrication therefor. In one embodiment, the mirror support structure has rigid deflection stoppers that limit the tilt angle of the reflective plate. The mirror support structure may also include an attraction electrode that is attached to the back-side of the reflective plate such that the reflective plate may be selectively actuated by electrostatic force. Alternatively, a deflection stopping mechanism can be provided separate from the mirror support structure. The deflection stopping mechanism can be used in conjunction with one or more additional stopping mechanisms such as the abutment of a portion of the reflective plate against the substrate upon which it was constructed. Advantages of the present invention include: (1) increased fill factor as the torsion hinge is hidden behind the reflective plate; (2) increased contrast due to fewer scattering optical surfaces exposed, and due to a greater ability to control their angle and geometry; and (3) increased geometric flexibility to optimize electro-mechanical performance and robustness with respect to manufacturing.

Growing community of inventors

Felton, CA, United States of America

Peter Heureux