JPH04103145A - Parts inspection equipment - Google Patents

Abstract

PURPOSE:To make it possible to realize a high-accuracy and high-efficiency inspection of a component to be inspected without needing an accurate positioning and without needing labor by a method wherein inspection light is projected through the incident surface on the outer periphery of a transparent plate and while being repeated a total reflection in the support plate, the light is made to travel and the component to be inspected is observed via the support plate. CONSTITUTION:A component 1 which is an object to be inspected is placed on a support surface 15 of a transparent support plate 11 covered with a liquid film 24 and thereafter, a light source 12 and an imaging device 13 are actuated and an inspection of leads 2 is executed. Inspection light C emitted from the light source 12 is made to fall on the plate 11 and thereafter, while being totally reflected in the plate 11, the light C is made to proceed. When the light C strikes on parts, which come into contact to the surface 15 or the film 24, of the leads 2, the light C is irregularly reflected at the contact parts and the state of total reflection is disarranged. As a result, irregularly reflected light (d) is made to pass through the lower surface of the plate 11 and is made to travel in the direction of the device 13. The light (d) is observed by the device 13 and the complete images of the leads (2) are formed.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a component inspection device used to inspect an electronic component such as a QFP having a plurality of leads.
In particular, the present invention relates to a component inspection device suitable for detecting deformation of the leads and determining the quality of the component.

<Prior art> For example, when an electronic component (hereinafter simply referred to as a "component") such as a QFP is surface mounted on a printed circuit board, as shown in FIG. If so, the leads 2 will rise above the surface of the printed circuit board 3, and proper soldering will not be performed, resulting in poor soldering. Therefore, before mounting the electronic components, it is necessary to check whether all the glues 2 are suitable or not to determine whether the components are good or bad.

Conventionally, as a component inspection device of this kind, one having the configuration shown in FIG. 8 has been proposed.

In the figure, reference numeral 1 denotes a component to be inspected, and a large number of glue points 2 protrude from all sides. After the component 1 is positioned and placed at a suitable location on the inspection table, the component inspection device 4 inspects whether the lead 2 is deformed or not.

The illustrated component inspection device 4 includes a pair of laser light sources 5A, 5.
After guiding the inspection lights a and b from B along two sides of the component 1, the inspection lights a and b are reflected by reflection mirrors 6A and 6B, respectively, and guided along the other two sides, and the light receivers 7A and Light is being received at 7B.

When making the optical path of each inspection light a and b correspond to the tip position of the lead 2, if all the leads 2 are in a proper state, the inspection light a
, b pass directly above each lead 2 and are received by the light receivers 7A and 7B. However, if any of the leads 2 are floating above the lead 2, the optical path is blocked by that lead 2, and the inspection light is transmitted to the light receiver. The light does not reach the target and is not received.

In this way, both the light receivers 7A and 7B receive the inspection light a.

When light b is received, it is determined that the lead 2 of the component 1 is in a proper state, and if either of the light receivers 7A and 7B does not receive the inspection light a or b, it is determined that a lead defect has occurred. do.

<Problems to be solved by the invention> However, in the case of the above configuration, it is necessary to accurately position the component 1 to be inspected at the inspection position of the inspection ball, and the position adjustment is difficult (especially when the component size is small). , a slight positional shift of the component makes proper inspection difficult.Also, each time the inspection target is changed, each component of the component inspection device 4, that is, the laser light sources 5A, 5B, the reflecting mirrors 6A, 6B, and the light receivers 7A, 7B, is changed. There is a problem in that it is necessary to change the installation position of each component, and that it takes time and effort to perform inspection and preparation.

The present invention has been made in view of the above problem, and an object of the present invention is to provide a component inspection device that does not require accurate positioning of components during inspection, and does not require time and effort for inspection preparation.

Another object of the present invention is to enable a component inspection system that can absorb the error and perform proper inspection even when there are variations in the height of the leads, especially when inspecting electronic components having a plurality of leads. The point is to provide equipment.

<Means for Solving the Problems> The component inspection device of the present invention includes a transparent support plate, a light source, and an imaging device. The transparent support plate has an upper surface serving as a support surface for supporting the inspection component, a liquid film provided on the support surface, and one end surface of the outer periphery serving as an incident surface for inspection light. The light source is arranged to face the incident surface, and the projection direction of the inspection light is set so that the inspection light travels through the transparent support plate while repeating total reflection. The imaging device is disposed below the transparent support plate, and its field of view is set so that the inspection component can be observed through the transparent support plate.

<Function> When a component is placed on the support surface of the transparent support plate,
When the inspection area of the component comes into contact with the support surface, the inspection light hits the contact area and is diffusely reflected. Therefore, the diffusely reflected light is observed by the imaging device, and a complete image of the inspected area in contact can be obtained. On the other hand, when the inspection area of the component is not in contact with the support surface due to lifting etc., the inspection light passes through the transparent support plate by total reflection, so the diffused reflected light is not observed by the imaging device and the inspection area A complete picture is not available. Therefore, it is possible to determine whether the part is good or bad depending on whether an image of the inspection site can be properly obtained.

If the object to be inspected is a component with multiple leads, even if the height of the leads varies, the error will be absorbed by the liquid film, and the component can be pressed against the support surface and brought into contact. Appropriate inspections can be performed without requiring any additional operations.

<Embodiment> FIG. 1 shows a component inspection device 1 according to an embodiment of the present invention.
Indicates 0.

The illustrated component inspection device 10 is for inspecting an electronic component 1 such as a QFP in which a large number of boards 2 protrude in all directions, but this device is not limited to inspection of this type of electronic component. It can also be applied to the inspection of other types of electronic components, as well as mechanical components other than electronic components.

This component inspection device 10 has a transparent support plate 11, a light source 12, and an imaging device 13, and an image processing device 14 is electrically connected to the imaging device 13.

The transparent support plate 11 is made of a synthetic resin plate such as acrylic or a glass plate with a constant thickness and parallel upper and lower surfaces.
The upper surface serves as a support surface 15 for supporting the component 1 to be inspected, and a liquid film 24 of approximately constant thickness is provided on this support surface 15 by spraying or coating. 20 The liquid film 24 is used to absorb variations in the height of the leads 2 of the electronic component 1 to be inspected, and is therefore formed using a non-volatile liquid with low viscosity and small surface tension. According to experiments, it has been confirmed that the desired effect can be obtained when the liquid film 24 is formed using Display Cleaner (manufactured by IBM Corporation) as the liquid agent. This liquid has a surface tension of about 0.02 N/m and is a surfactant.

The ingredients include antistatic agents, fluorinated solvents, and liquefied petroleum gas.

Further, the illustrated transparent support plate 11 has a rectangular planar shape,
At least one end surface of the outer peripheral end surface is formed obliquely,
It serves as an entrance surface 16 through which the inspection light C is incident.

The light source 12 is, for example, a laser light source, and forms a slit-shaped inspection light C by passing its output light through an optical system such as a cylindrical lens. As shown in FIG. 2, this inspection light C is projected at right angles toward the incident surface 16 of the transparent support plate 11 with the width direction of the light matching the length direction of the incident surface 16. The projection direction, that is, the oblique angle θ of the incident surface 16 is set so that all of the light travels through the transparent support plate 11 by repeating total reflection.

FIG. 4 shows the principle in which all of the inspection light C travels through the transparent support plate 11 while being totally reflected.

Although the liquid film 24 is omitted in this figure, in principle, the liquid film can be considered as a part of the transparent support plate 11.

In FIG. 4(1), the inspection light C is incident on the interface 18 between the transparent support plate 11 and the outside air 17 at an angle α smaller than the field angle Di. In this case, part of the inspection light C is at the boundary surface 18.
The light is refracted at the angle β and travels into the outside air 17, and the other part is totally reflected at the boundary surface 18 and travels inside the transparent support plate 11.

In FIG. 4(2), the inspection light C is incident on the interface 18 between the transparent support plate 11 and the outside air 17 at an angle α that coincides with the critical angle. In this case, a part of the inspection light C is refracted at the boundary surface 18 and travels along the boundary surface 18 into the outside air 17 at an angle β (=90''), and the other part is totally reflected at the boundary surface 18. It will proceed inside the transparent support plate 11.

In FIG. 4(3), the inspection light C is incident on the interface 18 between the transparent support plate 11 and the outside air 17 at an angle α larger than the critical angle. In this case, all of the inspection light C is totally reflected at the boundary surface 18 and travels inside the transparent support plate 11.

Therefore, in the transparent support plate 11 having a constant plate thickness, the incident surface 16 of the transparent support plate 11 is inclined so that the inspection light C is incident on one boundary surface (for example, the bottom surface) with the outside air at an angle α larger than the critical angle. If the angle θ is set, the inspection light C will travel through the transparent support plate 11 while being totally reflected at the upper and lower boundary surfaces of the transparent support plate 11.

In the case of this embodiment, one light source 12 is provided for a single entrance surface 16, but the invention is not limited to this, and it is also possible to set two or more entrance surfaces 16 and position the light sources facing each other. good.

Next, the imaging device 13 is disposed below the transparent support plate 11, and its field of view 19 is set so that the component 1 to be inspected can be observed through the transparent support plate 11. The image signal obtained by this imaging device 13 is given to an image processing device 14 and
After processing such as digitization is performed, the presence or absence of deformation of the lead 2 is inspected from the binary image to determine whether the component 1 is good or bad.

In the component inspection device configured as described above, after the component 1 to be inspected is placed on the support surface 15 of the transparent support plate 11 covered with the liquid film 24, the light source 12 and the imaging device 13 are activated to inspect the leads 2. Execute.

Assuming that the part 1 to be inspected is a defective product in which one lead 2' out of the many leads 2 is deformed, as shown in FIG.
However, the deformed lead 2' does not come into complete contact with the support surface 15 or the liquid film 24, and for example, its tip portion rises above the support surface 15.

In this case, even if the lead 2 is correct and the height varies and the lead 2 rises slightly above the support surface I5,
This minute gap is filled with the liquid film 24, and the error in the height of the lead 2 is absorbed.

After the inspection light C emitted from the light source 12 enters the transparent support plate 11, it travels through the transparent support plate 11 while being totally reflected. When C hits, the inspection light C is diffusely reflected at the contact portion, and the state of total reflection is disturbed. As a result, the diffusely reflected light d passes through the lower surface of the transparent support plate 11 and travels toward the imaging device 13, so that the diffusely reflected light d is observed by the imaging device 13, and a complete image of the lead 2 is generated.

5 and 6 illustrate the principle of the above-mentioned diffused reflection.

FIG. 5 shows a boundary surface 18 (
To be precise, this is an enlarged view of the state in which the inspection light C is incident on the interface 18 between the liquid film 24 and the outside air at an angle greater than the critical angle. This inspection light C is totally reflected at the boundary surface in one day, but
In this case, the inspection light C, as shown by P in the figure, has a reflection effect such that it returns from the outside air 17 into the transparent support plate 11 after protruding from the boundary surface 18 by the wavelength of the light. As a result, as shown in FIG.
When the object 20 is in contact with the object 20, the protruding inspection light C is diffusely reflected by the rough surface 21 of the object 20, resulting in the phenomenon described above.

Next, when the inspection light C reaches the part of the lead 2' where the floating occurs, the inspection light C is diffusely reflected at the base end of the lead 2' that comes into contact with the support surface 15 or the liquid film 24. At the tip of the lead 2', the inspection light C is totally reflected at the boundary surface and passes through the transparent support plate 11. Therefore, only the diffusely reflected light d at the base end portion is observed by the imaging device 13, and an incomplete image of the lead 2' is generated.

FIG. 3 shows the image 22 in the above setting example,
23 shows the complete image part of lead 2 without floating; 2
3' indicates an incomplete image portion of the lead 2' that is raised. Therefore, it is possible to determine whether the component 1 is good or bad depending on whether an appropriate lead image is obtained.

<Effects of the Invention> As described above, the present invention supports the inspection component on the support surface of the transparent support plate, projects inspection light from the incident surface on the outer periphery, and propagates through the transparent support plate by repeating total reflection. Since the part to be inspected is observed from below the transparent support plate through the transparent support plate, the inspection light is diffusely reflected at the part to be inspected that comes into contact with the support surface. The diffusely reflected light is not generated for inspection parts that do not come into contact with each other, and it is possible to easily determine whether the inspection part is good or bad.

According to the component inspection device of the second type, there is no need for accurate positioning of the component during inspection, and component inspection can be started with almost no effort required for inspection preparation, making it possible to achieve highly accurate and highly efficient inspection. In addition, since a liquid film is provided on the supporting surface, it is possible to inspect parts with multiple leads.
Even if there is a variation in the height of the leads, the error is absorbed by the liquid film, so proper inspection can be performed without the need for operations such as pressing the component against the support surface. Furthermore, since the presence of the liquid film increases the contact area with the support surface, a clear image can be obtained and inspection accuracy can be improved. Furthermore, even if there are scratches on the support surface, the scratches are filled with the liquid film, so that it is possible to prevent the scratches from being mistakenly observed as leads, which has many remarkable effects.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a schematic configuration of a parts inspection apparatus according to an embodiment of the present invention. FIG. 2 is a front view showing an enlarged inspection situation of parts, and FIG. FIG. 4 is an explanatory diagram showing an example of the obtained image; FIG. 4 is an explanatory diagram for explaining the principle of total reflection of light; FIGS. 5 and 6 are explanatory diagrams for explaining the invention in detail; FIG. 7 is a front view showing an example of a component to be inspected, and FIG. 8 is a plan view showing an example of a conventional component inspection apparatus. 10...Component inspection device 11...Transparent support plate 12...Light source 13...Damage device 24...Liquid film

Claims (1)

[Claims] A component inspection device having a transparent support plate, a light source, and an imaging device, wherein the transparent support plate has an upper surface as a support surface for supporting the inspection component, and a liquid film is provided on the support surface, Either end surface of the outer periphery is set as an incident surface for the inspection light, a light source is placed facing the incident surface, and the projection direction of the inspection light is set so that the inspection light travels through the transparent support plate by repeating total reflection. A component inspection device, wherein the imaging device is disposed below the transparent support plate, and a field of view is set such that the inspection component can be observed through the transparent support plate.