It is believed that a proper design of graphene—metal composite makes it a promising structural material candidate for advanced micromechanical devices. Waveform profile of the pule-reverse current, SEM images of the electrochemically exfoliated graphene layers on silicon substrate, and TEM image of graphene curled edge with different layer numbers PDF. Interfaces 8 6 View Author Information. Cite this: ACS Appl. Article Views Altmetric -. Citations 6. Supporting Information. Cited By. This article is cited by 6 publications. DOI: Materials Science and Engineering: A , , Due to an extra axis of motion, the apparatus of FIG.
Pads C and E are in communication with a self solder means. Pad H is in communication with the conductive surface of micromirror assembly Pad D makes an electrical contact with substrate , while pads A, B, F and G are in communication with electrodes not shown disposed beneath the double gimbaled micromirror as with double gimbaled micromirror If optical modification of the beam is required, then a second optical element can be introduced as shown in FIG.
In this embodiment, optical element is bonded to a transparent cover plate Cover plate serves many functions. Using solder glass, adhesives, or the like, one can hermetically seal cavity , intersecting groove , and the voids surrounding optical fiber with cover plate Such a seal would protect the delicate beam steering means below from the harshest of environments. In addition, cover plate provides a convenient means for mounting optics, and providing a positive stop for positioning optical fiber along groove , given a sufficiently large fiber diameter. Yet another embodiment of a beam steering device is shown in FIG.
It is functionally similar to the device in FIG. The pad functions and names are identical to the preferred embodiment. This apparatus can also be sealed with a cover plate and use additional optics as with the previous embodiment. Optical path can be traversed in either direction. Many applications of this technology require only a forward propagating optical path, from optical fiber to secondary optical element For example, any of the embodiments discussed could be used as the printing engine in a high speed laser printer, a photographic emulsions laser plotter, a laser mask writing tool, a steerable industrial laser cutting device, or a pen based, full wall laser display to name a few.
By fabricating three such devices side-by-side and supplying each with a different color light, a pen based, full wall color display can be envisioned.
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- 1. Introduction.
A bi-directional optical path can be utilized in applications such as optical switches, industrial robot vision scanners, illuminating and reading from optical drives such as a CD ROM, illuminating and scanning in an optical microscope configuration, and illuminating and reading bar codes. Of course, two devices could be fabricated together where one transmits the optical signal and the other receives it as with laser range finders or optical proximity detectors.
Although these single sided embodiments lack the convenient self alignment feature provided by lower cavity and alignment means , they would most likely be less costly to manufacture due to the single sided photolithographic steps. In FIG. The flaps may be equipped with a self solder means. During deployment of micromirror assembly , flaps , and provide an added measure of resistance as they encounter the walls of cavity on their way down.
As contact is made, the cantilever flap hinges not shown deflect, allowing the flaps to conform to the slop of the walls within cavity The resulting drag adds stability to the deployment process so that any angle between contact and full deployment can be attained. As with the preferred embodiment, once micromirror assembly is at the desired angle, the self soldering means is activated. In this image, a rigid locking flap is anchored to substrate with a cantilever hinge Locking flap is patterned to a predetermined length such that when deployed, the resulting interference with micromirror assembly produces the desired deployment angle.
For deployments of micromirror assembly beyond 32 degrees, an additional vertical tip may be required to secure the mechanical interference. Flap must necessarily lie over micromirror assembly during fabrication, and thus, requires an additional sacrificial and masking layer. In general, a computer calculates the necessary mirror angles and rates, and transmits a request to a multi-channel voltage amplifier The amplifier converts the digital request to a series of properly scaled voltages.
The voltage signals are then communicated to bond pads A-F, for example. Taken together, and make up the electronic control means for driving any embodiment of a hybrid optical multi-axis beam steering apparatus The desired beam steering transfer function is then established between the optical input and the optical output It is noted that input and output can have either a unidirectional or bi-directional beam path, depending on the intended application. The invention, once completely assembled, can then be wire bonded in the usual fashion. Bond wires extend from an external control circuit to pads A-F.
The entire device can then be hermetically encapsulated, taking care not to permit potting resin to enter cavity or cover optical element In accordance with an aspect of the invention a presently preferred fabrication sequence for the hybrid optical beam steering apparatus is set forth below. Define the sacrificial oxide pads with patterned photoresist and a BOE etch.
Oxide isolation pads will be under bond pads A,B,D,E,F, oxide sacrificial pads will be under bar , under mirror , and in position Sputter Ti A for adhesion plus Au A and pattern to form mirror and lines across hinge areas. Mask for lift-off or plate up of Au areas over all lines and pads except across the hinge area and the mirror area.
Deposit two microns of low stress nitride, low stress silicon carbide or anything impervious to BOE. An adhesion layer may be necessary prior to deposition for good bonding to the Au surface. Provide a mask on the top surface which opens areas that will etch down to bare Si or Au pads, plus opens up the full hinge areas. Plasma etch down to bare Si or Au pads leaving A thick cantilever and torsion hinges.
V-groove area is now open. Form an oxide on the walls of cavity using a high temperature steam or oxygen process, a wet electrochemical process, or a wet chemical process. Spray on photoresist and open only over v-groove and open areas around mirror optional. Electrically ground pad C and apply a positive voltage to pad D thereby causing micromirror assembly to fully deploy downward into cavity While maintaining this position, pass current through pads A and F, thereby causing melting of the thermal adhesive or solder.
Year of fee payment : 4. Year of fee payment : 8. Year of fee payment : A method for making the alignment means of an optical apparatus. The apparatus comprising a substrate defining one or more aligned cavities, a primary optical path for accommodating the passage of a light beam, and an upper cavity in the substrate which is aligned to a predetermined degree of precision and in direct communication with the primary optical path.
The beam steering means directs the beam. The hybrid inter-optical alignment precision occurring when a beam steering mechanism is micromachined with respect to a crystallographic orientation of the substrate is used for precise beam steering. SUMMARY An aspect of the invention provides a method and apparatus for precisely steering a beam of light by making use of a hybrid inter-optical alignment precision which occurs when a beam steering mechanism is micromachined with respect to a crystallographic orientation of a substrate.
Begin with double polished silicon wafers having a low resistivity 1 ohm-cm. Open window through nitride over pad C and etch down to bare silicon. Provide a mask on the top surface which opens areas that will etch down to bare Si. Etch A of low stress nitride or low stress silicon carbide etc. Deposit a sacrificial oxide over top of wafer 1 micron.
Open hole on bottom of wafer and plasma etch down to bare Si. Protect the top side with high melting temperature wax and a carrier wafer. Perform a BOE etch to remove sacrificial pad Post-etch clean with a solution of HCl and H 2 O 2. Remove wax and carrier wafer from top of wafer. Wax carrier wafer to bottom of wafer Mask and etch open holes in oxide layer for electrodes and electrode vias on top side of wafer. Sputter a seed layer of Ti A plus Au A on top surface. Mask and electroplate electrodes.
Mask and electroplate, or sputter and pattern solder bars. Remove all oxide blankets and sacrificial pads with a BOE etch. Remove photoresist. Remove wax and carrier wafer from bottom of wafer. Plasma etch cantilever and torsion hinges down to a thickness of approximately A. After removal of current, micromirror assembly is permanently locked into position. Insert optical element means into cavity and cement or self-solder in place. Cement or self-solder primary optical means into groove Cement or self-solder cover plate over cavity Wire bond all pads to electrical control means.
What is claimed is: 1. A method for making an alignment means for aligning an optical element within a cavity comprising the steps of: providing a sacrificial pad disposed on a lower surface of said substrate for delineating the approximate extent of the lower most dimensions of said lower cavity;. USA en.
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WOA1 en. Surface-mounted, fiber-optic transmitting or receiving component having a deflection receptacle which can be adjusted during assembly.
- 1. Introduction!
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USB2 en. Nederlandse Orgnisatie voor toegepast- natuurwetenschappelijk onderzoek TNO. Optical sensor interrogation system a method of manufacturing the optical sensor interrogation system. JPHA en. USB1 en.