JPH0315708A - Illuminating device for parts mounted substrate - Google Patents

Abstract

PURPOSE:To uniformly illuminate a parts mounted substrate by providing a reflection plate and a diffusion plate having shapes corresponding to the respective two-divided spherical shells whose radii are different and installing a light source in a space part lying between the reflection plate and the diffusion plate. CONSTITUTION:A light beam directly advancing to the diffusion plate 12 and a light beam advancing to an auxiliary reflecting plate 112 are radiated from a light source 14. Considering only the light beam advancing to the diffusion plate 12, many direct light beams are concentrated on the position of the diffusion plate 12 which is near the light source 14 and the direct light beams are sparse at a position which is distant from the light source, so that it becomes bright at the position near the light source 14 and it becomes dark at the position distant from it. Considering the light beam which is reflected by the auxiliary plate 112 to advance to the diffusion plate 12, the reflected light beams are concentrated on the position distant from the light source 14, so that it becomes bright at the position distant from the light source 14 and it becomes dark at the position near it. The parts mounted substrate 30 on an X-Y table is illuminated with the light beams 145 from the diffusion plate 12. Then, the substrate 30 is photographed by an image pickup device 21 inserted in an image pickup observation hole 13.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a lighting device for illuminating a board on which electronic components, etc. are mounted, and more particularly relates to a component mounting board lighting device for providing shadowless illumination. .

<Conventional technology> When incorporating chip components such as ICs, capacitors, or transistors into electronic devices, the method used is to attach these chip components to a printed circuit board with printed wiring. In order for an electronic device with a built-in chip to operate properly, each chip component must be of good quality and must be installed correctly. Therefore, the installation condition of the chip components must be inspected during assembly. has been done.

This inspection is carried out based on the image obtained by imaging the printed circuit board on which the chip components are mounted, so as shown in FIG.
A plurality of COD cameras 93 are arranged diagonally above a component mounting board 92, which is a printed circuit board on which chip components 95 are mounted, and a COD camera 93 is mounted directly above the component mounting board 92.
The wearing state is determined by taking an image and guiding the obtained image signal to the image processing circuit 94. In this determination, as shown in FIG. 7a, the land portion 921 of the component mounting board 92 is copper colored and the electrode portion 951 of the chip component 95 is silver colored. After extraction, the edge portion 921a is detected as shown in FIG. 7b. A determination method is adopted in which if the position of the detected edge portion 921a is within a permissible range, the mounting has been performed correctly, and if it exceeds the permissible range, it is determined that the mounting is incorrect. <Problems to be Solved by the Invention> In the above determination, since the color of the land portion 921 (W4 color) and the color of the main body of the component mounting board 92 (green due to solder resist applied) are different, the land portion is In order to facilitate the detection of 921, a color camera is used as the CCD camera 93, and color processing is also performed in the image processing circuit 94. Therefore, differences in brightness greatly affect color judgment, and slight illumination There was a problem that errors in judgment occurred due to spots and halation.

Further, when a shadow is created by the chip component, a dark portion 922 is created in the land portion 921, as shown in FIG. 7C. Therefore, when image processing is performed based on the signal obtained by capturing this image and edge detection is performed, the land portion 9
Since the dark part 922 of 21 is not detected as a land part, it is detected as an edge 92lb indicating that a part is missing, as shown in FIG. 7d, and it is incorrectly determined that the part is not installed correctly. A problem had arisen.

The present invention was conceived to solve the above-mentioned problems, and its purpose is to provide a component mounting board illumination device that can uniformly illuminate a component mounting board.

<Means for Solving the Problems> In order to solve the above problems, the component mounting board lighting device of the present invention divides two spherical shells having the same center and different radii, and When the spherical shell with the larger radius is used as the first spherical shell and the other spherical shell is used as the second spherical shell, it is formed in a shape similar to the l-th spherical shell, and its inner surface reflects light. a diffuser plate formed in a shape approximating a second spherical shell to diffuse transmitted light; and a plurality of light emitting units provided in a space sandwiched between the diffuser plate and the reflector plate. and an imaging peephole that passes through both the reflector and the diffuser plate, the reflector and the enlarged PIIFi. The positional relationship between the first spherical shell and the second spherical shell corresponds to the positional relationship between the first spherical shell and the second spherical shell. <Operation> Light emitted from multiple light sources is divided into light that goes directly to the diffuser plate and light that goes to the reflector plate.

Therefore, if we consider only the light that goes directly to the diffuser, the diffuser will be brighter near the light source and will become darker as it moves away from the light source. On the other hand, the light heading towards the reflector is reflected by the reflector and then towards the diffuser, so this reflected light is focused on a position far from the light source on the diffuser, and the light is reflected by the reflector. Since the light that is reflected and goes directly to the diffuser plate is complementary to the light that goes directly to the diffuser plate, the diffuser plate becomes a uniform surface light source. Furthermore, since the shape of the diffuser plate is similar to that of a spherical shell divided into two halves, the diffuser plate provides light that illuminates from all angles. The component mounting board illuminated by this light is then imaged by the imaging device through the imaging peephole.

Embodiments> Fig. 1 is an external perspective view of an embodiment of the present invention looking down from above, Fig. 2 is an external perspective view of an embodiment of the invention looking up from below, and Fig. 3 is an external perspective view of an embodiment of the present invention looking down from below. FIG. 2 is a sectional view showing an embodiment.

In the figure, the inner surface 114 of the reflector main body 111, which is made by shaping plastic or the like into a bisected spherical shell shape, has a multi-stage ridge 1l22 and a trough 1123 (see Fig. 3). On the right side of the drawing, a peak 1122 and a valley l12 are
3), a reflective auxiliary plate 112 running in a ring shape parallel to the opening surface 113 (the thickness is omitted) runs along the inner surface of the reflective plate main body 111. This reflective auxiliary plate 112
White fluorescent paint is applied to the inner surface 1l21 to increase reflectance. The opening side end 1 of the diffusion lIil2 was created by processing a plastic plate or the like with fine irregularities on both sides into a bisected spherical shell shape.
21 and the opening side end 1111 of the reflector main body 111,
Each of the lower connecting plate l5, which is a donut-shaped flat plate, is fixed to the outer peripheral edge and the inner peripheral edge with an adhesive or the like.

In addition, insertion holes l112 and 122 with the same radius are formed at the top of each of the reflection plate main body 111 and the diffusion plate 12, and the outer diameters of these insertion holes l112 and 122 are the same as those of the insertion holes l112 and 122, respectively. A plastic cylinder 131 formed to have a radius equal to the radius of 122 is inserted and fixed to the reflector body 111 and the diffuser plate 12 with adhesive. The inside of the plastic cylinder 131 serves as an imaging peephole 13 for photographing the illuminated component mounting board.

In the space 16 formed by the auxiliary reflection plate 112 and the diffuser plate 12, three ring-shaped fluorescent tubes 14 with different radii are used as light sources, and the ring portions are connected to the opening surface 113.
parallel to and formed on the auxiliary reflection plate 112,
It is fixed at positions corresponding to the three highest peaks 1125 by supports (not shown).

In the above structure, the reflector 1l is the reflector main body 11.
1 and a reflective auxiliary plate 112.

FIG. 4 is a block diagram showing the electrical configuration of an inspection device using an embodiment of the present invention, and FIG. 5 is a component mounting board illumination device (hereinafter simply referred to as illumination device) according to the present invention.
FIG. 3 is a cross-sectional view showing the relationship between a component mounting board, a component mounting board, and an imaging device.

The component mounting board 30 on which the chip component 301 is mounted is
The lighting system 10 is placed on an X-Y table 35 that moves in the Y direction, and a lighting device 10 is attached to the center of the upper part of the X-Y table 35 by a support (not shown). An imaging device rIl21, whose lens portion 211 is inserted into the imaging peephole l3, is attached to the. The output of the imaging device 2l is led to an image processing circuit 32 via an A/D converter 31, and the output of this image processing circuit 32 is given to a control circuit 33. The output of the control circuit 33 is output from the X-Y table 35.
, which controls the rotation of the X-axis motor 36 that moves the
-Y table 35 is sent to drive unit 34.

The operation of one embodiment of the present invention having the above configuration will be explained below. The light source 14 emits light 141 directly toward the diffuser plate l2 and light 142 toward the auxiliary reflection plate 112.
Therefore, when considering only the light 141 that goes directly to the diffuser plate work 2, a lot of direct light 141 is concentrated on the W123 near the light source 14 of the diffuser plate 12, and the direct light 141 is concentrated on the W123 at a position 124 far from the light source 14. Since the light sources 141 are sparse, a position 123 close to the light source 14 is bright, and a position 124 distant from the light source 14 is dark.

On the other hand, it is reflected by the auxiliary reflection plate 112 and the diffuser plate 12
Considering the light 144 directed toward the light source 14, this reflected light 144 will be concentrated at a position 124 away from the light source 14, so the position 124 away from the light 'rAl4 will be bright, and the position 123 closer to it will be dark.

In other words, the diffuser plate 12 receives direct light l41 from the light source l4.
Since the light and the reflected light 144 from the auxiliary reflection plate 112 are irradiated so as to complement each other, the diffuser plate 12 becomes a uniform surface light source. The component mounting board 30 on the XY table 35 is illuminated by the light 145 from the diffuser plate l2, which serves as a uniform surface light source. Then, the component mounting board 30 is imaged by the imaging device 2l whose lens portion 211 is inserted into the imaging peep hole l3. A signal representing an image captured by this imaging device 2l is guided to an image processing circuit 32 via an A/D converter 31. Then, the image processing circuit 32 detects the edge of the land portion, thereby determining the mounting state of the chip component 301.

Since this determination is performed for each region of the component mounting board 30, each time the determination of one region is completed, an output indicating completion is sent to the control circuit 33, and the X-Y table 30 is
The X-Y table 35 is rotated by rotating the motors 36 and 37 for the X and Y axes via the drive unit 34.
move. Then, the next area of the component mounting board 30 is imaged, and the chip component 301 is imaged based on the imaged result.
determines the wearing status of the

It should be noted that the present invention is not limited to the above-mentioned embodiments. Regarding the ring-shaped fluorescent tube 14 that is the light source 14, the case where three fluorescent tubes are employed as the light source 14 has been described, but other numbers may be used, for example, four. It is possible to have a configuration using ring-shaped fluorescent tubes such as.

Furthermore, although the imaging peep hole 13 has been described in the case where it is provided at the top of the reflecting plate l1, it can be provided at any other position other than the top as a position corresponding to imaging.

Effects of the Invention> The component mounting board lighting device according to the present invention includes a reflecting plate and a diffusing plate each having a shape corresponding to a spherical shell divided into two halves with different radii, and a lighting device sandwiched between the reflecting plate and the diffusing plate. Since the light source is provided in a space with a light source, the diffuser plate is uniformly illuminated by direct light from the light source and reflected light from the reflector, and the diffuser plate becomes a surface light source. This makes it possible to uniformly illuminate the board on which components are mounted.

[Brief explanation of the drawing]

Fig. 1 is an external perspective view of an embodiment of the present invention looking down from above; Fig. 2 is an external perspective view of an embodiment of the invention looking up from below; Fig. 3 is an embodiment of the present invention. 4 is a block diagram showing the electrical structure of an inspection device using an embodiment of the present invention. FIG. 5 is a cross-sectional view showing a component mounting board lighting device and a component mounting board according to the present invention , and a cross-sectional view showing the relationship with the imaging device; FIG. 6 is an explanatory diagram showing an outline of a conventionally used illumination device; FIGS. 7a to 7d show the land portion of the component mounting board FIG. 3 is an explanatory diagram showing how detection is performed. 10...Component mounting board illumination device 1l...Reflection plate 12...Diffusion plate 13...Imaging peep hole 14...Light source 30...Component mounting board.

Claims (1)

[Claims] (1) Two spherical shells with the same center and different radii are divided into two, the one with the larger radius is used as the first spherical shell, and the other spherical shell is used as the first spherical shell. When forming a second spherical shell, it is formed in a shape similar to the first spherical shell, and has a reflecting plate whose inner surface reflects light; A diffuser plate that performs diffusion, a plurality of light emitting parts provided in a space between the diffuser plate and the reflector plate, and an imaging peephole that passes through both the reflector plate and the diffuser plate. A lighting device for a component mounting board, characterized in that the positional relationship between the reflection plate and the diffuser plate corresponds to the positional relationship between the first spherical shell and the second spherical shell.