U.S. patent application number 10/412858 was filed with the patent office on 2004-10-14 for longitudinal mode solid slug optical latching relay.
Invention is credited to Fong, Arthur, Wong, Marvin Glenn.
Application Number | 20040201906 10/412858 |
Document ID | / |
Family ID | 33097884 |
Filed Date | 2004-10-14 |
United States Patent
Application |
20040201906 |
Kind Code |
A1 |
Wong, Marvin Glenn ; et
al. |
October 14, 2004 |
LONGITUDINAL MODE SOLID SLUG OPTICAL LATCHING RELAY
Abstract
A piezoelectric optical relay array having one or more array
elements. Each array element contains a transparent mirror housing,
located at the intersection of two optical paths. A solid slug is
moved within a channel passing through the transparent mirror
housing by the action of piezoelectric elements. A surface of the
solid slug is wetted by a liquid metal to form a reflective
surface. The solid slug is moved in or out of the transparent
mirror housing to select between the optical paths. When the solid
slug is within the transparent mirror housing, an incoming optical
signal is reflected from the reflective surface of the liquid
metal. The liquid metal adheres to wettable metal surfaces within
the channel to provide a latching mechanism.
Inventors: |
Wong, Marvin Glenn;
(Woodland Park, CO) ; Fong, Arthur; (Colorado
Springs, CO) |
Correspondence
Address: |
AGILENT TECHNOLOGIES, INC.
Legal Department, DL429
Intellectual Property Administration
P.O. Box 7599
Loveland
CO
80537-0599
US
|
Family ID: |
33097884 |
Appl. No.: |
10/412858 |
Filed: |
April 14, 2003 |
Current U.S.
Class: |
359/824 |
Current CPC
Class: |
G02B 6/3574 20130101;
H01H 2029/008 20130101; H01H 57/00 20130101; G02B 6/3578 20130101;
G02B 6/3546 20130101; G02B 6/3582 20130101; H01H 2057/006 20130101;
G02B 6/3538 20130101 |
Class at
Publication: |
359/824 |
International
Class: |
H01H 029/00 |
Claims
What is claimed is:
1. A piezoelectric optical relay array of one or more array
elements, wherein an array element of the one or more array
elements comprises: a first input optical path; a first output
optical path, optically aligned with the first input optical path
to form a direct optical path; a second output optical path
intersecting the first input optical path; a transparent mirror
housing, located at the intersection of the first input optical
path and the second output optical path; a solid slug adapted to
move within a channel passing through the transparent mirror
housing, the solid slug having a planar surface wettable by liquid
metal; a liquid metal volume covering the planar face of the solid
slug to form a reflective surface; a first piezoelectric actuator
operable to move the solid slug within the channel so that it
blocks the direct optical path and completes a reflected optical
path from the first input optical path to the second output optical
path; and a second piezoelectric actuator operable to move the
solid slug within the channel to remove it from the direct optical
path.
2. A piezoelectric optical relay array in accordance with claim 1,
wherein the array element further comprises a metal coating applied
to a portion of the interior of the transparent mirror housing, the
metal coating being wettable by liquid metal.
3. A piezoelectric optical relay array in accordance with claim 2,
wherein the transparent mirror housing is a triangular tube and the
metal coating is applied to the corners of the transparent mirror
housing, the metal coating tending to cause the liquid metal to
form a reflective surface covering the planar surface of the solid
slug.
4. A piezoelectric optical relay array in accordance with claim 2,
wherein the metal coating is applied to the interior of the channel
above and below the direct and reflected optical paths so that
liquid metal fills gaps between the solid slug and the metal
coating and resists motion of the solid slug.
5. A piezoelectric optical relay array in accordance with claim 1,
wherein the first piezoelectric element is operable to move the
solid slug in a first direction by supplying an impulsive force to
a first end of the solid slug and wherein the second piezoelectric
element is operable to move the solid slug in a second direction by
supplying an impulsive force to a second end of the solid slug.
6. A piezoelectric optical relay array in accordance with claim 1,
wherein the array element further comprises a vent opening to and
connecting the ends of the channel, the vent adapted to relieve
pressure in the channel when the solid slug is moved.
7. A piezoelectric optical relay array in accordance with claim 6,
wherein the vent is sized and positioned to dampen the motion to
solid slug.
8. A piezoelectric optical relay array in accordance with claim 1,
wherein the array element further comprises a second input optical
path, optically aligned with the second output optical path.
9. A piezoelectric optical relay array in accordance with claim 8,
wherein the array comprises a plurality of array elements arranged
in a rectangular grid.
10. A piezoelectric optical relay array in accordance with claim 1,
wherein the transparent mirror housing extends substantially the
whole length of the channel.
11. A piezoelectric optical relay array in accordance with claim
10, wherein the transparent mirror housing is coated with a
wettable metal above and below the direct and reflected optical
paths so that liquid metal fills gaps between the solid slug and
the wettable metal coating and resists motion of the solid
slug.
12. A piezoelectric optical latching relay array, comprising: a
plurality of input optical paths; a plurality of first output
optical path, optically aligned with the plurality of input optical
paths to form a plurality of direct optical paths; a plurality of
second output optical paths intersecting the plurality of input
optical path at a plurality of intersections; and at each of
intersection of the plurality of intersections: a transparent
mirror housing; a solid slug moveably located within a channel
passing through the transparent mirror housing, the solid slug
having a planar face wettable by liquid metal; a liquid metal
volume covering the planar face of the solid slug to form a
reflective surface; a first piezoelectric actuator operable to move
the solid slug within the channel so that it blocks a direct
optical path of the plurality of direct optical path and completes
a reflected optical path from an input optical path of the
plurality of input optical path to a second output optical path of
the plurality of second output optical paths; and a second
piezoelectric actuator operable to move the solid slug within the
channel to remove the solid slug from a direct optical path of the
plurality of direct optical paths.
13. A micro-machined piezoelectric optical relay array comprising
in sequence: an upper spacer layer containing a first piezoelectric
element; a first pair of electrical connectors electrically coupled
to the first piezoelectric element; an upper optical path layer
containing a first direct optical path and a first reflected
optical path, the first direct optical path and the first reflected
optical path having an intersection; a middle spacer layer; a lower
spacer layer containing a second piezoelectric element; a second
pair of electrical connectors electrically coupled to the second
piezoelectric element; a transparent mirror housing located at the
intersection of the first direct optical path and the first
reflected optical path; a solid slug wetted by a liquid metal and
moveable positioned within a channel passing through the
transparent mirror housing; wherein, the first piezoelectric
element is operable to move the solid slug to a first position
removed from the first direct optical path and the second
piezoelectric element is operable to move the solid slug to a
second position, within the direct optical path, where it completes
the first reflected optical path by reflecting light from a wetted
surface of the solid slug.
14. A micro-machined piezoelectric optical relay array in
accordance with claim 13, further comprising: an upper seal belt
layer between the upper spacer layer and the upper optical path
layer and containing an upper wettable metal contact; an middle
seal belt layer between the upper optical path layer and the middle
spacer layer and containing a middle wettable metal contact; and a
lower seal belt layer between the middle spacer layer and the lower
spacer layer and containing an lower wettable metal contact;
wherein, in the first position, the solid slug is coupled by the
liquid metal to the wettable metal contacts in the upper and middle
seal belt layers and, in the second position, the solid slug is
coupled by the liquid metal to the wettable metal contacts in the
middle and lower seal belt layers.
15. A micro-machined piezoelectric optical relay array in
accordance with claim 14, wherein the channel passes the upper,
middle and lower seal belt layers and further comprising a pressure
relief vent opening to the channel in the upper seal belt layer and
the lower seal belt layer.
16. A micro-machined piezoelectric optical relay array in
accordance with claim 14, wherein the hollow transparent housing
passes the upper, middle and lower seal belt layers and further
comprising a pressure relief vent opening to the hollow transparent
housing in the upper seal belt layer and the lower seal belt
layer.
17. A micro-machined piezoelectric optical relay array in
accordance with claim 13, wherein the middle spacer layer contains
a second direct optical path and a second reflected optical
path.
18. A micro-machined piezoelectric optical relay array in
accordance with claim 13, wherein the upper optical path layer
contains a plurality of first direct optical paths and a plurality
of first reflected optical paths.
19. A micro-machined piezoelectric optical relay array in
accordance with claim 13, further comprising: an upper circuit
layer positioned on top of the upper spacer layer; a lower circuit
layer positioned below the lower spacer layer, wherein the first
pair of electrical connectors passes through the upper circuit
layer and terminates in a first pair of interconnection pads and
the second pair of electrical connectors passes through the lower
circuit layer and terminates in a second pair of interconnection
pads.
20. A method for selecting between a direct optical path and a
reflected optical path in a piezoelectric optical relay having a
liquid metal coated solid slug moveable by a first piezoelectric
element and a second piezoelectric element, the method comprising:
coupling an input optical signal to an input optical waveguide of
the piezoelectric optical relay, the input optical waveguide being
optically aligned with a first output optical waveguide to form the
direct optical path; if the direct optical path is to be selected:
applying an electrical impulse to the first piezoelectric element
to move the solid slug out of the direct optical path, whereby the
input optical waveguide is optically coupled to first output
optical waveguide; and if the reflected optical path is to be
selected: applying an electrical impulse to the second
piezoelectric element to move the solid slug into the direct
optical path, whereby the input optical signal is reflected from a
surface of the liquid metal coated solid slug into a second output
optical waveguide to complete the reflected optical path.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is related to the following co-pending U.S.
patent applications, being identified by the below enumerated
identifiers and arranged in alphanumerical order, which have the
same ownership as the present application and to that extent are
related to the present application and which are hereby
incorporated by reference:
[0002] Application 10010448-1, titled "Piezoelectrically Actuated
Liquid Metal Switch", filed May 2, 2002 and identified by Ser. No.
10/137,691;
[0003] Application 10010529-1, "Bending Mode Latching Relay", and
having the same filing date as the present application;
[0004] Application 10010531-1, "High Frequency Bending Mode
Latching Relay", and having the same filing date as the present
application;
[0005] Application 10010570-1, titled "Piezoelectrically Actuated
Liquid Metal Switch", filed May 2, 2002 and identified by Ser. No.
10/142,076;
[0006] Application 10010571-1, "High-frequency, Liquid Metal,
Latching Relay with Face Contact", and having the same filing date
as the present application;
[0007] Application 10010572-1, "Liquid Metal, Latching Relay with
Face Contact", and having the same filing date as the present
application;
[0008] Application 10010573-1, "Insertion Type Liquid Metal
Latching Relay", and having the same filing date as the present
application;
[0009] Application 10010617-1, "High-frequency, Liquid Metal,
Latching Relay Array", and having the same filing date as the
present application;
[0010] Application 10010618-1, "Insertion Type Liquid Metal
Latching Relay Array", and having the same filing date as the
present application;
[0011] Application 10010634-1, "Liquid Metal Optical Relay", and
having the same filing date as the present application;
[0012] Application 10010640-1, titled "A Longitudinal Piezoelectric
Optical Latching Relay", filed Oct. 31, 2001 and identified by Ser.
No. 09/999,590;
[0013] Application 10010643-1, "Shear Mode Liquid Metal Switch",
and having the same filing date as the present application;
[0014] Application 10010644-1, "Bending Mode Liquid Metal Switch",
and having the same filing date as the present application;
[0015] Application 10010656-1, titled "A Longitudinal Mode Optical
Latching Relay", and having the same filing date as the present
application;
[0016] Application 10010663-1, "Method and Structure for a
Pusher-Mode Piezoelectrically Actuated Liquid Metal Switch", and
having the same filing date as the present application;
[0017] Application 10010664-1, "Method and Structure for a
Pusher-Mode Piezoelectrically Actuated Liquid Metal Optical
Switch", and having the same filing date as the present
application;
[0018] Application 10010790-1, titled "Switch and Production
Thereof", filed Dec. 12, 2002 and identified by Ser. No.
10/317,597;
[0019] Application 10011055-1, "High Frequency Latching Relay with
Bending Switch Bar", and having the same filing date as the present
application;
[0020] Application 10011056-1, "Latching Relay with Switch Bar",
and having the same filing date as the present application;
[0021] Application 10011064-1, "High Frequency Push-mode Latching
Relay", and having the same filing date as the present
application;
[0022] Application 10011065-1, "Push-mode Latching Relay", and
having the same filing date as the present application;
[0023] Application 10011121-1, "Closed Loop Piezoelectric Pump",
and having the same filing date as the present application;
[0024] Application 10011329-1, titled "Solid Slug Longitudinal
Piezoelectric Latching Relay", filed May 2, 2002 and identified by
Ser. No. 10/137,692;
[0025] Application 10011344-1, "Method and Structure for a Slug
Pusher-Mode Piezoelectrically Actuated Liquid Metal Switch", and
having the same filing date as the present application;
[0026] Application 10011345-1, "Method and Structure for a Slug
Assisted Longitudinal Piezoelectrically Actuated Liquid Metal
Optical Switch", and having the same filing date as the present
application;
[0027] Application 10011397-1, "Method and Structure for a Slug
Assisted Pusher-Mode Piezoelectrically Actuated Liquid Metal
Optical Switch", and having the same filing date as the present
application;
[0028] Application 10011398-1, "Polymeric Liquid Metal Switch", and
having the same filing date as the present application;
[0029] Application 10011410-1, "Polymeric Liquid Metal Optical
Switch", and having the same filing date as the present
application;
[0030] Application 10011436-1, "Longitudinal Electromagnetic
Latching Optical Relay", and having the same filing date as the
present application;
[0031] Application 10011437-1, "Longitudinal Electromagnetic
Latching Relay", and having the same filing date as the present
application;
[0032] Application 10011458-1, "Damped Longitudinal Mode Optical
Latching Relay", and having the same filing date as the present
application;
[0033] Application 10011459-1, "Damped Longitudinal Mode Latching
Relay", and having the same filing date as the present
application;
[0034] Application 10020013-1, titled "Switch and Method for
Producing the Same", filed Dec. 12, 2002 and identified by Ser. No.
10/317,963;
[0035] Application 10020027-1, titled "Piezoelectric Optical
Relay", filed Mar. 28, 2002 and identified by Ser. No.
10/109,309;
[0036] Application 10020071-1, titled "Electrically Isolated Liquid
Metal Micro-Switches for Integrally Shielded Microcircuits", filed
Oct. 8, 2002 and identified by Ser. No. 10/266,872;
[0037] Application 10020073-1, titled "Piezoelectric Optical
Demultiplexing Switch", filed Apr. 10, 2002 and identified by Ser.
No. 10/119,503;
[0038] Application 10020162-1, titled "Volume Adjustment Apparatus
and Method for Use", filed Dec. 12, 2002 and identified by Ser. No.
10/317,293;
[0039] Application 10020241-1, "Method and Apparatus for
Maintaining a Liquid Metal Switch in a Ready-to-Switch Condition",
and having the same filing date as the present application;
[0040] Application 10020473-1, titled "Reflecting Wedge Optical
Wavelength Multiplexer/Demultiplexer", and having the same filing
date as the present application;
[0041] Application 10020540-1, "Method and Structure for a Solid
Slug Caterpillar Piezoelectric Relay", and having the same filing
date as the present application;
[0042] Application 10020541-1, titled "Method and Structure for a
Solid Slug Caterpillar Piezoelectric Optical Relay", and having the
same filing date as the present application;
[0043] Application 10030438-1, "Inserting-finger Liquid Metal
Relay", and having the same filing date as the present
application;
[0044] Application 10030440-1, "Wetting Finger Liquid Metal
Latching Relay", and having the same filing date as the present
application;
[0045] Application 10030521-1, "Pressure Actuated Optical Latching
Relay", and having the same filing date as the present
application;
[0046] Application 10030522-1, "Pressure Actuated Solid Slug
Optical Latching Relay", and having the same filing date as the
present application; and
[0047] Application 10030546-1, "Method and Structure for a Slug
Caterpillar Piezoelectric Reflective Optical Relay", and having the
same filing date as the present application.
FIELD OF THE INVENTION
[0048] The invention relates to the field of optical switching
relays, and in particular to a piezoelectrically activated optical
relay array that latches by means of a liquid metal.
BACKGROUND OF THE INVENTION
[0049] Communications systems using optical signals require the use
of optical switches and routers. An early approach to optical
switching was to convert the optical signal to an electrical
signal, use an electrical switch or router and then convert back to
an optical signal. More recently, optical relays have been used in
which an electrical control signal is used to control the switching
or routing of an optical signal. Optical relays typically switch
optical signals by using movable solid mirrors or by using the
creation of bubbles in liquid. The moveable mirrors may use
electrostatic latching mechanisms, whereas bubble switches do not
latch. Piezoelectric latching relays may either use residual
charges in the piezoelectric material to latch, or actuate switch
contacts containing a latching mechanism.
SUMMARY
[0050] This invention describes an optical relay array that uses a
liquid metal, such as mercury, as a switching mechanism and as a
latching mechanism. The present invention relates to a
piezoelectric optical relay array having one or more array
elements. An array element contains a transparent mirror housing,
located at the intersection of two optical paths. A solid slug is
moved within a channel passing through the transparent mirror
housing by the action of piezoelectric elements. A surface of the
solid slug is wetted by a liquid metal to form a reflective
surface. The solid slug is moved in or out of the transparent
mirror housing to select between the optical paths. When the solid
slug is within the transparent mirror housing, an incoming optical
signal is reflected from the reflective surface of the liquid
metal; otherwise the optical signal passes through the transparent
housing. The liquid metal may also adhere to wettable metal
surfaces within the channel to provide a latching mechanism.
BRIEF DESCRIPTION OF THE DRAWINGS
[0051] The features of the invention believed to be novel are set
forth with particularity in the appended claims. The invention
itself however, both as to organization and method of operation,
together with objects and advantages thereof, may be best
understood by reference to the following detailed description of
the invention, which describes certain exemplary embodiments of the
invention, taken in conjunction with the accompanying drawings in
which:
[0052] FIG. 1 is a top view of an optical layer of an optical relay
consistent with certain embodiments of the present invention.
[0053] FIG. 2 is a side view of an optical layer of an optical
relay consistent with certain embodiments of the present
invention.
[0054] FIG. 3 is a sectional view of an optical layer of an optical
relay consistent with certain embodiments of the present
invention.
[0055] FIG. 4 is a sectional view of an optical relay consistent
with certain embodiments of the present invention.
[0056] FIG. 5 is a sectional view of an optical layer of an optical
relay array consistent with certain embodiments of the present
invention.
[0057] FIG. 6 is a top view of a seal belt layer of an optical
relay array consistent with certain embodiments of the present
invention.
[0058] FIG. 7 is a view of an upper circuit layer of an optical
relay array consistent with certain embodiments of the present
invention.
[0059] FIG. 8 is a sectional view of an upper circuit layer of an
optical relay array consistent with certain embodiments of the
present invention.
[0060] FIG. 9 is a view of a spacer layer of an optical relay array
consistent with certain embodiments of the present invention.
[0061] FIG. 10 is a further sectional view of an optical relay
consistent with certain embodiments of the present invention.
DETAILED DESCRIPTION
[0062] While this invention is susceptible of embodiment in many
different forms, there is shown in the drawings and will herein be
described in detail one or more specific embodiments, with the
understanding that the present disclosure is to be considered as
exemplary of the principles of the invention and not intended to
limit the invention to the specific embodiments shown and
described. In the description below, like reference numerals are
used to describe the same, similar or corresponding parts in the
several views of the drawings.
[0063] The present invention relates to an optical relay that
latches by means of a liquid metal, such as mercury. When a small
volume of liquid metal wets a surface, the surface tension of
liquid metal tends to hold the liquid metal to the surface. In an
optical relay consistent with certain embodiments of the present
invention, a solid slug, wetted with liquid metal, is used to block
or unblock an optical path. Surface tension is used as a latching
mechanism to maintain the position of the liquid metal.
[0064] Piezoelectric materials and magnetorestrictive materials
(collectively referred to as "piezoelectric" materials below)
deform when an electric or magnetic field is applied.
[0065] The relay operates by means of the longitudinal deformation
of a piezoelectric element, in extension mode, displacing a solid
slug that is wettable by a liquid metal drop and causing it to wet
between at least one contact pad on the piezoelectric element or
substrate and at least one other, fixed pad to block the optical
path. The same motion that causes the solid slug and the attached
liquid metal drops to change position can cause the optical path to
be unblocked between the fixed pad and a contact pad on the
piezoelectric element or substrate close to it. This motion of the
piezoelectric element is rapid and causes the imparted momentum of
the solid slug and liquid metal drops to overcome the surface
tension forces that would otherwise hold them in contact with the
contact pad or pads near the actuating piezoelectric element. The
switch latches by means of surface tension and the liquid metal
wetting to the contact pads. The liquid metal attached to the solid
slug can wet to wettable metal elements in the optical path cavity,
thereby creating a mirror effect that can be used to redirect the
optical signal in a different direction.
[0066] In accordance with certain embodiments, the switch is made
using micro-machining techniques to obtain small size. In this
embodiment the switching time is short. For comparison,
piezoelectrically driven thermal inkjet print-heads have firing
frequencies of several kHz and the fluid dynamics afforded by the
present invention is much simpler than in an inkjet print head.
Little heat is generated since the only heat generators are the
piezoelectric element and the passage of control currents through
the conductors of the switch.
[0067] FIG. 1 is a top view of the optical layer of an optical
relay 100 of one embodiment of the present invention. Referring to
FIG. 1, an optical signal enters the relay on the left side and
either transmitted along a direct path through the relay to exit on
the right side, or is reflected inside the relay to exit at the
relay at the bottom in the figure. The section 4-4 is shown in FIG.
4 described below.
[0068] The micro-machined optical relay of the present invention is
made up of a number of layers. FIG. 2 is a side view of the optical
layer of an optical relay 100 of one embodiment of the present
invention. The relay comprises upper and lower circuit substrates
202 and 218, upper and lower piezoelectric layers 204 and 216,
upper, middle and lower seal belt or spacer layers 206, 210 and 214
and upper and lower optical switching layers 102 and 212. Upper and
lower electrical connections 222 and 226 are provided for control
signals. The section 3-3 is shown in FIG. 3 described below.
[0069] FIG. 3 is a sectional view through the section 3-3 of the
optical relay 100 shown in FIG. 2. Referring to FIG. 3, the layer
102 contains a first input optical path or waveguide 103 and a
first output optical path or waveguide 104. These paths are
optically aligned to form a direct optical path through the layer.
A second optical output path or waveguide 106 intersects the direct
optical path. In operation, an optical signal enters path 103 (from
the left in the figure) and either passes directly through the
relay via path 104 or is deflected to exit the relay through path
106. A transparent, hollow tube 108 is located at the intersection
of the paths 104 and 106. The transparent, hollow tube 108 is also
referred to as a transparent mirror housing in the sequel. The axis
of tube is substantially perpendicular to the layer 102. Tubes
having other than triangular cross-sectional shapes may be used,
however, one face of the tube should be planar and angled so that
the normal to the face bisects the angle between the path 104 and
the path 106. In FIG. 3, the paths are at right angles, so the face
is angled at 45.degree.. Other angles may be used without departing
from the present invention. A solid slug of material 110 is
positioned in a channel that passes through the transparent tube
108, and is free to slide axially along the channel. A liquid metal
112 is also contained within the channel. The surface of the solid
slug 110, other than the ends, is wettable by the liquid metal, so
surface tension holds the liquid metal in contact with the surface
of the slug. Where the transparent tube passes through the optical
layer, the corners of the transparent tube are filled with a
wettable metal. The wettable metal 114 in one of the three corners
is shown in FIG. 3. The liquid metal is drawn across the face of
the slug by the surface tension attracting the liquid metal to the
wettable metal in the corners of the tube. As a result, the surface
of the liquid metal is planar and highly reflective. An optical
signal entering the channel 103 is reflected from the surface of
the liquid metal 108 and exits the relay through channel 106. When
the solid slug 110 is moved out of the path of the optical signal,
the optical signal passes through the transparent tube and exits
the relay through channel 104. In operation, the solid slug 110
moves axially along the channel through the transparent tube.
Displaced gas within the channel is allowed to flow from one end of
the channel to the other via a vent 116. Optionally, a second
optical input path 107 may be incorporated, to facilitate coupling
of optical relays in an array.
[0070] FIG. 4 shows a sectional view along the section 4-4 in FIG.
1. The optical relay 100 is made up of a number of layers that may
be formed by micro-machining. An upper circuit layer 202 contains
conductive vias and electrical interconnect pads 222. A spacer
layer 204 includes a piezoelectric element 220. The piezoelectric
element 220 is configured to move in a extensional mode parallel to
the axis of the transparent tube (mirror housing) 108. Electrical
drive signals are supplied to the piezoelectric element 220 through
the conducting vias and electrical interconnect pads 222. An upper
seal belt layer 206 holds the upper end of the transparent tube
108. In this layer, the transparent tube is lined with a wettable
metal 114. Preferably, the wettable metal covers all interior faces
of the transparent tube to form a seal belt or contact. In an
alternative embodiment the transparent tube does not extend into
the seal belt layer, and the wettable metal is applied to the
substrate of the layer. In a still further embodiment, the wettable
metal is applied to the surface of the piezoelectric element. When
the solid slug is at the top of the transparent tube, as shown in
FIG. 4, the liquid metal 112 fills the gaps between the solid slug
110 and the seal belt. Surface tension then holds the solid slug in
place, preventing it from moving within the channel passing through
the transparent tube. The combination of wettable surfaces and
liquid metal provides a latching mechanism for the relay. The vent
(116 in FIG. 3) opens into the seal belt layer 206. The first
optical layer 102 contains an optical path, through which the
transparent tube 108 passes. A middle seal belt layer 210 holds the
middle of the transparent tube 108. In this layer, the transparent
tube is lined with a wettable metal 114, to provide an additional
latching mechanism. The spacer layer 212 may, optionally, contain
additional optical paths. The lower seal belt layer 214 functions
in the same way as the upper seal belt layer. The lower seal belt
layer provides additional latching via lower seal belts 114 when
the solid slug 110 is moved to the lower end of the transparent
tube 108. The lower spacer layer 216 and the lower circuit layer
218 function the same as the corresponding upper layers, 204 and
202 respectively. The section through the optical layer, denoted as
BB in FIG. 2, is shown in FIG. 1.
[0071] FIG. 5 shows a section through the optical layer of an
optical relay array comprising a rectangular grid of optical relay
elements. The embodiment shown in FIG. 5 has nine elements, but
other size arrays may be used. The optical relay array has three
input optical paths 103 and three first output optical paths 104,
which together form three direct optical paths through the layer.
In addition, three second output optical paths 106 are provided,
intersecting the three direct optical paths. A transparent mirror
housing 108 is located at each of the nine intersections. In
accordance with certain embodiments, the housing preferably has a
triangular cross-section. A wettable metal 114 fills the corners of
the transparent mirror housing 108. The wettable metal 114 is
located on either side of the planar face of the housing. Close to
each housing is a pressure relief vent 116, which passes through
the optical layer 102. An input optical signal, entering the relay
at one of the input optical paths 103, may be routed to one of the
second output optical paths 106 by positioning a wetted slug at the
intersection of the input optical path and the output optical path.
The reflective surface of the wetted slug deflects the optical
signal along a second output optical path. Alternatively, if no
wetted slug is present, the input optical signal passes through the
transparent mirror housing 108 and exits the relay from the
corresponding first output optical path 104.
[0072] FIG. 6 is a diagrammatic representation of an embodiment of
an upper seal belt layer 206 of an optical relay array. The layer
contains an array of nine triangular holes 402 through which wetted
slugs may pass. Each hole is lined with a wettable metal seal belt
or contact 114. Optionally, the transparent mirror housing may pass
through the seal belt layer, as shown in FIG. 4, in which case the
wettable metal lines the inside of the transparent mirror housing.
Referring again to FIG. 6, each hole 402 is coupled by a channel
404 to the pressure relief vent 116. The channel 404 allows gas to
flow between the hole and the vent. Middle seal belt layer 210 has
a similar construction, but does not include channels 404. Lower
seal belt layer 214 is also of a similar construction, except that
the channels are on the lower surface of the layer.
[0073] FIG. 7 is a view of the upper circuit layer of an optical
relay array. Interconnection pads of electrical conductors 222 are
located on top of the layer to facilitate connection of the relay
to the electrical signals that control the piezoelectric elements
of the array. FIG. 8 is a sectional view through the section 8-8 in
FIG. 7. This shows how the conductors pass through vias in the
circuit layer and couple to the piezoelectric elements 220. The
electrical conductors couple to the top and bottom surfaces of the
piezoelectric element and operate to supply an electric potential
across the piezoelectric element. The lower circuit layer 218 has a
similar construction.
[0074] An embodiment of a spacer layer of the optical relay array
is shown in FIG. 9. The spacer layer contains an array of holes 702
through which wetted slugs may pass. These holes align with the
corresponding holes in the other layers to form channels. The
channel enables the wettable slugs can pass through the layers to
block or unblock the direct optical paths.
[0075] FIG. 10 is a sectional view through the section 10-10 of the
optical relay array shown in FIG. 6. The cross section is taken
vertically through the pressure relief vents 116 and shows how the
pressure relief vents open to the interior of the transparent
mirror housing 108. Opening 802 in the optical layer 102, and other
corresponding openings in the layer, are found at the intersection
of the input optical paths and the output optical paths. Opening
804 is at a corresponding intersection in the optional lower
optical path in spacer layer 214. For clarity, neither the solid
slugs nor the electrical conductors are shown in FIG. 10. The
pressure relief vents 116 allow gas to pass from one end of the
hollow tube 108 to the other end as the solid slug moves within the
tube. The pressure relief vents 116 also serve to dampen the motion
of the solid slug as gas is forced through the vent.
[0076] While the invention has been described in conjunction with
specific embodiments, it is evident that many alternatives,
modifications, permutations and variations will become apparent to
those of ordinary skill in the art in light of the foregoing
description. Accordingly, it is intended that the present invention
embrace all such alternatives, modifications and variations as fall
within the scope of the appended claims.
* * * * *