Paper B 2018 Fuse for protecting an electronic circuit
Below a short answer to start the discussion.
The DeltaPatents team,
Jelle, Jessica, Nico.
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Brief explanation
Description:
[002]: Two categories: fuses for low-sensitivity electronic components and fuses for high-sensitivity components.
[011] To protect low-sensitivity electronic components quality score Q should be greater than 30. To protect high-sensitivity electronic components quality score Q should be greater than 60.
First conclusion: client wants to provide a fuse for protecting high-sensitivity electronic components [= field].
[009] makes clear that the high quality score is a parameter determined according to an in-house protocol which is not specified in detail. Such a parameter may not be used. It also indicates that a high Q value indicates a low degree of metal reflow.
[004] makes clear that blowing of the fuse should be irreversible. Metal reflow endangers this.
[005] Aim of the invention is to provide a fuse which overcomes that problem.
The purpose is thus to provide an irreversible fuse for high-sensitivity electronic components which avoid/overcome reflow issues.
[005] (part of the solution) using a fuse track formed of AlCu.
Table 1, table 2, [011]: to have Q above 60 we need that the metal of the fuse track is AlCu alloy having a content of Cu in the range of 10-20% by weight and a cover layer made of epoxy resin.
This should be introduced in claim 1 replacing the quality score. It makes original claim 4 redundant.
The cover layer is part of the second embodiment described in [008] for Fig.2. The neck portion is optional and does not need to be incorporated into claim 1 (allowable intermediate generalisation with respect original claim 3.
[012] gives a nice definition of ‘smooth surface’ referring to Ra, better than the active formulation proposed by the client. This should be introduced in original claim 5.
Closest prior art:
Field: high quality fuse for protecting high-sensitivity electronic components
Purpose: provide an irreversible fuse which avoids/overcomes reflow issues
Structurally close: fuse track of AlCu alloy
D1: uses AlCu alloy with 15% Cu by weight, no protective cover. According to table 1: not high quality, not suitable for high-sensitivity electronic components. No further measure to deal with reflow. Conclusion: not close.
D2: Is irreversible (thus high quality), but solves the problem rather differently – not structurally close. The fuse is covered by glass causing an explosion. Reflow issues are thus avoided. Walls are needed to avoid that metal sprays from the fuse to the circuit. Seems not great for high-sensitivity circuits. Conclusion: not close.
D3: uses an AlCu fuse track and focusses on dealing with metal reflow [01]. Close in field and purpose. Structurally close enough.
Conclusion: go for D3 as the closest prior art.
The DeltaPatents team,
Jelle, Jessica, Nico.
===========================================================
Brief explanation
Client's letter
“Our invention has the advantage that the quality score (Q)
of the fuse is much improved”. In draft claim 1 two ‘measures’ are introduced:
- cover layer covering the fuse track
- quality score is at least 60.
Description:
[002]: Two categories: fuses for low-sensitivity electronic components and fuses for high-sensitivity components.
[011] To protect low-sensitivity electronic components quality score Q should be greater than 30. To protect high-sensitivity electronic components quality score Q should be greater than 60.
First conclusion: client wants to provide a fuse for protecting high-sensitivity electronic components [= field].
[009] makes clear that the high quality score is a parameter determined according to an in-house protocol which is not specified in detail. Such a parameter may not be used. It also indicates that a high Q value indicates a low degree of metal reflow.
[004] makes clear that blowing of the fuse should be irreversible. Metal reflow endangers this.
[005] Aim of the invention is to provide a fuse which overcomes that problem.
The purpose is thus to provide an irreversible fuse for high-sensitivity electronic components which avoid/overcome reflow issues.
[005] (part of the solution) using a fuse track formed of AlCu.
Table 1, table 2, [011]: to have Q above 60 we need that the metal of the fuse track is AlCu alloy having a content of Cu in the range of 10-20% by weight and a cover layer made of epoxy resin.
This should be introduced in claim 1 replacing the quality score. It makes original claim 4 redundant.
The cover layer is part of the second embodiment described in [008] for Fig.2. The neck portion is optional and does not need to be incorporated into claim 1 (allowable intermediate generalisation with respect original claim 3.
[012] gives a nice definition of ‘smooth surface’ referring to Ra, better than the active formulation proposed by the client. This should be introduced in original claim 5.
Closest prior art:
Field: high quality fuse for protecting high-sensitivity electronic components
Purpose: provide an irreversible fuse which avoids/overcomes reflow issues
Structurally close: fuse track of AlCu alloy
D1: uses AlCu alloy with 15% Cu by weight, no protective cover. According to table 1: not high quality, not suitable for high-sensitivity electronic components. No further measure to deal with reflow. Conclusion: not close.
D2: Is irreversible (thus high quality), but solves the problem rather differently – not structurally close. The fuse is covered by glass causing an explosion. Reflow issues are thus avoided. Walls are needed to avoid that metal sprays from the fuse to the circuit. Seems not great for high-sensitivity circuits. Conclusion: not close.
D3: uses an AlCu fuse track and focusses on dealing with metal reflow [01]. Close in field and purpose. Structurally close enough.
Conclusion: go for D3 as the closest prior art.
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