Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
2001-09-17
2004-04-13
Arbes, Carl J. (Department: 3729)
Metal working
Method of mechanical manufacture
Electrical device making
C029S740000, C029S833000, C029S741000
Reexamination Certificate
active
06718630
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an apparatus and method for mounting electric components on a substrate such as a circuit board.
BACKGROUND OF THE INVENTION
Referring to
FIG. 31
, there is illustrated a conventional mounting system generally indicated by reference numeral
1
. In general, the system
1
includes a supply section
2
for supplying electric components, a placement head
3
for receiving a component from the supply section
2
and then mounting the component on a substrate such as a circuit board, a transport unit
4
for transporting the placement head
3
, a recognition device
5
for taking a digital image of the component held by the placement head
3
, a holding section
6
for receiving and holding the substrate onto which components are mounted, and a controller
7
for controlling an entire operation of the system
1
.
In operation of the system
1
, the placement head
3
moves to a predetermined position above the supply section
2
bearing a component supply cassette
11
, for example, with a number of components
12
. A vertically extending vacuum nozzle
13
in the form of a quill supported by the placement head
3
is moved down to receive a component
12
. The placement head
3
is then rotated about a vertical axis, i.e. Z-axis, by an angle controller
14
so that the component is oriented in a predetermined direction. The recognition device
5
takes an image of the component
12
, supported by the nozzle
13
of the placement head
3
, moving past a predetermined position opposing the recognition device
5
. The image is transmitted to an image processor
20
where the image is processed according to a specific image processing technique to determine a position of the component, i.e., its horizontal and/or angular displacement relative to the nozzle. Information indicating the position of the component is transmitted to the controller
7
. Based upon the information, the controller
7
corrects the position of the component. Then, the nozzle
13
is moved above a predetermined placement position of substrate
18
and then down toward the substrate
18
so that the component
12
is mounted on the substrate.
FIG. 32
is a flowchart showing a conventional method for mounting components. In this method, at step S
1101
, nozzle
13
receives component
12
. Then, at step S
1102
, recognition device
5
takes a picture of the component
12
held by the nozzle
13
. The picture is processed at image processor
20
. A position of the component
12
is determined at step S
1103
so as to determine whether the component
12
can be mounted on substrate
18
. If the component
12
is incapable of being mounted on the substrate, the nozzle
13
brings the component to a collect station (not shown) at step S
1106
. Otherwise, horizontal and/or angular displacement of the nozzle
13
is determined at step S
1104
. Using this determined displacement, a horizontal position of the placement head
3
and/or an angular orientation of the nozzle
13
is adjusted. Finally, the component
12
is mounted in position onto the substrate
18
at step S
1105
. During this process, no judgement is made as to whether the nozzle
13
interferes with one or more components already mounted on the substrate
18
.
In the meantime, electric devices are likely to be small sized and light-weight, thereby increasing a density of components mounted on substrate
18
considerably. For example, a clearance between neighboring components of about 1.0 mm×0.5 mm is decreased to about 0.2 mm. Notwithstanding this, each component should be mounted on the substrate so that it does not interfere with another component already mounted on the substrate. To this end, used is a nozzle with a tip end designed to be larger than a small component
12
.
However, where clearance of components is down to about 0.1 mm, for example, a displacement of component
12
relative to nozzle
13
may result in an interference between the nozzle
13
and the component
12
already mounted on the substrate
18
. This is illustrated in
FIGS. 33A and 34B
. In each drawing, illustrated are nozzle
13
and components (
12
,
12
a
) both viewed from a substrate. Specifically, in
FIG. 33A
, the nozzle
13
is shown so that it is angularly inclined relative to the component
12
. In this instance, using an image of the component captured by recognition device
5
and a result obtained by image processor
20
, controller
7
corrects a horizontal and/or angular position of the component
12
relative to the nozzle
13
before mounting of the component
12
so that the component is placed at a predetermined, correct position on the substrate. However, as shown by hatched lines in
FIG. 33B
, a part of the nozzle can result in an interference with another component
12
a
already mounted on the substrate. On the other hand,
FIG. 34A
shows a nozzle and component retained by the nozzle in which the component is horizontally offset from a center of the nozzle. In this instance, as shown in
FIG. 34B
, nozzle
13
is displaced so that the component is mounted at a correct position on the substrate, and this in turn results in an interference with another component
12
a
already mounted on the substrate as shown by hatching.
Although not clearly shown in these plan views, i.e.,
FIGS. 33B and 34B
, since the component has a certain height, interference may be more problematic for a case with a reduced clearance when considering a deviation of height and/or inclination of the component. That is, interference between nozzle
13
and component
12
a
results in another displacement of the component
12
a
. What is worse, component
12
may be damaged, which results in a deterioration and/or malfunction of a circuit.
SUMMARY OF THE INVENTION
Therefore, a purpose of the present invention is to provide an apparatus and method for mounting a component on a substrate, which is capable of mounting the component on the substrate without any interference between a nozzle and a component already mounted on the substrate even when only a small clearance is ensured between components on the substrate due to a requirement of compactness of the components.
To this end, according to the apparatus and method of the present invention, a holder receives a component from a component supply and then places the component on a substrate. In operation, a judgement is made as to whether the holder would make an interference with another component already mounted on the substrate. Then, if the judgement is affirmative, a mounting of the component held by the holder is prohibited. If, on the other hand, the judgement is negative, the component held by the holder is mounted on the substrate.
REFERENCES:
patent: 4706187 (1987-11-01), Arai et al
patent: 4805110 (1989-02-01), Takahashi et al.
patent: 5070589 (1991-12-01), Itagaki et al.
patent: 5339248 (1994-08-01), Fajiwara et al.
patent: 5377405 (1995-01-01), Sakurai et al.
patent: 5501005 (1996-03-01), Onitsuka
patent: 5671527 (1997-09-01), Asai et al.
patent: 0 891 129 (1999-01-01), None
Fukuda Shozo
Hada Junichi
Hattori Yoshiyuki
Imafuku Shigeki
Noudo Akira
Arbes Carl J.
Matsushita Electric - Industrial Co., Ltd.
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