Fluid-based switches such as liquid metal micro switches (LIMMS) are disclosed in the following patents and patent application (the teachings of which are hereby incorporated by reference): U.S. Pat. No. 6,323,447 of Kondoh et al. entitled “Electrical Contact Breaker Switch, Integrated Electrical Contact Breaker Switch, and Electrical Contact Switching Method”; U.S. Pat. No. 6,750,594 of Marvin Glenn Wong entitled “A Piezoelectrically Actuated Liquid Metal Switch”; and U.S. Patent Application of Marvin Glenn Wong entitled “Laser Cut Channel Plate for a Switch” (Ser. No. 10/317,932, filed Dec. 12, 2002).
One way to manufacture the switches disclosed in the above-referenced patent and patent applications is to 1) deposit an adhesive on a channel plate, and then 2) seal the desired combination of switching fluid(s), actuating fluid(s) and/or other switch components between the channel plate and a substrate.
When depositing the adhesive on the channel plate, it is typically desirable to “register” the adhesive with the channels of the channel plate. That is, it is desirable to deposit the adhesive on the channel plate so that it extends precisely up to, but not into, the channels of the channel plate. In this manner, the adhesive does not contribute to increasing or decreasing the volumes of cavities that are defined by the channels when the channel plate is sealed to the substrate.
One aspect of the invention is embodied in a method for depositing material on a channel plate such that the material is registered to one or more channels formed in the channel plate. The method comprises 1) filling at least one of the channels with a resist that is not wetted by the material, 2) depositing the material on at least a region of the channel plate that at least abuts a portion of the resist, the material registering with at least one channel edge as a result of the material's abutment to the resist, and then 3) removing the resist.
Other embodiments of the invention are also disclosed.
Illustrative embodiments of the invention are illustrated in the drawings, in which:
When depositing material on a channel plate, it is sometimes desirable to register the material with one or more channels that are formed in the channel plate. That is, it is sometimes desirable to deposit material on a channel plate such that it extends precisely up to, but not into, the channels of the channel plate.
Fluid-based switches represent one application in which channel registration of a material is desirable. For example, during the manufacture of a switch in accordance with the patent and patent applications disclosed in the Background section of this disclosure, an adhesive may be applied to a channel plate for the purpose of sealing the channel plate to a substrate. Between the channel plate and substrate are sealed a combination of switching fluid(s), actuating fluid(s) and/or other switch components. When depositing the adhesive on the channel plate, it is typically desirable to register the adhesive with the channels of the channel plate so that the adhesive does not increase or decrease the volumes of cavities that are defined by the channels when the channel plate is sealed to the substrate.
One way to register an adhesive with the channels of a channel plate is to deposit a layer of adhesive on the channel plate, partially cure it, deposit a layer of photoresist on top of the adhesive, photodefine the photoresist layer, and then sandblast the adhesive from the channel plate's channels. However, disadvantages of this process include 1) relatively large tolerances in adhesive channel registration, as well as 2) rough channel surfaces as a result of the sandblasting. The process also places limits on the types of substrates that may be used for the channel plate, as well as the geometries of channel structures that can be accommodated.
The inventors have therefore devised new methods for depositing material on a channel plate, as well as new switches that are produced in accordance with the methods. The new methods provide better registration of deposited materials to the channel or channels that have been formed in the channel plate.
For the purpose of this description, “channel” is defined to be any sort of groove, trough, pit or other feature that creates a recess in a channel plate that extends below the uppermost surface of the channel plate.
In accordance with the invention,
Channels 104, 106 may be filled with resist 500 as shown in FIGS. 5 or 6, for example. In
Regardless of how a resist 500 is applied to a channel plate 100, it may be desirable to abrade the channel plate to make the resist 500 planar with the surface of the channel plate 100, or to better define transitions between the resist 500 and the edges of channels 104, 106 that are filled with the resist 500. Following abrasion, the channel plates 100 with resist 500 shown in
By way of example, a channel plate 100 may be abraded by means of chemical mechanical planarization, or grinding and polishing.
Although a channel plate 100 may be abraded solely for the purpose of removing excess resist 500, a channel plate 100 may also be abraded for the purpose of flattening the surface or surfaces of the channel plate bearing resist-filled channels 104, 106. If the material to be deposited on a channel plate 100 is an adhesive or gasket material, flattening the channel plate 100 may help the channel plate 100 achieve a better bond to (or fit with) a part to which it is later mated.
After filling one or more channels 104, 106 with a resist 500, a desired material 800 is deposited 404 (
By way of example, a material layer 800 may be deposited on a channel plate 100 by means of spin coating or spray coating. Since the resist 500 is selected so as not to be wetted by the material 800 that is deposited on the channel plate 100, and as a result of the deposited material's surface tension, the deposited material 800 will only extend up to the borders of the resist 500. Thus, if the resist 500 is precisely registered to the boundaries of a channel plate's channels 104, 106, so too will the deposited material 800 be registered to the boundaries of the channels 104, 106.
After the material 800 has been deposited, the resist 500 may be removed 406 (see
If desired, the channel plate 100, with deposited material 800 thereon, may be mated to another part (e.g., in the case of a fluid-based switch wherein the deposited material 800 is an adhesive or gasket, the part to which the channel plate 100 is mated may be a switch substrate 1200 (
Given that fluid-based switch manufacture is one potential and intended application for the
In one embodiment of the switch 1300, the forces applied to the switching fluid 1318 result from pressure changes in the actuating fluid 1320. The pressure changes in the actuating fluid 1320 impart pressure changes to the switching fluid 1318, and thereby cause the switching fluid 1318 to change form, move, part, etc. In
By way of example, pressure changes in the actuating fluid 1320 may be achieved by means of heating the actuating fluid 1320, or by means of piezoelectric pumping. The former is described in U.S. Pat. No. 6,323,447 of Kondoh et al. entitled “Electrical Contact Breaker Switch, Integrated Electrical Contact Breaker Switch, and Electrical Contact Switching Method”. The latter is described in U.S. Pat. No. 6,750,594 of Marvin Glenn Wong entitled “A Piezoelectrically Actuated Liquid Metal Switch”. Although the above referenced patents disclose the movement of a switching fluid by means of dual push/pull actuating fluid cavities, a single push/pull actuating fluid cavity might suffice if significant enough push/pull pressure changes could be imparted to a switching fluid from such a cavity. In such an arrangement, the channel plate for the switch could be constructed similarly to the channel plate 100 disclosed herein.
The channel plate 1302 of the switch 1300 may have a plurality of channels 102-110 formed therein, as illustrated in
A second channel (or channels 102, 106) may be formed in the channel plate 100 (or 1302) so as to define at least a portion of the one or more cavities 1306, 1310 that hold the actuating fluid 1320. By way of example, these actuating fluid channels 102, 106 may each have a width of about 350 microns, a length of about 1400 microns, and a depth of about 300 microns.
A third channel (or channels 108, 110) may be formed in the channel plate 100 (or 1302) so as to define at least a portion of one or more cavities that connect the cavities 1306-1310 holding the switching and actuating fluids 1318, 1320. By way of example, the channels 108, 110 that connect the actuating fluid channels 102, 106 to the switching fluid channel 104 may each have a width of about 100 microns, a length of about 600 microns, and a depth of about 130 microns.
An exemplary method 1400 for producing the switch 1300 illustrated in
After depositing the material 800, the resist 500 is removed 1408. Optionally, the deposited material 800 may be cured prior to removing the resist 500. Finally, the at least one channel 102-110 formed in the channel plate 100 (or 1302) is aligned with at least one feature on a substrate 1304, and at least a switching fluid 1318 is sealed 1410 between the channel plate 1302 and the substrate 1304, by means of the deposited material 800. As taught in
The material 800 deposited on the channel plate 1302 may be, for example, an adhesive or gasket material. One suitable adhesive is Cytop™ (manufactured by Asahi Glass Co., Ltd. of Tokyo, Japan). Cytop™ comes with two different adhesion promoter packages, depending on the application. When a channel plate 100 has an inorganic composition, Cytop™'s inorganic adhesion promoters should be used and an organic resist 500 should be used. Similarly, when a channel plate 100 has an organic composition, Cytop™'s organic adhesion promoters should be used, and an inorganic resist 500 should be used (including, possibly, an inorganic resist such as a thin sputtered-on coating of metal or glass).
Optionally, and as illustrated in
Additional details concerning the construction and operation of a switch such as that which is illustrated in
Forces may be applied to the switching and actuating fluids 1718, 1720 in the same manner that they are applied to the switching and actuating fluids 1718, 1720 in
The channel plate 1702 of the switch 1700 may have a plurality of channels 102-110 formed therein, as illustrated in
A second channel (or channels 102, 106) may be formed in the channel plate 100 (or 1702) so as to define at least a portion of the one or more cavities 1706, 1710 that hold the actuating fluid 1720.
A third channel (or channels 108, 110) may be formed in the channel plate 100 (or 1702) so as to define at least a portion of one or more cavities that connect the cavities 1706-1710 holding the switching and actuating fluids 1718, 1720.
Additional details concerning the construction and operation of a switch such as that which is illustrated in
The use of channel plates is not limited to the switches 1300, 1700 disclosed in
While illustrative and presently preferred embodiments of the invention have been described in detail herein, it is to be understood that the inventive concepts may be otherwise variously embodied and employed, and that the appended claims are intended to be construed to include such variations, except as limited by the prior art.
This is a divisional of copending application Ser. No. 10/349,712 filed on Jan. 22, 2003, the entire disclosure of which is incorporated into this application by reference.
Number | Date | Country | |
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Parent | 10349712 | Jan 2003 | US |
Child | 10941350 | Sep 2004 | US |