Optics: measuring and testing – Position or displacement
Reexamination Certificate
1999-10-12
2002-12-17
Stafira, Michael P. (Department: 2877)
Optics: measuring and testing
Position or displacement
C356S237100
Reexamination Certificate
active
06496272
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an illuminator, which radiates light onto a to-be-mounted component conveyed by the head of a component mounting apparatus, in order to detect the posture and position of the electronic component, and also relates to the component mounting apparatus with the illuminator.
2. Description of the Related Art
A known component mounting apparatus (mounter) has a head which is movable in X-, Y- and Z-directions and which holds an electronic component by suction and conveys the electronic component to a predetermined mounting position. In this type of mounter, however, deviations can occur in the position and posture of the electronic component. In consideration of this, the electronic component held by the head is photographed with a camera in order to recognize the position and posture of the electronic component, and the operation of the head is controlled and corrected to mount the electronic component in its predetermined position.
Conventional mounters adopt various ideas for enabling the camera to photograph the electronic component with improved precision. Some mounters employ an illuminator to illuminate the electronic component held by the head with light.
A conventional illuminator is square in cross section and includes a case
520
having inner surfaces on which light sources
540
and light reflectors
580
are arranged as illustrated in
FIGS. 14A and 14B
, for example. A to-be-mounted electronic component
1
located above the illuminator is illuminated with light emitted from the light sources
540
.
According to the above illuminator, however, when illuminating an electronic component having burnished leads
1
b
with light as illustrated in
FIG. 15
, the light radiated onto the leads
1
b
is reflected in a direction different from that of a camera
650
, under which condition the leads
1
b
of the electronic component do not uniformly glisten in white, entailing the possibility that any curved portions of the leads
1
b
may be photographed partially black.
SUMMARY OF THE INVENTION
The present invention has been made in consideration of the above-described circumstances, and an object thereof is to provide an illuminator which can appropriately illuminate a to-be-mounted component with light, and a component mounting apparatus having such illuminators.
Another object of the present invention is to provide an illuminator which can improve the accuracy of recognition of the position and posture of a to-be-mounted component, and a component mounting apparatus having such illuminators.
According to the first aspect of the present invention, there is provided an illuminator for illuminating a to-be-mounted component with light, comprising:
light sources; and
a reflector including a cylindrical member with a mirror-like inner surface by which light emitted from the light sources is reflected and radiated onto the to-be-mounted component.
According to the illuminator of the present invention, the light incident from the light source is reflected by the inner surface of the cylindrical member and radiated onto the to-be-mounted component with an intensity same as that of the incident light. Therefore, an image of the to-be-mounted component and background thereof with a high contrast can be obtained. Thus, the posture and position of the to-be-mounted components can be recognized with a high precious. Further, images of the parts of the to-be-mounted component, for example, images of electrodes are clear and precise. Thus, the presence or absence of any damaged/broken part of the electrode, for example, can be easily detected.
It is desirable that the inner surface of the cylindrical member may reflect the light emitted from the light sources and radiate light having a directivity, onto the to-be-mounted component.
If directivity of the light is too high, the to-be-mounted component can not be illuminated preferably. On the other hand, directivity of the light is too low, the contrast of the image is low. According to the this structure, the light is reflected by the miller-like inner surface of the cylindrical member and radiated on the to-be-mounted components from many directions with an intensity same as that of the incident light. Therefore, light having directivity are irradiated on the to-be-mounted components without unevenness, resulting in an image of the components and background with high contrast. Thus, the posture and position of the to-be-mounted components can be recognized with a high precious. To obtain the light having directivity, ratio of diameter to length (diameter/length) of the cylindrical member is, for example, 3/12 to 10/12, more specifically, 5/12 to 10/12, and further 7/12 to 9/12.
It is desirable that the cylindrical member leads, to the to-be-mounted component, the light emitted from the light sources, while reflecting the light by the inner surface; and the light sources are arranged inside the cylindrical member and emit light in an inner space defined by the cylindrical member.
According to this structure, the light having directivity is irradiated onto the to-be-mounted components without unevenness. Therefore, an image of the components and background with a high contrast can be obtained.
It is desirable that the cylindrical member has a first end and a second end; and
the light sources include
first light sources forming a first light source group and arranged at the first end of the cylindrical member which is closer to the to-be-mounted component than the second end of the cylindrical member,
second light sources forming a second light source group and arranged at the second end of the cylindrical member, and
third light sources forming a third light source group and arranged between the first and second ends of the cylindrical member.
According to this structure, the light rays radiated at different angles from the first to third light sources are radiated onto the to-be-mounted components without unevenness with directivity by reflected on the inner surface of the cylindrical member. Therefore, an image of the to-be-mounted components and background can be obtained. Thus, the posture and position of the to-be-mounted components can be recognized with a high precious.
The cylindrical member is circular in cross section, for example. In this case, for example, the first, second and third light sources are arranged in a circumferential direction of the cylindrical member.
According to this structure, the light rays emitted from the first, second and third light sources are radiated onto the to-be-mounted components at various angles throughout the whole circumference thereof. Therefore, the light is irradiated onto the to-be-mounted components without unevenness, and the form and position of the to-be-mounted components can be recognized with a high precious.
The cylindrical member covers, for example, parts of the first light sources which face the second end of the cylindrical member, in order to prevent light from being emitted toward the second end of the cylindrical member from the first light sources.
According to this structure, the light rays are prevented from being radiated toward the second end from the first light sources and from being unnecessarily radiated onto the components. Thus, in a case where the to-be-mounted components are, for example, BGA type semiconductor chips, the presence or absence of damaged/broken part in their ball-shaped surface can be easily detected, because the ball-shaped surfaces are glistening annularly (in a doughnut shape).
The cylindrical member has a bottom which covers at least a part of an opening at the second end of the cylindrical member, and the second light sources are arranged on the bottom.
A diffusion member in a form of a flat plate, which diffuses light emitted from the second light sources, is arranged almost perpendicular to an axis of the second cylindrical member and between the first light source group comprising the second light sources and the third light source group comprising the
Frishauf Holtz Goodman & Chick P.C.
Stafira Michael P.
Yamagata Casio Co., Ltd.
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