Author: YungChieh Hung (20070627);
recommendation: YehLiang Hsu (20070627).
Note: This article is Chapter 5 of YungChieh Hung’s
PhD thesis “Development of an Innovative Patentbased Design Methodology.”
Chapter 5. Development of the design around algorithm
This section discusses the development
of the design around algorithm and the integration with TRIZ to generate
real engineering design concepts from the design problems suggested by the
design around algorithm. The example of the portable magnetic impact tool (U.S.
Patent 6,918,449) is also
used to illustrate the detailed steps of implementation of the patentbased
design process.
5.1 Purpose of the design around algorithm
As discussed in
Chapter 4, a patent can be expressed as
_{}_{} (5.1)
_{} (5.2)
where A is the design matrix that characterizes
the patent. The components in matrix A
are 0s and 1s representing the relation between functions and technologies of
the patent.
Consider a
series of design matrices of existing patents _{}, i = 1, …, n, to be designed around. The purpose of
the design around algorithm developed in this study is to generate a new design
matrix _{} that is similar
to one of the existing matrices _{}, but does not infringe with any of the existing design
matrices. That is, to generate _{} such that
_{} and _{} (5.3)
where “_{}” means “is similar to”, and “≠” means “does not infringe with”.
Figure 51 shows
the flowchart of the design around algorithm. To start with, the designer must
identify the related patents to be designed around and to collect functions
(DPs in Equation (5.1)) and core techniques (FRs in Equation (5.1)) of each
related patent, as in standard patent analysis. Each patent is then symbolized by a “design matrix”
converted from the DPs and FRs of the patent.
After transferring
the related patents into design matrices, the designer has to assign the
priority of DPs to be designed around. The priority of DPs to be designed
around is given to those having the least influence in design matrix, which are the DPs having the least contribution to
the FRs, and the DPs having minimal interaction with other DPs. The columns and
rows of design matrix are sorted according to the number of nonzero elements.
After the
priorities of DPs are decided, the “design around operation matrices” are
applied to the design matrix to generate a new design matrix which is similar
to but does not infringe with the design matrix of the patent to be designed
around. In this research, four design around operation matrices are proposed.
They are elimination, replacement, integration and decomposition. Note that the
design around operation matrices will be applied to the DPs which were assigned
highest priority to be designed around.
The design around operation matrices are applied in the order of “elimination”
(to eliminate redundant component), “replacement” or “integration” (to make at least one constitutive DP substantially
different), and “decomposition” (to replace a multifunctional technological
characteristic with a few separate technological characteristics). New design
matrices which do not infringe with the existing patents and the corresponding
design problems are generated.
Based on the existing patent, TRIZ is used to
transform the new design matrix back into a real engineering design concept. However, this transformation may fail because there may not be a
feasible design corresponding to the new design matrix generated by the
algorithm. If TRIZ fails to generate a feasible design, the algorithm is
triggered again to apply the design around operation matrices to the second
priority DPs. Finally, the process terminates when a feasible new design
concept is generated.
Figure 51. Flowchart of the design around
algorithm (New design matrices which do not infringe upon…)
5.2 Design around strategies
The judgment of infringement
in patent lawsuits consists of three rules: the “all elements rule”, “doctrine of equivalents”, and “doctrine
of file wrapper estoppel”. The first two judgments are
commonly used to make sure whether or not a new design concept infringes with
the original patents.
(1)
All elements rule
If all elements of claims can be literally read on
the components that appear in the accused subject matter, the all elements rule
is satisfied with a literal infringement. In other words, the infringement occurs
if the accused subject matter contains all of the elements that constitute the
claim.
(2)
Doctrine of equivalents
If the all elements rule is not satisfied, but the
elements in the accused subject matter use substantially the same way as those
in the claims, perform substantially the same function, and obtain
substantially the same result, the techniques under investigation are
considered to be equivalent to those in the claims. This is also known as the “triple
identity (way/function/result) test”.
According to the
“all elements rule” and “doctrine
of equivalents”, five strategies of designing around can be recommended
according to the constitutive requirements of patent infringements:
(1)
Eliminate one or more
technological characteristics
This strategy
is applied by using the concept of the all elements rule. One or more of the listed
technological characteristics of an existing patent are eliminated considering
their necessities or strategy of product development.
(2)
Replace one or more of claimed
technological characteristics
This strategy
is considered based on the doctrine of equivalents used in the process of
patent infringement judgment. The implementation of this strategy is to replace at least one technological characteristic of
prior art or other patents.
(3)
Change the functions or
objectives of technological characteristics
This strategy
is also considered based on the doctrine of equivalents. Designing around will be
successful if one or more functions or objectives of unclaimed technological
characteristics are not substantially the same as those of corresponding
claimed ones.
(4)
Integrate two or more claimed
technological characteristics
This strategy
is also considered based on the all elements rule. The purpose of the integration of technological
characteristics is to reduce at least one constitutive element of a claim while
all functions are kept. This kind of integration should not be the simple
combination of original claimed technological characteristics. The means or
operation principles of the specific function must be substantially different
from those of claims.
(5)
Decompose one technological characteristic into multiple technological
characteristics
This strategy
is applied by using the concept of the doctrine of equivalents. This strategy
is opposite of strategy (4). The implementation of this strategy tries to replace a multifunctional technological
characteristic with a few separate technological characteristics.
Table 51 summarizes the five design around strategies. The strategy “change the functions or objectives of
technological characteristics” results in designs of
different functions, therefore is not used in the design around algorithm
developed here. The other
4 design around strategies, elimination, replacement, integration, and
decomposition are considered in the design around algorithm discussed in the
next section.
Table 51. Design around strategies
Design around strategy

Original
patented technological characteristics→Technological characteristics
after designing around

Note

Elimination

_{}→_{}


Replacement

_{}→_{}

Technological
characteristics:
_{}
Function: _{},
_{}

Change

_{}→_{}

Technological
characteristics:
_{}, _{}
Function: _{}, _{}

Integration

_{}→_{}

_{}has the same function as _{}

Decomposition

_{}→_{}

Decompose the function of _{}into_{}and_{}

5.3 Assigning priority to DPs to be designed around
Equation (5.4)
shows the design matrix representation of U.S. Patent 6,918,449,
_{} (5.4)
There are 7 DPs
in this patent. The priority of DPs to be designed around is given to those
having the least influence in A,
which are the DPs having the least contribution to the FRs, and the DPs having
minimal interaction with other DPs. To assign the priorities, the columns of
design matrix A are sorted according
to the number of nonzero elements. Then the rows of design matrix A are sorted according to the number of
nonzero elements.
In Equation
(5.4), the design matrix A remains
unchanged after sorting. _{} only contribute
to one function _{}, and _{}and _{} only contribute
to one function _{}. _{} and _{} only interact
with each other, while _{} interacts with 4
other DPs (_{}, _{}, _{} and _{}) to achieve function _{}. Therefore _{}_{ }and _{} have the highest
priority to be designed around, and _{} has the second
highest priority to be designed around. _{}, _{}, _{} and _{}_{ }are
considered lastly.
5.4 The design around operation matrix
After the
priorities of DPs are decided, the “design around operation matrix” D is applied on the design matrix to
generated a new design matrix _{}:
_{} (5.5)
where _{} is called the “expansion
matrix” of A, defined as
_{} (5.6)
and c is the number of
expanded columns. Note that the patent represented by design matrix A is equivalent to that represented by
design matrix _{}, that is, A=_{}. For example,
_{}_{}
_{} (5.7)
The expansion
matrix will be needed when new DPs are introduced in the design around process.
Finally, the 4 design around strategies discussed in the previous section are
converted into different design around operation matrices.
5.4.1 Elimination
If one or more
components in concerned patent are found to be redundant, they can be eliminated
directly to generate a solution with simplified components/functions. For
example, in U.S. Patent 6,918,449, in order to avoid falling into the scope of all elements rule, eliminating the
magnetic bypass device (_{}) or the changing device (_{}) can be
considered first. Equation (5.4) shows the design
matrix representation of U.S. Patent 6,918,449, where
A=_{} (5.8)
Let
D_{1}=_{} (5.9)
_{} (5.10)
Clearly _{}, because _{}_{ }has
been eliminated, and the designing around is successful according to the all
element rule. The new design can be expressed as
_{} (5.11)
_{} (5.12)
As shown in
Equation (5.12), there is a new design problem to be solved (_{}), which can be translated into:
Design problem 1: “How to design a transformation _{} to achieve the
function _{} (change magnetic flux) using component _{} (changing
device)?”
The same process can be used for eliminating _{}. Let
D_{2}=_{} (5.13)
_{} (5.14)
Clearly _{}, because _{}_{ }has
been eliminated, and the designing around is successful according to the all
element rule. The new design can be expressed as
_{} (5.15)
_{} (5.16)
As shown in
Equation (5.16), there is a new design problem to be solved (_{}), which can be translated into:
Design problem 2: “How to design a transformation _{} to achieve the
function _{} (change magnetic flux) using component _{} (magnetic bypass
device)?”
5.4.2 Replacement
“Replacement”
means one or more components of the design matrix can be displaced by another
component(s). The replacement does not take place haphazardly but reasonably.
For example, in U.S. Patent 6,918,449, in order to avoid falling into the scope of doctrine of equivalents, replacing the magnetic bypass device (_{}) or the changing device (_{}) can be
considered first. A new DP will be introduced in the replacement operation,
therefore the expansion matrix of A is used:
_{} (5.17)
To replace DP6
with DP8, let
D_{3}=_{} (5.18)
_{} (5.19)
The
technological characteristics of _{}_{ }must be
different from those of _{}, so that _{}, and the designing around is successful according to the doctrine of equivalents. The new design can be expressed as
_{} (5.20)
_{} (5.21)
As shown in
Equation (5.21), there is a new design problem to be solved (_{}), which can be translated into:
Design problem 3: “How to design a transformation _{} and a new
component _{} to achieve the function_{} (change
magnetic flux) using component _{} (changing device)
and _{}, while the technological characteristics of _{} are different from those of _{}.”
The same process can be used for replacing _{}. Let
D_{4}=_{} (5.22)
_{} (5.23)
The
technological characteristics of _{}_{ }must be
different from those of _{}, so that _{}, and the designing around is successful according to the doctrine of equivalents. The new design can be expressed as
_{} (5.24)
_{} (5.25)
As shown in
Equation (5.25), there is a new design problem to be solved (_{}), which can be translated into:
Design problem 4: “How to design a transformation _{} and a new
component _{} to achieve the
function_{} (change
magnetic flux) using component _{} (magnetic bypass
device) and _{}, while the technological
characteristics of _{} are different from those of _{}.”
5.4.3 Integration
As discussed
earlier, “integration” combines two or more different components, and the technological
characteristics of the resulting
design are substantially different from those of original components. For example, in U.S. Patent 6,918,449, in order to avoid patent infringement by the all elements rule, the
new product can be obtained through integration of the two technological characteristics of _{} and _{}. Again a new component will be
introduced in the integration operation, therefore the expansion
matrix of A is used:
_{} (5.26)
To integrate _{} and _{} into _{}, let
D_{5}_{} (5.27)
_{} (5.28)
Clearly _{}, because _{} and _{}_{ }have
been integrated into _{}, and the designing around is successful according to the all
element rule. The new design can be expressed as
_{} (5.29)
_{} (5.30)
As shown in
Equation (5.30), there is a new design problem to be solved (_{}), which can be translated into:
Design problem 5: “How to design a transformation _{} to achieve the
function _{} (change magnetic
flux) using a new component _{}, while the technological characteristics of _{} are different from those of _{} and _{}.”
5.4.4 Decomposition
In “decomposition”,
one major component is decomposed into several subordinate components, while the
technological characteristics of the new components are different from those of
the original components. Two or more new components are introduced and the
expansion matrix of A is used:
_{} (5.31)
To decomposed _{} into _{} and _{}, let
D_{6}_{} (5.32)
_{} (5.33)
The
technological characteristics of _{} and _{}_{ }must be
different from those of _{}, so that _{}, and the designing around is successful according to the all element rule. The new design can be expressed as
_{} (5.34)
_{} (5.35)
As shown in
Equation (5.35), there is a new design problem to be solved (_{}), which can be translated into:
Design problem 6: “How to design a transformation _{} and two new
components _{} and _{} to achieve the
function_{} (change
magnetic flux) using two new components _{} and _{}, while the technological
characteristics of _{} and _{} are different from those of _{}.”
To decomposed _{} into _{} and _{}, let
D_{7}_{} (5.36)
_{} (5.37)
The
technological characteristics of _{} and _{}_{ }must be
different from those of _{}, so that _{}, and the designing around is successful according to the all element rule. The new design can be expressed as
_{} (5.38)
_{} (5.39)
As shown in
Equation (5.39), there is a new design problem to be solved (_{}), which can be translated into:
Design problem 7: “How to design a transformation _{} and two new
components _{} and _{} to achieve the
function_{} (change
magnetic flux) using two new components _{} and _{}, while the technological
characteristics of _{} and _{} are different from those of _{}.”
After applying the 4 design around operation
matrices to the components with the highest priority to be designed around, 7
new design matrices, and therefore 7 new design problems are generated. In the
following section, TRIZ is used to find real engineering design concepts that
solves these new design problems.
5.5 Generate real engineering design concepts using TRIZ
5.5.1 Solving design problem 5
In this section, the contradiction matrix and the inventive
principles of TRIZ are used to solve these new design problems. For example,
Design problem 5: “How to design a transformation _{} to achieve the
function _{} (change magnetic
flux) using a new component _{}, while the technological characteristics of _{} are different from those of _{} and _{}.”
The contradiction matrix in the TRIZ
theory contains 39 design parameters and 40 inventive principles for
solving related engineering design problems. As shown in table 52. the
designer searches in 39 design parameters to find the ones matching with the
functions in the design problem, and the “inventive principles” appear
in the corresponding bracket are the possible guidelines to generate the “transformation”.
For design problem 5 described above, Parameter 10 (force) is selected as the feature for achieving the function of “changing magnet
flux” by _{}. In the mean time, we hope that it is easy for _{} to change
magnetic flux. Therefore Parameter 33 (ease of operation) is selected as the feature not to be deteriorated
in Table 52.
As shown in Table 52, four inventive
principles can be obtained. They are Principle 1 (segmentation), Principle 28
(Mechanical interaction substitution), Principle 3 (local quality), and
Principle 25 (selfservice).
Table 52. The contradiction matrix
Undesired result
Feature to change

1

…

33

…

39

Weight of moving
object

…

Ease of operation

…

Productivity

1

Weight of moving
object






…

…






10

Force



1, 28, 3, 25



…

…






39

Productivity






After reviewing the four principles, Principle 28
was utilized to generate the new concept in the portable magnetic impact tool. In TRIZ, Principle 28 has four explanations:
a.
Replace
a mechanical system with an optical, acoustical, thermal or olfactory system.
b.
Use
an electric, magnetic or electromagnetic field to interact with an object.
c.
Replace
fields that are: stationary with mobile, fixed with changing in time, random
with structured.
d.
Use
fields in conjunction with ferromagnetic particles.
In particular, we decided to apply “use an electric, magnetic or electromagnetic
field to interact with an object” to solve the new design problems.
In the new design concept, the new component_{}consists of four solenoids. The four
solenoids are mounted on the magnetic anvil, and the impact torque can be
changed by varying the distribution ratio of the magnetic flux by operating a switch for setting the output of the electric
current value. In this
concept, the new component_{} has already integrated the function of the changing device
and the magnetic bypass device.
5.5.2 Solving design problem 4
Use design problem 4
in Section
5.4.2 as
another example,
“How to design a transformation _{} and a new
component _{} to achieve the
function_{} (change
magnetic flux) using component _{} (magnetic bypass
device) and _{}, while the technological
characteristics of _{} are different from those of _{}.”
For design problem 4 described above, Parameter 10 (force) is selected as the feature for achieving the function of “changing magnetic
flux” by _{}. In the mean time, we hope to increase efficiency of magnetic flux by the _{}. Therefore Parameter 21 (performance) is selected as the feature not to be deteriorated
in Table 53.
As shown in Table 53, four inventive principles
can be obtained. They are Principles 19 (periodic action), Principles 35
(transformation of physical and chemical states of an object), Principles 18
(mechanical vibration), and Principles 37 (complexity of control).
Table 53. The contradiction matrix
Undesired result
Feature to change

1

…

21

…

39

Weight of moving
object

…

Performance

…

Productivity

1

Weight of moving
object






…

…






10

Force



19, 35, 18, 37



…

…






39

Productivity






After reviewing the three principles, Principle 19
was utilized to generate the new concept in the portable magnetic impact tool. In TRIZ, Principle 19 has three explanations:
a.
Replace
a continuous action with a periodic one (impulse).
b.
If
an action is already periodic, change frequency.
c.
Use
pauses between impulses to provide additional action.
In particular,
we decided to apply “replace
a continuous action with a periodic one” and “use pauses between impulses to provide
additional action” to solve the new design problems.
In the new
design concept, the new component _{} consists
of two induction coils. This new component _{} and magnetic bypass device (_{}) are mounted on magnetic anvil (_{}). The electromagnetic anvil is positioned at 180 degrees relative to each other. When a
voltage is applied to the induction coils, it produces a magnetic field. The
force of the induction coil’s magnetic field attracts the magnetic hammer. By
changing the voltage, the
intensity of the magnetic field can be changed.
The function of
impact torque in this new design concept is explained in Figures 52(a) ~ 52(c).
In these figures, only a magnetic hammer and an electromagnetic
anvil are illustrated to simplify the explanation. Referring
to Figure 52 (a), a small clockwise rotation of the hammer (for example, 5 degrees)
makes the hammer attracted magnetically towards the forward anvil. Under the
torque of magnetic attraction, voltage is applied to the solenoid and the hammer
accelerates towards the forward anvil. In Figure 52 (b), the shifting angle formed
between the hammer and the anvil is equal to zero. At this angle, magnetic
field lines emanating from the anvil travel through the ferromagnetic material
of the corresponding hammer to complete the magnetic circuit. Accordingly, the hammer
is at a stable equilibrium, being attracted strongly to the anvil. Note that the voltage
is still applied to the solenoid during their action. Referring to Figure 52 (c), if
the hammer rotates slightly in a clockwise direction (for example, 5 degrees),
the hammer feels a pull towards the anvil due to magnetic attraction. If the electric current in the solenoid is briefly cut off, the magnetic attraction torque is reduced, establishing the magnetic
impact condition.
Figure 52. The operation of the new design
concept
Note that, the _{} (changing device)
in U.S. Patent 6,918,449 comprises a micromotor, a worm
gear and a pinion gear. In the new design concept, _{} consists of two
induction coils. Therefore, the technological characteristics of _{} are different
from those of _{}, and the designing around is
successful according to the doctrine of equivalents.
5.5.3 Discussions
The designer can
try to find solutions for other design problems utilizing TRIZ. However, a good engineering design
concept cannot be generated “automatically” by TRIZ. It still depends on the
domain knowledge and experience of the designer. Moreover, transformation from a design matrix to an engineering design concept
may fail because there may not be a feasible design corresponding to the new
design matrix generated by the algorithm. For example, referring to the Section 5.4.1,
Design problem 2: “How to design a transformation _{} to achieve the
function _{} (change magnetic flux) using component _{} (changing
device)?”
This transformation fails, because the component _{} only performs the function “move magnetic
bypass device”, it is unable to change magnetic flux by itself.