JPS62132400A - Inspection of mounting situation of electronic parts - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for inspecting the mounting status of electronic components, which mainly involves inspecting whether a chip-shaped electronic component is properly or improperly mounted on a board surface. It is.

Conventional technology Conventionally, this type of mounting status inspection method uses a loussesor to grasp the contrast between the components and the board, or by applying white silk to the parts where the electronic components are mounted on the printed circuit board to detect misalignment of the mounting position of the electronic components and parts. There are known means for determining the presence or absence of

Problems to be Solved by the Invention However, these methods cannot necessarily accurately determine the mounting status of electronic components.

Means for Solving the Problems In the electronic component mounting status inspection method according to the present invention,
Light is irradiated from above the board on which electronic components are mounted to cast a shadow on the edge of the electronic component, and the contrast of the shadow is determined in a limited manner at several points along the periphery of the electronic component, and these limited contrasts are determined in advance. The mounting status of electronic components is determined based on whether or not the electronic component is within the specified range.

Function: In this method for inspecting the mounting status of electronic components, the shape of the electronic component is depicted as a shadow caused by irradiation of light, and the contrast of the shadow is determined at several points along the periphery of the electronic component. Since the mounting status of electronic components is inspected to see if it is within a predetermined range, it is possible to accurately and easily determine whether the mounting status of electronic components is appropriate.

Embodiments will now be described with reference to the accompanying drawings.

This method for inspecting the mounting status of electronic components is applied to inspecting not only whether a chip-shaped electronic component is mounted on a board but also whether it is mounted accurately at a desired position. Conceptually, the method is as shown in Figure 1, where a strobe light is applied to the electronic component E mounted on the board P from above.
, S..., etc., the irradiation of the light casts a shadow on the edge of the electronic component E, and the contrast of this shadow is grasped at several points in the image taken by camera C, and the contrast is determined. The suitability of the mounting situation of the electronic component E is determined based on whether or not the value is within a predetermined range. In this method, limited grasping of shadows is performed by creating a window that limits the grasping area to a predetermined position and several locations in the image along the periphery of the electronic component, and within that window, the component body and surrounding positions are depicted as shadows. Alternatively, the positional relationship between the electronic component side and the substrate surface can be determined from the difference in contrast between the electrode terminal and the peripheral position.

For example, in the case of a rectangular chip component e1, a shadow 10 is created around the periphery when irradiated with light, as shown in FIG. The screen of the camera that projects the shadow is provided with windows 11 to 16 that limit the shadow to the top, bottom, left and right along the desired mounting position, so that the shadow projected through the camera is superimposed on the screen, and the chip components e.
By scanning the color contrast from the main body side of 1, the boundary between the chip component el and the shadow is detected. This detection is performed for each of the windows 11 to 16 to determine the outline of the frame, and if the center value deviates from the original point by more than a preset value, it can be determined that the mounting is inappropriate.

Furthermore, in the case of a chip-type transistor e2 with protruding electrodes as shown in FIG. 3, each electrode t.

If windows 21 to 23 are provided corresponding to the predetermined positions of ~t3, and the proportion of reflected light from the surrounding shadows 20 and electrodes located within these windows 21 to 23 is counted by the number of pixels, the mounting status of electronic components can be determined. can be determined.

Similarly, in the case of part e3 such as cylindrical C/R,
Electrodes t4 on both sides as shown in FIG.

Since t5 reflects the strobe light within the shadow 30 generated around it, the edges of the windows 31 and 32 and the chip component e
The implementation status can be determined based on the correlation with 3 Shining Edge. In this inspection, when the edge of chip component e3 can be detected in each window 31.32 and the two edges do not overlap, it can be determined that the state is proper. Window 31.3 or any edge
If it cannot be detected within 2, it can be determined that the implementation is inappropriate.

Note that when no shadow is produced by light irradiation, it can be determined that no electronic component is attached.

Effects of the Invention As described above, according to the method for inspecting the mounting status of electronic components according to the present invention, the mounting status of the electronic components can be determined based on the contrast of the shadows generated around the electronic components by light irradiation. It becomes possible to very easily determine the exact mounting status based on the shape.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of a mechanism to which an inspection method according to the present invention is applied, and FIGS. 2 to 4 are explanatory diagrams of a mounting status determination process according to a component shape by the same inspection method. E (e, le2, e3): electronic component, P: board, S
, S...: Light source such as strobe, 10°20.30: Shadow, 11-16.21 to 23.31.32: Window that limits the contrast of the shadow.

Claims (1)

[Claims] Light is irradiated from above the board on which electronic components are mounted to cast a shadow on the edge of the electronic component, and the contrast of the shadow is determined in a limited manner at several points along the periphery of the electronic component, and these limited contrasts are determined in advance. A method for inspecting a mounting status of an electronic component, characterized in that the mounting status of the electronic component is determined based on whether or not the electronic component is within a certain range.