Computer-aided design and analysis of circuits and semiconductor – Nanotechnology related integrated circuit design
Reexamination Certificate
1999-03-10
2002-12-17
Siek, Vuthe (Department: 2768)
Computer-aided design and analysis of circuits and semiconductor
Nanotechnology related integrated circuit design
C716S030000, C716S030000
Reexamination Certificate
active
06496957
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a design evaluating method for assisting a circuit-board-assembly, evaluating assemblability of a circuit board on which electronic components are mounted, a computer-readable recording medium having recorded thereon computer-executable evaluation-assisting programs for executing the design evaluating method for assisting the circuit-board-assembly, and a design evaluating apparatus for assisting the circuit-board-assembly for executing the design evaluating method for assisting the circuit-board-assembly.
It is noted that a term “design and assembly operation,” herein refers to processes ranging from an operation of circuit design and electronic components selection to a completion of engineering-trial manufacture of a component-mounted-circuit board, which is a printed circuit board (which hereinafter may be referred to also as “PCB”) that has electronic components mounted thereon and that fulfills desired functions, on the ground that assembly easiness of electronic components onto the circuit board depends not only on an assembly operation but also, actually, on a process of the circuit design. Therefore, the design evaluation in turn means determining the degree of how design techniques and assembly techniques included in the respective processes ranging from the circuit design to the engineering-trial manufacture of the component-mounted-circuit board as described above are satisfying preset targets of the design techniques and the assembly techniques.
In designing a circuit board that is used in some articles, for example, electronic equipment such as televisions and video cassette recorders and that fulfills desired functions, it has been conventional practice to take such steps as shown in FIG.
86
. That is, after system design for the whole electronic equipment as shown in Step (denoted by “S” in the figure)
1
, the design of circuits capable of executing functions of the system as well as the selection of electronic components to be provided in the circuits are performed based on a system design corpus at Step
2
. Based on circuit diagrams and component lists relating to these circuit design and selected components, circuit board and pattern design is performed at Step
3
. Based on the resulting board design drawings and pattern design drawings, at step
4
, a prototype of a component-mounted-circuit board in which electronic components are mounted on the circuit board is manufactured. At Step
5
, performance evaluation is performed on the prototype component-mounted-circuit board, where if specified performances are satisfied, then the component-mounted-circuit board is trial manufactured. Then, with regard to the prototype, a quality evaluation is performed at Step
7
, a manufacturing cost evaluation is performed at Step
8
, and a production evaluation is performed at Step
9
as to whether or not the protoptype is producible without trouble by a production line, one after,the other based on experiences and the like. If the evaluations of Steps
7
to
9
are all satisfied, then a regular production of the component-mounted-circuit board is started. In addition, if the specified performances are not satisfied in the evaluations of Step
5
and Steps
7
to
9
, then the process flow is fed back to any one of the Steps
12
,
13
and
14
, where the processing steps are executed again starting with the operation of circuit-board redesign and electronic-component reselection, or the redesigning for circuit board and pattern design, or redoing of trial manufacture of the component-mounted-circuit board. In this case, which step among Steps
12
,
13
and
14
the process flow is fed back to is decided based on the results of the performance evaluations.
Like this, in the conventional art, as shown by Step
5
, the assemblability evaluation would not be enabled until the completion of circuit board design and pattern design and the manufacture of the prototype of the component-mounted-circuit board, and as to failures found by the evaluation, the circuit design and the electronic components selection and the like would be redone and a prototype of the component-mounted-circuit board would be manufactured once again.
As shown above, in the conventional art, since the circuit board with electronic components mounted thereon could not be evaluated for its design and manufacture until the circuit board is once completed, there have been problems such as a prolonged design-and-development lead time, a low level of design completeness, and a low productivity and flexibility for variations.
Also, in each of the steps from the operation of circuit design and electronic components selection to the manufacture of the prototype of the component-mounted-circuit board, it has conventionally been practiced that design and manufacture are performed based on personal knowledge and judgment of the design operators or manufacture operators. Thus, in the conventional art, there is no evaluation means for objectively and impartially judging whether or not techniques adopted for the respective steps by the design operator or manufacture operator are the best ones for circuit boards of the system. Neither is there evaluation means which allows a technique that the design operator or manufacture operator is planning to adopt for any one of the steps, to be objectively and impartially evaluated at a planning stage for the adoption of the technique.
In addition, a publication of unexamined Japanese Patent application 4-359497 has disclosed a circuit-board productivity design automatic evaluation system in which it is automatically quantitatively evaluated, prior to the making of a prototype of the component-mounted-circuit board, whether or not the structure of a designed circuit board is easy to produce, and in particular, easy to assemble. However, the invention disclosed in the publication is designed to enable quantitative evaluation of assembly easiness of the circuit board in the stage where the designed circuit board has been forwarded to a manufacturing process. That is, in the invention of the publication, for the evaluation of the assembly easiness without requiring any abundance of experiences, assembling operations in the process of assembling the components onto the circuit board are previously classified into basic factors and correction factors, and then the assembling operations with the circuit board to be evaluated or components are represented by combinations of the basic factors and the correction factors, in which arrangement of the assembly easiness of the circuit board is quantitatively evaluated based on the combinations.
Like this, the invention of the above publication indeed enables the design evaluation prior to the trial manufacture, but is so constituted as to enable the evaluation of the assembly easiness, i.e. productivity design, of the circuit board based on factors relating to the assembling operations, i.e., factors relating to manufacture.
Accordingly, in not only the invention of the above publication but in the conventional art, there exists no one that quantitatively evaluates the assemblability of circuit boards comprehensively by taking into consideration factors other than factors relating to the manufacture, that is, factors relating to the design of the circuit board, factors relating to production technology including manufacturing know-how, and factors relating to manufacture with a manufacturing equipment taken into account, in other words, that quantitatively evaluates the assemblability of circuit boards comprehensively on a scale common to the three divisions of design, production technology and manufacturing.
Further, in the invention of the aforementioned publication, whereas it is considered that the classification into the basic factors and the correction factors is performed based on the experiences of those skilled in the art, whether or not the classification is objectively correct is not determinate, so that the evaluation of the assembly easiness lacks objectivity.
Matsushita Electric - Industrial Co., Ltd.
Siek Vuthe
Thompson A. M.
Wenderoth , Lind & Ponack, L.L.P.
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