Image analysis – Applications – Manufacturing or product inspection
Reexamination Certificate
1998-08-31
2001-03-20
Boudreau, Leo (Department: 2621)
Image analysis
Applications
Manufacturing or product inspection
C250S559340
Reexamination Certificate
active
06205238
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus and a method for inspecting leads of an IC, and more particularly, to an apparatus and a method for precisely and automatically inspecting leads of an IC.
2. Description of the Prior Art
When the intervals between the leads of an IC and arrangement thereof are not even, the leads may get loose from a setting table while they are welded, which may cause a defect in electrical connection thereof. Thus, ICs have to be inspected before being installed on a PCB, and therefore, a variety of methods for inspecting the status of leads of an IC have been proposed.
FIG. 6
is a schematic partial perspective view of an apparatus for inspecting leads of an IC disclosed in U.S. Pat. No. 5,162,866. As shown in the figure, the conventional apparatus
61
for inspecting leads of an IC complises a setting table
57
on which ICs
51
are placed, a supporting part
63
for supporting the setting table
57
, an optical image recognition part
65
disposed above the supporting part
63
, and an image processor (not shown) for implementing the image of an inspection area on the basis of the output signals of the optical image recognition part
65
.
The optical image recognition part
65
inspects the status of leads
53
of the IC
51
placed on the setting table
57
. The optical image recognition part
65
has a laser beam source
67
and an optical sensing element
69
. The laser beam source
67
projects a scan beam toward the IC
51
on the setting table
57
, and the optical sensing element
69
receives the light reflected from the leads
53
of the IC
51
. The optical image recognition part
65
is fixed to an arm
71
, and the arm
71
can be moved horizontally and vertically by a driving device which is not shown.
In the conventional inspecting apparatus
61
having such a construction, when the setting table
57
on which the IC
51
is placed is supported by the supporting part
63
, the optical image recognition part
65
is disposed above the setting table
57
by a manual operation of an operator or by a program stored in a control part. Then, the operator observes the image of the IC
51
implemented on the image processor while moving the optical image recognition part
65
with respect to the setting, table
57
. When a position at which an optimal image can be achieved is detected during the observation, the operator disposed the optical image recognition part
65
on that position. In order to inspect precisely the intervals and arrangement of the leads
53
, it is most important to dispose the optical image recognition part
65
at an optimal position.
Meanwhile, when the optical image recognition part
65
is disposed at the optimal position, the control part (not shown) moves the optical image recognition part
65
along a predetermined scan line. The laser beam source
67
projects the scan beam toward the leads
53
while the optical image recognition part
65
is moving, and the optical sensing element
69
receives the light reflected from the leads
53
. The amount of reflected light received by the optical sensing element
69
valies according to the intervals and the arrangement of the leads
53
, and the optical image recognition part
65
outputs pulses having the amplitude corresponding to the amount of the reflected light received by the optical image recognition part
65
. The image processor implements the image of the leads
53
according to the output signal of the optical image recognition part
65
, so the operator can determine the quality of the leads
53
of the IC
51
.
Meanwhile, another type of apparatus for inspecting leads of an IC has been proposed which can detect the defect thereof automatically by comparing the output signals of the optical sensing element
69
with reference data about the quality of the leads of an IC.
Recently, the electrical appliances become small-sized and performance thereof becomes high, so the size of the IC
51
becomes smaller. Therefore, in order to inspect the intervals and arrangement of the leads
53
of an IC
51
with the conventional inspecting apparatus
61
, the operator has to precisely control the distance between the IC
51
and the optical image recognition part
65
manually. Therefore, the inspection speed is low, and the preciseness of the inspection is lowered.
SUMMARY OF THE INVENTION
The present invention has been proposed to overcome the above-described problems of the conventional art. Therefore it is an object of the present invention to provide an apparatus and a method for inspecting leads of an IC, which can control the distance between the IC and an optical image recognition part automatically so that the intervals and the arrangement of the leads of the IC placed on a setting table can be inspected precisely and quickly.
To achieve the above object, the present invention provides an apparatus for inspecting leads of an IC placed on a setting table, said apparatus comprising: an optical image recognition part disposed above said setting table, said optical image recognition part for projecting a scan beam onto said setting table and receiving a light reflected therefrom; a driving means for moving said optical image recognition part with respect to said setting table; a position detection part for detecting a position of said optical image recognition part on the basis of an output signal of said optical image recognition part; and a control part for controlling said driving means on the basis of a detection signal of said position detection part so that said optical image recognition part is positioned at an optimal position above said setting table.
Preferably, said optical image recognition part comprises: a laser beam source for projecting the scan beam; and an optical sensing element for receiving the light reflected from said IC.
The image recognized by said optical image recognition part is implemented by an image processor.
According to the present invention, a method for inspecting leads of an IC placed on a setting table is provided, which comprises the steps of: preparing an optical image recognition part disposed above said setting table, said optical image recognition part being capable of moving with respective to said setting table, said optical image recognition part for projecting a scan beam onto said setting table and receiving a light reflected therefrom; scanning said setting table with said optical image recognition part while moving said optical image recognition part with respect to said setting table; determining an optimal position of said optical image recognition part on the basis of an output signal of said optical image recognition part during said step of scanning, said optimal position at which an optimal image of said IC can be achieved; and positioning said optical image recognition part at said optimal position.
It is preferable that said setting table is stepwise scanned.
Further, the step of determining said optimal position comprises the steps of: setting a temporary position of said optical image recognition part, said temporary position at which a value of said output signal is greater than a predetermined reference value; moving said optical image recognition pait from said temporary position in a direction which increases said value of said output signal; and detecting a position at which said value of said output signal is maximized.
Furthermore, said step of setting said temporary position comprises the steps of: positioning said optical image recognition part at a predetermined position; comparing said value of said output signal at said predetermined position with said reference value; regarding said predetermined position as said temporary position if said value of said output signal is greater than said reference value; moving said optical image recognition part if said value of said output signal is smaller than said reference value; and performing said step of comparing again after said step of moving.
Preferably, said optical image recognition
Boudreau Leo
Burns Doane Swecker & Mathis L.L.P.
Samsung Electronics Co,. Ltd.
Werner Brian P.
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