Optics: measuring and testing – By configuration comparison – With comparison to master – desired shape – or reference voltage
Reexamination Certificate
2001-03-22
2003-04-01
Pham, Hoa Q. (Department: 2877)
Optics: measuring and testing
By configuration comparison
With comparison to master, desired shape, or reference voltage
C356S237100, C348S126000, C250S559340
Reexamination Certificate
active
06542236
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an illuminating and optical apparatus for inspecting soldering of a printed circuit board, and more particularly, to the illuminating and optical apparatus which uniformly illuminates and photographs a variety of electronic parts mounted and soldered on the printed circuit board of a surface mounting apparatus to automatically inspect the mounted and soldered states thereof.
BACKGROUND ART
In general, a surface mounting apparatus is used for automatically fixing a variety of electronic parts, such as an integration element, a resistor, a condenser, and the like by directly soldering the electronic parts on the printed circuit board (hereinafter referred to as PCB). That is, without separate soldering lead wires to fix on the PCB, those electronic parts have electrodes for directly soldering the electrodes. In this way, there will be advantages such as reducing the size of electronic parts, substantially improving assembling and manufacturing speed because a separate hole does not have to be formed for fixing electronic parts on the PCB, and decreasing the size of a product.
In soldering various parts with the surface mounting apparatus, the parts are so small that they can not be accurately mounted on the PCB or the amount of solder is so great that the potential may be high for two adjacent electrodes bringing about a lot of errors, such as a short circuit and the like. Therefore, after finishing up soldering parts, mounted and soldered states thereof are inspected to decrease a defective rate of products.
In order to inspect the mounted and soldered states of the parts soldered at the surface mounting apparatus, a number of workers are needed for manual inspection, but it is hard to achieve uniformity of the manual inspection.
Therefore, in case of inspecting the mounted and soldered state of the part soldered on the PCB, an automatic inspection process has been performed by illuminating, and photographing the inspecting parts with a camera and screening the mounted and soldered states of the parts with resultant photographs.
FIG. 1
is a schematic view illustrating an embodiment of a structure and an operational state of a conventional illuminating and optical apparatus which illuminates and photographs mounted and soldered states of an electronic part on a PCB for automatic inspection.
At this time, reference numeral
10
denotes the PCB. Reference numeral
11
denotes an electronic part such as integration element, resistor and condenser and the like of which mounted and soldered states on the printed circuit board are inspected. Also, reference numeral
12
denotes a disturbing part adjacently positioned to the inspecting part soldered on the PCB, which interferes with the proceeding route of the light in inspecting the mounted and soldered states of the part on the PCB.
Reference numerals
13
,
14
, and
15
respectively denote upper, middle and lower light emitting parts, all of which illuminate the inspecting part
11
. All of those light emitting parts are made up of a plurality of lamps arranged in a ring shaped fixtures of different diameters and different heights therebetween.
Symbols H
1
, H
2
, and H
3
, respectively, denote a height of the upper, middle, and lower light emitting parts
13
,
14
,
15
arranged at different heights having the relationship of H
1
>H
2
>H
3
. On the other hand, symbols D
1
, D
2
, and D
3
, respectively, denote a diameter of the upper, middle, and lower light emitting parts
13
,
14
,
15
arranged at different diameters having the relationship of D
1
<D
2
<D
3
.
All of those light emitting parts
13
,
14
,
15
are fixed with an identical center axis.
At this time, for instance, light emitting diodes are used for a plurality of lamps.
Reference numerals
16
,
17
, respectively, denote a camera and lenses positioned over the center axis of all the upper, middle, and lower emitting parts
13
,
14
,
15
for photographing the inspecting part
11
while being illuminated by the upper, middle, and lower light emitting parts
13
,
14
,
15
.
For example, the camera
16
takes a photograph of the inspecting part
11
with a charged coupled device CCD.
When the conventional illuminating and optical apparatus thus constructed is used for inspecting the mounted and soldered states of the part
11
on the PCB
10
, all the lamps of the upper, middle, and lower light emitting parts
13
,
14
,
15
are turned on to illuminate the inspecting part
11
.
At this state, the camera
16
takes an image of the inspecting part
11
illuminated by the upper, middle, and lower light emitting parts
13
,
14
,
15
through the lenses
17
. The photographed image of the inspecting part
10
is inputted and further processed by an inspection apparatus, such as an inspection computer system or the like to inspect the mounted and soldered states of the part
11
on the PCB
10
.
However, in the conventional illuminating and optical apparatus, the incident light of the upper, middle, and lower light emitting parts
13
,
14
,
15
is focused only on a position of the inspecting part
11
, that is, at a center of a photographing view of the camera
16
. As a result, the center of the photographed image is brightest. On the other hand, the closer a position gets to the edge of the image, the image becomes darker.
Therefore, as an image processing condition should be differently set up depending on positions of the same image of an identical inspecting part
11
, it is difficult to make a standard inspection condition.
FIG. 2
is a schematic view illustrating another embodiment of a structure and an operational state of a conventional illuminating and optical apparatus. As shown in
FIG. 2
, the illuminating and optical apparatus includes light diffusers
13
a,
14
a,
15
a
below the upper, middle, and lower light emitting parts
13
,
14
,
15
.
In this case, light illuminated by the upper, middle, and lower light emitting parts
13
,
14
,
15
are diffused by the light diffusers
13
a
,
14
a,
15
a,
thereby relatively evenly illuminating the inspecting part
11
.
However, as the illuminating light is diffused, the amount of light actually directed on the inspecting part
11
has substantially decreased. Therefore, it is difficult to adequately illuminate the inspecting part
11
for inspection. In addition, because the diffusion degree of light varies in response to the quality of a material of the diffuser, it is difficult to evenly illuminate the inspecting part
11
for inspection up to the required level.
Besides the aforementioned problems, there are further problems, which will be de scribed below, in the conventional apparatuses for accurately inspecting the mounted and soldered states of the inspecting part
11
.
First, as only the upper, middle, and lower light emitting parts
13
,
14
,
15
are used for illuminating and photographing the inspecting part
11
, it has been difficult to distinguish a soldering portion of the inspecting part
11
from a pattern of the PCB
10
or the body of the inspecting part
11
, or the electrode of the inspecting part
11
from the body of the inspecting part
11
or the soldering portion. Therefore, it is difficult to simultaneously inspect both, the mounted and soldered states of the inspecting part
Second, if the disturbing matter
12
positioned around the inspecting part
11
is larger than the inspecting part
11
itself, the light emitted by the lower light emitting part
15
tends to be interfered with or blocked by the disturbing matter
12
, causing a light interference phenomenon. Therefore, the required illumination effect can not be obtained, thereby reducing reliability of the inspection process.
Third, there is no control means available for controlling the brightness of the upper, middle, and lower light emitting parts
13
,
14
,
15
, thereby causing inconveniences when in use.
Fourth, a single size of the camera view is available for grasping the inspecting state. In other words, only the camera
16
is utilized at an ident
Pham Hoa Q.
Samsung Electronics Co,. Ltd.
Staas & Halsey , LLP
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