JPH0282105A - Three-dimensional shape inspecting instrument - Google Patents

Abstract

PURPOSE:To improve the efficiency and reliability of inspection by inspecting the three-dimensional shape of an object to be inspected according to images of the brightness and height of the object of inspection displayed in the same image by measurement positions. CONSTITUTION:An optical system 13 outputs two kinds of detection signals i1 and i2 corresponding to the position and intensity of light incident on a photodetector 15. Then a signal processing circuit 16 computes the height and brightness of the object 11 to be inspected according to the signals i1 and i2 and their data SH and SB are stored in corresponding memory areas of a height image memory 17 and a brightness image memory 18 according to the X coordinate of an optical scanning system and Y-coordinate information from a stage 12. Then a shading detecting circuit 19 refers to the height data stored in the memory 17 to calculate shading length based upon the heigh of a chip component included in the object 11. Then a shading composing circuit 20 makes a display 21 of a shading image in a color different from a peripheral part in the direction where the chip component is shaded according to the shading length calculated by the circuit 18 and the brightness data stored in the memory 18.

Description

[Detailed Description of the Invention] [(Summary) A three-dimensional shape inspection device, in particular, a three-dimensional shape inspection device that uses both an image indicating the brightness and an image indicating the height of a chip component such as a circuit element mounted on the surface of a substrate. Regarding technology for inspecting the mounting state of chip components, the purpose of this technology is to enable efficient observation of brightness images and height images of the inspection target, thereby contributing to efficiency of inspection and improvement of reliability. an optical system that optically measures the three-dimensional shape of the inspection target and outputs a signal indicating the shape; and height data and brightness data of the inspection target using the signals output from the optical system. a signal processing circuit that calculates the calculated data in a corresponding storage area in the image memory;
An image in which a shaded area based on the height of the inspection object is detected by referring to the height data in the image memory, and an image of the detected shaded area is superimposed on an image according to the brightness data of the corresponding measurement position. It is equipped with a synthesis circuit and a display device that displays the image created in the image synthesis circuit, and displays images of brightness and height for each measurement position of the inspection target displayed on the same image on the display device. The configuration is configured to inspect the three-dimensional shape of the inspection object based on the inspection target.

[Industrial application field]

The present invention relates to a three-dimensional shape inspection device, and more specifically,
Using both an image indicating the brightness and an image indicating the height of a chip component such as a circuit element mounted on the surface of a board, it is possible to determine the mounting state of the chip component, such as whether there is no chip, misalignment, mounting direction, etc. Related to technology for inspecting defects such as chipping and lifting.

[Conventional technology]

FIG. 5 shows an example of the configuration of a conventional three-dimensional shape inspection device.

In the figure, 51 is an object to be inspected (in this case, a printed circuit board on which a plurality of chip components are mounted), and 52 is an object that optically measures the three-dimensional shape of the object to be inspected 51 and outputs a signal indicating the shape. an optical system; 53 is a signal processing circuit that calculates height data and brightness data of the inspection object using the signals output from the optical system; 54 and 55 each calculate data calculated in the signal processing circuit 53 (each S , ,S) for storing the images in the corresponding storage areas, 56 and 57 store the data read from the corresponding memories as height images and brightness images, respectively. 5 shows a height display device and a brightness display device for display, and a control section for controlling the operation of each of the above circuits.

In the apparatus shown in FIG. 5, the operator inspects the presence, chipping, lifting, etc. of chip components while observing both the height image and the brightness image displayed on the two display devices 56 and 57, respectively. It is designed to judge the quality of chip parts.

FIG. 6 shows another example of the configuration of a conventional three-dimensional shape inspection device.

The configurational limits of the device shown in this figure and the device shown in FIG. 5 are as follows:
■ One display device 60 is used instead of the two display devices 56 and 57; ■ The image switching circuit 59 is used to switch the image displayed on the display device 60 between a height image and a brightness image. What I did, ■Optical system 52
A PSD (Positive Sensitive Device;
Po5ition 5ensitiviveDev 1ce
) 52b is used. in this case,
The optical system 52a outputs two types of detection signals 11 and 12 depending on the position and intensity of the light incident on the PSD 52b. Regarding the optical system using this PSD, the specification (Japanese Patent Application No. 63-1448) already filed by the present applicant
No. 46). Note that the other configurations and operations are the same as those of the device shown in FIG. 5, so their explanation will be omitted.

[Problem to be solved by the invention]

FIG. 7 shows an example of a display image in the conventional example, for example, the fifth
An example of an image displayed on display devices 56 and 57 in the figure device is shown. In the figure, (a) shows an example of a brightness image, and (b) shows a height image at that time.

In FIG. 7(a), relatively bright parts are shown darker, and relatively dark parts are shown more whitish. In this case, the parts of the board around each chip component are usually dark, so the black chip part indicated by A in the figure is very difficult to observe because it is dark just like the part of the board around it. .

On the other hand, in FIG. 7(b), relatively high parts are shown darker, and relatively low parts are shown more whitish. In this case, the chip component designated by A is higher than the substrate and can therefore be identified.

However, the brightness of the chip cannot be determined from this height image. Therefore, the operator must judge the quality of the chip component while observing both the brightness image shown in FIG. 7(a) and the height image shown in FIG. 7(b).

In this way, with conventional equipment, it is necessary to observe brightness images and height images alternately, which makes searching for the corresponding chip complicated and extremely inconvenient. The efficiency of testing is reduced; ■Some chip parts, such as those in A, are difficult to distinguish from the board in the brightness image, which impairs the reliability of inspection.
There was a drawback.

The present invention was created in view of the problems in the prior art, and enables efficient observation of brightness images and height images of an inspection target, which in turn can contribute to improved efficiency and reliability of inspection. The purpose is to provide a three-dimensional shape inspection device.

(Means for Solving the Problem) When an object is observed from an oblique direction, the size of the shaded area that appears there changes depending on the height of the object. Therefore, in the present invention, this feature is utilized to display a shadow image corresponding to the height of the object adjacent to the object in the brightness image. In particular, when using an optical system based on laser beam scanning and triangulation, there are blind spots (shaded areas) in the brightness image where brightness cannot be detected, and the shaded areas have a different color from the others. Even if the height is displayed, the original brightness image is not affected.

Therefore, the three-dimensional shape inspection apparatus according to the present invention, as shown in the principle block diagram of FIG. An optical system 3 that outputs S0 and a signal output from the optical system are used to calculate height data S1 and brightness data S2 of the inspection object, and the calculated data are transferred to the corresponding data in the image memory. A signal processing circuit 4 stored in a storage area and a shadow portion based on the height of the inspection object are detected by referring to the height data in the image memory, and an image I of the detected shadow portion is correspondingly generated. It is equipped with an image synthesis circuit 5 that overlaps the image I2 according to the brightness data of the measurement position, and a display device 6 that displays the image created in the image synthesis circuit, and displays the images on the same image on the display device. The present invention is characterized in that the three-dimensional shape of the object to be inspected is inspected based on images of brightness and height at each measurement position of the object to be inspected.

[Operation] According to the above-described configuration, images of brightness and height for each measurement position of the inspection target can be observed on the same image on the display device.

Therefore, it is possible to eliminate the troublesome effort of having to observe two images alternately as in the conventional type, thereby making it possible to improve the efficiency of the inspection.

In addition, even in situations where it is difficult to distinguish parts of the brightness image from other parts with similar brightness, by referring to the image of the corresponding height (image of the shaded part), the inspection target can be easily identified. The three-dimensional shape of can be inspected. This contributes to improving the reliability of testing.

Note that other structural features and details of the operation of the present invention will be explained using the embodiments described below with reference to the accompanying drawings.

〔Example〕

FIG. 2 partially schematically shows the configuration of an embodiment of the present invention in the form of a block diagram.

In the figure, 11 is a printed circuit board on which a plurality of chip components to be inspected are mounted, 12 is a stage for mounting the inspection object, and 13 is an optical system for irradiating the inspection object with a light beam. A light source 14 such as a semiconductor laser, a collimating lens, a deflection mirror (not shown), etc. for scanning the light beam in the X-axis direction, and a photodetector 15 such as a PSD for detecting reflected light. Contains.

The optical system 13 outputs two types of detection signals i8.12 depending on the position and intensity of the light incident on the photodetector 15. Further, from the stage 12, a light beam is transmitted to the inspection target 11.
Information (Y coordinate information) indicating which position on the top is irradiated is output.

16 is a signal processing circuit, which outputs two types of detection signals jls
Calculate the height and brightness of the inspection target based on 1K, and calculate the calculated data (S and Ss, respectively)
Based on the X coordinate of the optical scanning system and the Y coordinate information from the stage 12, the height image memory 17 and the brightness image memo 1 are stored respectively.
Store in the memory area corresponding to month 8. In addition, the height SH and brightness SIl of the inspection object are respectively SH= (it iz) / (i++iz), S,
=t, +i,.

It is expressed as 22 is a control section for controlling the operation of each of the above circuits.

Reference numeral 19 denotes a shadow detection circuit that refers to the height data stored in the height image memory 17 and detects a shadow portion based on the height of each chip component included in the inspection object 11 ( It has a function (calculating the shaded area). Calculation of the shaded area is performed as follows (see FIG. 3). First, the shadow detection circuit 19 refers to the height data to determine the height h of each chip component. Here, if the observation direction of the optical system 13 for detecting height is inclined by an angle θ with respect to the vertical direction, then the length of the shaded part based on this is
is expressed as I=hXtanθ.

Reference numeral 20 denotes a shadow synthesis circuit, which calculates the shadow of each chip component on the brightness image based on the shadow area I=hXtanθ calculated in the shadow detection circuit 19 and the brightness data stored in the brightness image memory 18. It has a function of displaying a shaded image on the display device 21 using a color different from the display color of the peripheral portion in the direction in which it occurs. In other words, the shadow image corresponding to the height of the chip component is displayed on the same image as the brightness image of the chip component.

FIG. 4 shows an example of a display image according to the embodiment shown in FIG.

As shown in the figure, in addition to the brightness image of each chip component, a shaded image (blacked out portion) indicating the height of the corresponding chip component can be observed simultaneously.

Therefore, according to the present embodiment, the existence of the black chip component A, which was difficult to distinguish from the brightness image (see FIG. 7(a)) in the conventional example, can be easily recognized from the shadow image. It can be recognized, and furthermore, its height can be easily estimated from the length I of the shadow image and the observation direction angle θ of the optical system.

In this way, according to this embodiment, it is possible to eliminate the troublesome effort of having to observe height images and brightness images alternately, as seen in the conventional type, thereby improving the efficiency of inspection. can be achieved. In addition, even for chip parts whose brightness is difficult to distinguish in the brightness image, by referring to the corresponding height image (image of the shaded area), it is possible to inspect the presence of chip parts, chipping, lifting, etc. be able to. This contributes to improving the reliability of inspection.

In addition, if the display device 21 is a color display device in the above-described embodiment, a further display effect can be obtained by, for example, displaying the brightness image in shading and displaying the shaded area in a color such as red. .

〔Effect of the invention〕

As explained above, according to the present invention, the brightness image and the height image of the inspection target can be observed efficiently, that is, on the same image, thereby improving the efficiency and reliability of inspection. You can also aim for

[Brief explanation of the drawing]

FIG. 1 is a principle block diagram of a three-dimensional shape inspection device according to the present invention, FIG. 2 is a block diagram partially schematically showing the configuration of a three-dimensional shape inspection device as an embodiment of the present invention, and FIG. is the second
Figure 4 is a diagram showing an example of an image displayed on the display device in Figure 2. Figure 5 is a configuration of a conventional three-dimensional shape inspection device. FIG. 6 is a block diagram showing another configuration example of a conventional three-dimensional shape inspection device. FIGS. 7(a) and (b) are diagrams showing an example of a display image in the conventional example. , (a) is a brightness image, and (b) is a diagram showing a height image. (Explanation of symbols) 1... Image memory, 2... Inspection object, 3... Optical system, 4... Signal processing circuit, 5... Image synthesis circuit, 6
...Display device, So...Three-dimensional shape instruction signal, Sl
... Height data, S2 ... Brightness data, I, ...
・Image of the shaded area, 1□...Brightness image.

Claims (1)

[Claims] An image memory (1); an optical system (3) that optically measures the three-dimensional shape of the inspection object (2) and outputs a signal (S_0) indicating the shape; Signal processing that calculates height data (S_1) and brightness data (S_2) of the inspection target using signals output from the system, and stores the calculated data in the corresponding storage area in the image memory. a circuit (4); detecting a shaded area based on the height of the inspection object by referring to the height data in the image memory; and converting the image (I_1) of the detected shaded area to the brightness of the corresponding measurement position; an image synthesis circuit (5) that superimposes the image (I_2) according to the image data, and a display device (6) that displays the image created in the image synthesis circuit, and displays the image on the same image on the display device. A three-dimensional shape inspection apparatus, characterized in that the three-dimensional shape of the object to be inspected is inspected based on images of brightness and height at each measurement position of the object to be inspected.