Note: Descriptions are shown in the official language in which they were submitted.
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MULTIAXIAL TRANSDUCER INTERCONNECTION APPARATUS
BACKGROUND OF THE INVENTION
I. Field of the Invention: The invention is directed
generally to a multiaxial interconnection apparatus for transducers
and, more particularly, to a multiaxial transducer interconnection
apparatus for use in advanced rate adaptive cardiac pacemaker
systems, defibrillators, cardioverters, heart monitors, metabolic
need indicators and similar medical electronic devices.
II. Discussion of the Prior Art: Heart and respiration
activity generates mechanical energy. This energy propagates
through the body and can be detected by appropriate transducers and
may provide information useful for the control of organ functions
such as heart rate pacing, for example. Current transducer
technology does not address certain critical aspects of such
medical electronics applications.
Some prior approaches in the medical electronics art use
active (piezoelectric) transducer elements which are well known
such as Bruel & Kjaer Company's Type 4321 and Endevco Company's
Model 2258-10/-100 devices. These devices are limited in their
application, however, because they do not utilize the cost and size
advantages of micromachining technology.
Passive transducers are also known in the prior art.
Passive transducers require excitation energy to operate. In the
case of a multiaxial transducer, the number of supply lines is
proportional to the number of uniaxial transducer components
assembled together. The reduction in quantity of transducer
terminals or wires is critical for many applications. A number of,~
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companies offer passive (piezoresistive) transducers such as IC
Sensors, 1701 McCarthy Boulevard, Mulpitas, CA, for example. These
devices are sensitive in one dimension only, but could be
integrated into a multiaxial transducer. However, it is believed
that the die substrates currently utilized in the industry, have no
designed-in features to aid in substrate-to-substrate electrical
connection.
This invention provides a multiaxial transducer, useful for
medical electronics applications, comprising transducer elements
mounted on electrically interconnected modular substrates. The
multiaxial transducer of the invention achieves a reduction in the
quantity of terminals required for many applications as compared to
other known devices.
SUMMARY OF THE INVENTION
A multiaxial transducer interconnection apparatus. The
apparatus comprises first, second and third substrate modules each
having a plurality of electrical tracks thereon. A portion of the
electrical tracks is structured and arranged to interconnect the
substrate modules in an orthogonal relationship to each other. The
plurality of tracks on each substrate module is further arranged to
form a pattern identical to the plurality of tracks on the other
substrate modules. The substrate modules each include a mounting
region whereon transducer die elements are mounted. The apparatus
disclosed in the invention may be used in an improved advanced rate
adaptive heart pacemaker system including a multiaxial transducer
as disclosed by the invention as a sensing component of such a
system.
One alternate embodiment of the invention includes a base
upon which the modules mount. Another alternate embodiment of the
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invention employs a chip carrier to support the multiaxial
transducer of the invention.
OBJECTS OF THE INVENTION
It is one object of the invention to provide a multiaxial
transducer comprising transducer elements mounted on substantially
identically fabricated substrates.
It is another object of the invention to provide a substrate
assembly for a multiaxial transducer including a plurality of
transducer dies having die bonding pads wherein the ratio of
substrate bonding pads per die bonding terminals is equal to or
greater than three and wherein the location of the substrate
bonding pads allows for pad-to-pad electrical connections of
substrate modules.
It is yet another object of the invention to provide a
lS multiaxial transducer for use as a sensing element on an advanced
rate adaptive cardiac pacer system.
It is yet another object of the invention to provide a
multiaxial transducer assembly fabricated from identical substrate
elements so as to allow use of identical masks for the basic
substrate module fabrication.
Other features, objects and advantages of the invention will
become apparent to those skilled in the art through the description
of the preferred embodiment, claims and drawings herein.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings like numerals refer to like elements.
Figure 1 shows a plan view of one embodiment of a die
substrate module as provided by the invention.
Figure 2 shows a plan view of the interconnection scheme of
one embodiment of the invention.
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Figure 3 shows a perspective view of one embodiment of the
multiaxial transducer of the invention.
Figure 4 is a diagram of the substrate module of the
invention illustrating pad usage.
Figure 5 shows a perspective view of an alternate embodiment
of the multiaxial transducer of the invention including a base
element for supporting the substrate modules.
Figure 6 shows a perspective view of another alternative
embodiment of the multiaxial transducer of the invention employing
a chip carrier.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to Figure 1, a plan view of one embodiment of
a die substrate module as provided by the invention is shown. The
die substrate module 100 comprises a substrate material upon which
printed circuit tracks 102 for carrying electrical power or signals
are deposited by means well known in the art. In one example of an
embodiment of the invention, the substrate module 100 includes
tracks 1, 2, 3 and 4. Track 1 is a negative voltage power line,
track 4 is the positive voltage potential power line, 2 is the
first signal line and 3 is a second signal line for carrying
information from the transducer device to other electronics (not
shown). A test pad, T, may advantageously be included. While the
transducer to be used in connection with the invention is not shown
in Figure 1, the mounting surface 106 for the transducer is shown
as part of the substrate module adjacent to the tracks 102 and as
bordered by the corner markings 110. Broken line 112 denotes a
cutting line for removing excess material from some of the modules
prior to assembly as appropriate as shown in Figure 3 and as
described below in detail. The substrate module may be comprised
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of ceramic substrate material, for example, which may be cut by
means of a laser or other cutting device well known in the art.
Referring now to Figure 2, a plan view of an interconnection
scheme of one embodiment of a substrate assembly including three
die substrate modules is shown. Three substrate modules, lOOA,
lOOB and lOOC, are shown arranged for the purposes of illustrating
the interconnections for this embodiment. Each of the modules
lOOA, lOOB and lOOC initially is fabricated identically as a die
substrate module 100. Depending on where the module is to be used,
certain modifications are made by the removal of unwanted material.
Crossed-hatched areas 200A and 200C are advantageously removed
prior to assembly of the three modules into a multiaxial transducer
as shown in Figure 3 by means of laser trimming or micromachine
milling, for example. Note that Figure 2 is intended to be used as
an interconnection illustration only and is not representative of
a manufacturing process step. Each of the substrates lOOA, lOOB
and lOOC includes a mounting surface area. These are denoted as
106A, 106B and 106C, respectively. Transducer die elements 300A,
300B and 300C as shown in Figure 3 are advantageously affixed to
the mounting surfaces prior to assembly of the modules into the
multiaxial transducer. Each of the modules lOOA, lOOB and lOOC
have power and signal lines as described hereinabove with reference
to module 100 in Figure 1.
Referring now to Figure 3, a perspective view of one
embodiment of the multiaxial transducer of the invention is shown.
With continuing reference to Figure 2, it can be seen that the
three substrate modules lOOA, lOOB and lOOC have now been connected
together to form a multiaxial transducer 202. Transducer devices
300A, 300B and 300C have been mounted to mounting surfaces 106A,
106B and 106C, respectively. The removed material is shown for
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reference purposes as 200A and 200C. No material is removed from
module 100B. Modules 100A, 100B and 100C are oriented such that
the mounting surfaces 106A, 106B and 106C abut each other in an
orthogonal relationship. The transducer devices 300A, 300B and
300C have sensitivity axes 302A, 302B and 302C oriented in a
perpendicular relationship for sensing, in this example, energy
propagated in the X, Y and Z directions. Such transducer devices
are well known in the art and may be, for example, accelerometers
of the type as sold by IC Sensors, as for example, its 3000 Series
accelerometer.
Referring now to Figure 4, a diagram of the substrate module
100 is shown wherein each of the pad areas are designated by a
reference numeral for the purposes of further clarifying the
interconnections for the substrate assembly and multiaxial
transducer. Those skilled in the art will recognize that this
example is given by way of illustration and not limitation of the
invention to the configuration shown. The table below defines the
pad designations and module interconnections in accordance with the
reference numerals in Figures 2 and 4.
PAD PAD DESIGNATION
1 Negative Power Supply Die Bond Pad
2 Negative Output Die Bond Pad
3 Positive Output Die Bond Pad
4 Positive Power Supply Die Bond Pad
Substrate Interconnection Pad lOOB # 5 to lOOA # 8
6 Negative Power Supply Interface Wire Bond Pad
7 Substrate Interconnection Pad 100C # 7 to lOOB # 17
8 Substrate Interconnection Pad 100A # 8 to 100B # 5
9 Alternative Pad, same as Pad #10
Negative Output Interface Wire Bond Pad
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11 Positive Output Interface Wire Bond Pad
- 12 Alternative Pad, same as Pad #11
13 Substrate Interconnection Pad lOOB #13 to lOOC #14
14 Substrate Interconnection Pad lOOC #14 to lOOB #13
Positive Power Supply Interface Wire Bond Pad
16 Substrate Interconnection Pad lOOA #16 to lOOC #18
17 Substrate Interconnection Pad lOOB #17 to lOOC #7
18 Substrate Interconnection Pad lOOC #18 to lOOA #16
19 Negative Power Supply Substrate Edge Connection Contact
for an Alternative Uniaxial Device
Negative Output Substrate Edge Connector Contact for an
Alternative Uniaxial Device
21 Positive Output Substrate Edge Connector Contact for an
Alternative Uniaxial Device
22 Positive Power Supply Substrate Edge Connector Contact
for an Alternative Uniaxial Device
T Test Die Bond Pad
The following table enumerates the pad usages and ratios for
the example embodiment of the substrate module of the invention
shown in Figure 4.
Total Pads. . . . . . . . . . . . . . . . . . . . . . . .. 23
A Test Die Bond Pad. . . . . . . . . . . . . . . . .
B Alternative Pads # 9 and 12. . . . . . . . . . . . 2
C Die Bond Pads # 1-4. . . . . . . . . . . . . . . . 4
D Edge Connector Pads # 19-22. . . . . . . . . . . . 4
E Interconnection Pads # 5, 7, 8, 13, 14, 16-18 . . .... 8
F Interface Wire Bond Pads # 6, 10, 11, 15. . . . . 4
Triaxial Transducer Pad Configuration Ratios for this example are:
E / C = 2
(E + F) / C = 3
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(D + E + F) / C = 4
The above ratios would be smaller if E were equal to zero
- thereby providing no substrate interconnections via specially
designed pads. Note that by utilizing a single substrate module
100 and a transducer 300, a unidirectional assembly can be
fabricated utilizing edge connectors 19-22.
Referring now to Figure 5, an alternate embodiment of the
multiaxial transducer of the invention is shown in perspective
view. This embodiment includes transducers 300A, 300B and 300C
mounted to modular substrates 220A, 220B and 220C and further
mounted to base 250. Interconnections are made by means of wire
conductors or tracks 252.
Referring now to Figure 6, yet another alternate embodiment
of the invention is shown including a multiaxial transducer
assembly 260 having transducers 300A, 300B and 300C (not shown)
mounted on an integrated circuit chip carrier 262. Other pins 264
are then brought out from the chip carrier 262 for interfacing with
external electronics. It is believed that this alternate
configuration would be useful for certain applications.
This invention has been described herein in considerable
detail in order to comply with the Patent Statutes and to provide
those skilled in the art with the information needed to apply the
novel principles and to construct and use such specialized
components as are required. However, it is to be understood that
the invention can be carried out by specifically different
equipment and devices, and that various modifications, both as to
the equipment details and operating procedures, can be accomplished
without departing from the scope of the invention itself. Further,
those skilled in the art will recognize that the applications of
the invention are not limited by the medical industry examples
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cited herein, but also have application to other fields utilizing
multidirectional sensing devices, such as the automotive and
aerospace arts.
What is claimed is:
