JP2002237967A - Light-emitting diode illumination light source - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact light-emitting diode illumination light source that can emit luminous quantity required for inspection, even almost in parallel with an image pickup optical axis even in a narrow inspection range, can be manufactured at a low cost and mounted on an existing imaging camera. SOLUTION: The light-emitting diode illumination light source is provided with a multi-plane reflecting mirror 120 having a plurality of slopes configuring the circumferential wall of a poly truncated pyramid shape in the middle of which an imaging hole 123 is formed for reflecting faces 122 and with a plurality of 1st light-emitting diode groups 130, which are respectively and radially laid out toward the reflecting faces 122. The light-emitting diode illumination light source is configured, such that the light emitted by the 1st light-emitting diode groups 130 is reflected in the respective reflecting faces 122 and is irradiated onto an object 180 to be inspected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used to illuminate a photographing location when inspecting the quality of an industrial product or the like on a production line by using an image of a CCD camera or the like.
The present invention relates to an illumination light source using a light emitting diode.

[0002]

2. Description of the Related Art As a method of inspecting the quality of industrial products such as printed circuit boards and semiconductors, for example, defective soldering, defects, adhesion of foreign substances, etc., on a production line, a method using imaging by a CCD camera or the like has been widely used. ing. In this method, a specific part of a component is imaged, and the presence or absence of an abnormality is inspected by comparing the result with an imaging result of a normal component. In such an inspection method, it is necessary to uniformly and brightly illuminate the imaging site of the CCD camera with an illumination light source.
Here, in the above inspection method, generally, a halogen lamp, a light emitting diode, or the like is preferably used, and a method of annularly mounting around an imaging camera is generally known.

However, in the above method, light is obliquely emitted from the annular light source to the object to be inspected, and as a result, when the object to be inspected has a three-dimensional shape, a shadow is generated and accurate. In some cases, stable image processing cannot be performed.
Also, if there is a transparent coating layer on the surface,
In light obliquely from occurring even not be able to determine the underlying defect to scattering irradiation light in the coating layer surface. Therefore, in such an inspection target, it is necessary to irradiate the inspection object with the inspection light vertically.

As a method for solving the above problem, a half mirror is arranged on a straight line connecting the imaging camera and the object to be inspected, and light is irradiated from the side toward the half mirror to emit illumination light on the optical axis. A technique of falling incident light, so-called coaxial falling illumination, is known and widely used.

Japanese Patent Application Laid-Open No. 9-311928 discloses an image pickup device for picking up an image of an object to be inspected and irradiating the object to be inspected with light from directly above the object to be inspected. A built-in coaxial epi-illumination camera comprising: a light-emitting element;
A coaxial epi-illumination built-in camera, which is a chip and the light emitting element is a light emitting diode, is disclosed.

Further, Japanese Patent Application Laid-Open No. 11-173822 discloses an apparatus in which an image pickup device picks up an appearance and a display of a surface of an electronic component while irradiating the electronic component with illumination light from a lighting device. light is irradiated substantially perpendicularly to the plane, the second irradiating a first illuminator which is arranged in a ring shape so as to surround the optical axis of the imaging device, the light obliquely to the plane of the electronic component And an image pickup device for imaging the plane with an optical axis substantially perpendicular to the plane of the electronic component, and wherein the illuminator is a light-emitting diode.

[0007]

However, in the above-described method using coaxial incident light, although the problem of the optical axis is solved and complete coaxial incident light is obtained, irradiation of the inspection object by passing through a half mirror is performed. Since the amount of light and the amount of light reaching the image sensor are significantly reduced, there is a problem that the amount of light is insufficient, particularly when a small portion of the object to be inspected is to be inspected. Further, since the half mirror is arranged coaxially, there are problems that the structure is complicated and cannot be made compact, and that the cost increases.

Further, in the JP-A 9-311928 discloses a technique, since the built-in coaxial incident illumination to the camera apparatus becomes compact, although it is possible to irradiate substantially vertically, maintenance, etc. is complicated ,Also,
Since it is built-in, there is a problem that it cannot be attached to an existing CCD camera and is not versatile.

Further, in the technique disclosed in Japanese Patent Application Laid-Open No. H11-173822, the first illuminator for irradiating light substantially perpendicular to the plane of the electronic component is directly disposed around the image pickup device. When the number of light emitting diodes increases, the light emitting diodes are arranged in an annular shape at an outer peripheral position distant from the optical axis. For this reason, in the case of a semiconductor or the like having a very small inspection area, there is a problem that the light is not vertically incident on the inspection object.

Therefore, an object of the present invention is to make it possible to project a sufficient amount of light sufficient for illumination required for inspection almost perpendicularly onto an object to be inspected, to manufacture it compactly at a relatively low cost, and to use an existing light source. An object of the present invention is to provide a light emitting diode illumination light source that can be attached to an imaging camera.

[0011]

In order to achieve the above object, a light-emitting diode illumination light source according to the present invention is provided with an imaging hole at the center of a polygonal truncated pyramid, and a plurality of peripheral walls forming the peripheral wall of the polygonal truncated pyramid. A plurality of first light emitting diode groups radially arranged toward the respective reflecting surfaces of the polygon mirror; and a plurality of first light emitting diode groups arranged radially toward the respective reflecting surfaces of the polygon mirror.
The light emitted from the light emitting diode group is reflected on each reflecting surface of the polygon mirror and irradiated on the inspection object.

According to the present invention, the light emitted from the first light emitting diode group is turned back by the polygon mirror and radiated to the inspection object immediately below the reflector. in this case,
By using the reflecting mirror, since it is possible to reflect light at a position very close to the imaging optical axis, it is possible to fall almost coaxially with the imaging optical axis, even when the inspection range is narrow. Applicable. In addition, since a plurality of light emitting diodes arranged radially can be simultaneously projected using the polygon mirror, a sufficient amount of light can be obtained. Furthermore, since the hole for imaging was provided in the center part,
It can be easily installed on existing CCD cameras, etc., and is excellent in versatility.

According to a further preferred aspect of the present invention, a second light emitting diode group is further annularly arranged around the first light emitting diode group, and the second light emitting diode group arranged in the annular shape. The light emitted by the device is configured to be directly radiated toward the inspection object. This allows
In addition to the substantially coaxial incident light by the first light emitting diode group,
Irradiation from an oblique direction by the second light emitting diode group is also possible, and the inspection accuracy can be further improved by using the first and second light emitting diode groups simultaneously or by switching.

[0014]

1 to 4 show an embodiment of a light source for illuminating a light emitting diode according to the present invention, and the present invention will be described in more detail. FIG. 1 is a side view of a light emitting diode illumination light source according to the present invention, FIG. 2 is a plan view of the illumination light source,
FIG. 3 is a perspective view of the illumination light source, and FIG. 4 is an exploded perspective view of the illumination light source.

As shown in FIGS. 1 to 4, a light emitting diode illumination light source 100 according to this embodiment includes a substrate 110, a polygon mirror 120, a first light emitting diode group 130, and a support 14.
0, a holding plate 150, a second light emitting diode group 160, and a housing 170.

Hereinafter, each component will be described. The substrate 110 is provided with a hole 111 through which the polygon mirror 120 is penetrated.
The has, furthermore the circuit component 112, connector 113 of power resistors and the like are arranged. The hole 111
, A first light emitting diode group 130 is supported, and around the first light emitting diode group 130, a second light emitting diode group 160 is supported concentrically.

Here, as the light emitting diodes used for the first light emitting diode group 130 and the second light emitting diode group 160, those conventionally used can be used.
There is no particular limitation. Further, by selecting a light emitting diode of a desired color, it is possible to output illumination light of a color according to the purpose. In this case, RGB
If light emitting diodes of three colors are alternately mixed and arranged so that only a desired light emitting diode emits light according to a target color, it is possible to output various colors with one illumination light source.

The polygon mirror 120 includes a flange portion 121 for attachment to the substrate 110 and a hole 111 of the substrate 110.
And a truncated polygonal pyramid-shaped main body that is inserted from the back surface of the substrate 110 and protrudes above the substrate. Further, using a hole 124 of the flange portion 121, a set screw 15 described later is used.
1 fixed to the substrate 110.

In the present invention, the polygon mirror 120 is
An imaging hole 123 is provided at the center of the truncated polygonal pyramid, and a plurality of slopes forming a peripheral wall of the truncated polygonal pyramid form a reflection surface 122. In the present embodiment shown in FIGS. 1 to 4, a nine-surface reflecting mirror having nine reflecting surfaces is provided, and has a truncated pyramid shape. The number of the reflection surfaces 122 of the truncated polygonal pyramid is not particularly limited, and can be appropriately selected such as a truncated pyramid, a truncated pyramid, or the like according to a required light amount. In addition, the size of the polygon mirror 120 is not particularly limited, but it is preferable that the polygon mirror 120 be smaller in order to project the light more coaxially with the imaging optical axis.

As the reflection surface 122, a light-emitting material such as a material obtained by polishing a metal such as aluminum or brass, or a material obtained by molding a glass or a synthetic resin and subjecting the surface to metal deposition of aluminum, gold, silver or the like is used. Materials that suitably reflect diode light can be used as appropriate. Further, the inclination angle of the reflection surface 122 can be appropriately changed depending on the size of the inspection object 180 and the irradiation distance.

The size and shape of the imaging hole 123 are not particularly limited, and can be appropriately selected according to the size and shape of the element portion of the imaging camera 190, and are not necessarily circular.
Furthermore, the reflection surface 122 does not necessarily need to be a plane,
It is also possible to prevent the reflected light of the light emitting diode from being spread by forming a concave curved surface or the like.

The support table 140 has a hole 142 through which the polygon mirror 120 passes. The support table 140 is arranged on the circumference of the substrate 110 between the polygon mirror 120 and the first light emitting diode group 130. ing. Here, on the support 140,
Concave portions 141 are formed corresponding to the respective light emitting diodes of the first light emitting diode group 130. Each of the light emitting diodes mounted on the substrate 110 has its legs bent and fitted into the concave portions 141 to be horizontal. , And are arranged radially so that the light irradiation direction is directed to the corresponding reflection surface 122 of the polygon mirror 120.

Further, from above, the polygon mirror 12
A holding plate 150 having a hole 152 desired by the first light emitting diode group 130 is formed by screwing a set screw 151 through the holding plate 150, the support base 140, and the substrate 110 to the flange 121 of the polygon mirror. Further, the polygon mirror 120 is fixed to the substrate 110.

On the other hand, is also supported on the substrate 110, the second light emitting diode group 160 disposed concentrically around the first light emitting diode group 130, the housing 17
0 is inserted into the hole 171 so as to be supported at a predetermined irradiation angle. That is, the housing 170,
A plurality of holes 171 corresponding to each light emitting diode of the second light emitting diode group 160 are provided in a ring shape, and a hole 142 desired by the polygon mirror 120 is provided at the center. Then, the housing 170 is fitted from above the second light emitting diode group 160, and a set screw (not shown) is screwed to the substrate 110 through the hole 172 of the flange portion.
It is fixed to 10.

Here, the hole 171 of the housing 170 is
The light emitting diodes of the second light emitting diode group 160 are inserted into the holes 171 to form a predetermined irradiation angle at a predetermined angle corresponding to the irradiation angle to the inspection object 180. Is to be retained.

Inspection object 1 of second light emitting diode group 160
The irradiation angle to the object 80 can be appropriately set depending on the irradiation range, the distance, and the like to the inspection object 180.
It can be changed by changing the angle of the zero hole 171. In addition, the second light emitting diode groups arranged in a ring need not necessarily be arranged in one row, but may be arranged in a double or triple ring.

As shown in FIG. 1, the imaging camera 190 is located at an upper portion of the polygon mirror 120 where the imaging hole 123 is desired.
The optical axis of the imaging element (not shown) is arranged to be perpendicular to the inspection object 180. C is an imaging device
A CD or the like can be suitably used.

Here, the distance between the light emitting diode illumination light source 100 of the present invention and the inspection object 180 can be selected according to the size of the inspection object 180, the irradiation range, and the like, and is not particularly limited. In addition, the imaging camera 180 may be disposed apart from the light emitting diode illumination light source 100 as shown in FIG. 1, or may be inserted in the imaging hole 123 of the polygon mirror 120.

Next, the light emitting diode illumination light source 100
The operation of will be described. First, a predetermined voltage is applied from the power supply circuit (not shown) to the first light emitting diode group 130 and the second light emitting diode group 160 via the connector 113 on the substrate 110 and the circuit pattern wiring (not shown) having the electronic circuit component 112. The LED group is supplied to emit light.

As shown in phantom in FIG. 1, the light emitted toward the reflecting surface 122 of the polygon reflecting mirror 120 from the first light emitting diode group 130, each corresponding reflecting surface 12
The light is reflected by the object 2, irradiates the inspection object 180, and passes through the imaging hole 123 of the polygon mirror 120, and the imaging camera 1
An inspection is performed by 90.

At this time, since the polygon mirror 120 has the reflection surface 122 adjacent to the periphery of the imaging hole 123, the light of the light emitting diode is almost parallel to the imaging optical axis. Thus, an illumination effect close to the coaxial incident light can be obtained. Further, even when the number of the first light emitting diode groups 130 is increased, each light emitting diode can be radially arranged, so that there is little space limitation. There is no need to make the reflector large. Accordingly, the angle of the incident light can be increased by increasing the number of light emitting diodes while maintaining the angle of incidence substantially parallel to the imaging optical axis. ,In particular,
Even when the object to be inspected is very small, or when it is necessary to inspect a minute part in an enlarged manner, it is possible to irradiate with a sufficient amount of light and close to coaxial incident light.

Further, in the light emitting diode illumination light source of the present invention, the imaging camera 190 includes the polygon mirror 120.
Can be inspected through the image pickup hole 123, and can be attached to an existing CCD camera or the like, and can provide an illumination effect close to coaxial incident light, so that it is excellent in versatility. In addition, it can be produced at low cost, and has excellent maintainability as compared with the built-in type.

On the other hand, the light emitted from the second light emitting diode group 160 is directed obliquely toward the inspection object 180. Thus, the only the first light emitting diode group 130 can allow the inspection of the uneven shape of the insufficient vertical inspection accuracy, further first light emitting diode group 13
With 0, insufficient light quantity and uneven brightness can be compensated.

In the present invention, the second light emitting diode group 160 may be used together with the first light emitting diode group 130, and the first light emitting diode group 13 may be used.
It can be used separately instead of switching to 0, and can be appropriately selected. Thus, in accordance with the shape and nature of the inspection object 180, a necessary portion can be accurately inspected possible with common illumination light source.

[0035]

As described above, according to the present invention,
A sufficient amount of light for the illumination required for inspection can be projected almost vertically even when the object to be inspected is small or in a narrow inspection area that needs to be enlarged by image processing. can be produced, besides it is possible to provide a light emitting diode illumination source is attachable to an existing imaging cameras.

[Brief description of the drawings]

FIG. 1 is a side view of a light emitting diode illumination light source according to the present invention.

FIG. 2 is a plan view of the illumination light source.

FIG. 3 is a perspective view of the illumination light source.

FIG. 4 is an exploded perspective view of the illumination light source.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 light emitting diode illumination light source 110 substrate 120 polyhedral mirror 122 reflecting surface 123 imaging hole 130 first light emitting diode group 140 support base 150 holding plate 160 second light emitting diode group 170 housing 180 inspected object 190 imaging camera

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H042 DA02 DA04 DA05 DA10 DA11 DA12 DC02 DD01 DE04 2H052 AC04 AC17 AC27 AC30 AC33 5C022 AA01 AB15 AC42 AC78

Claims (2)

[Claims] A polygonal frustum provided with an imaging hole at the center of the polygonal frustum, and a plurality of slopes constituting a peripheral wall of the polygonal frustum serving as reflection surfaces; and a reflection surface of each of the polygonal reflection mirrors. A plurality of first light-emitting diode groups radially arranged toward each other, and light emitted from the plurality of first light-emitting diode groups is reflected on each reflecting surface of the polygon mirror to irradiate the inspection object. A light emitting diode illumination light source characterized in that it is configured to 2. A second light emitting diode group is further annularly arranged around the plurality of first light emitting diode groups, and light emitted from the annularly arranged second light emitting diode group is directly received. the light emitting diode illumination source according to claim 1, wherein is configured to be irradiated toward the inspected object.