JP3236330B2 - Cream solder quality judgment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for judging the quality of cream solder, and more particularly, to a method in which a range where an irradiation light of a projector and a visual field of a camera intersects with a permissible range of cream solder height above a substrate. And by obtaining the image of the camera,
The present invention relates to means for accurately and quickly measuring the volume of cream solder.

[0002]

2. Description of the Related Art Prior to mounting electronic components on a substrate, cream solder is generally applied to the electrodes of the circuit pattern on the substrate by a screen printing apparatus. In this screen printing, cream solder is applied through the pattern holes by moving a screen mask having a pattern hole close to the upper surface of the substrate and sliding a squeegee on the screen mask, and then separating the screen mask from the substrate. By doing so, the cream solder in the pattern hole is transferred onto the electrode.

[0003] However, the cream solder in the pattern hole is not always completely transferred. For example,
When the pattern holes are clogged or the cream solder oozes to the back surface of the screen mask, the volume of the cream solder on the electrode may be insufficient, or may be excessive.

Therefore, regarding this cream solder,
It is necessary to measure the volume accurately and quickly to determine the quality of the solder application. However, at present, this measurement is generally performed by visual observation and lacks accuracy. Then, as a measuring means without visual observation, a means by laser triangulation is known.

[0005]

However, laser triangulation can basically only measure the height of one point. Therefore, in order to measure the height of all points on the surface of the cream solder having irregularities on the surface with sufficient accuracy, for example, scanning along the longitudinal direction of the cream solder needs to be repeated very many times in a direction perpendicular to the longitudinal direction. Therefore, there is a problem that this method requires a lot of time for the measurement and is difficult to put to practical use.

SUMMARY OF THE INVENTION It is an object of the present invention to provide means for quickly determining the quality of cream solder.

[0007]

SUMMARY OF THE INVENTION According to the present invention, an illumination light of a projector and a visual field of a camera intersect above a substrate.
A floodlight and a camera are provided, and apertures are provided for each of the floodlight and the camera.The intersection between the upper limit of the irradiation light of the floodlight and the upper limit of the field of view of the camera matches the upper limit of the height of the cream solder. The intersection point between the lower limit of the irradiation light of (1) and the lower limit of the field of view of the camera is made to coincide with the lower limit of the height of the cream solder.

[0008]

According to the above construction, when the surface of the cream solder is below the lower limit of the height of the cream solder and the volume of the cream solder is insufficient, the irradiation light from the light emitter is applied to the surface of the cream solder. , The reflected light does not enter the visual field of the camera, so that the reflected light is not taken into the visual field of the camera. Therefore, the image of the camera is dark and the state of the solder is determined to be defective.

When the height of the surface of the cream solder is between the lower limit and the upper limit and the volume of the cream solder is appropriate, the irradiation light from the light projector hits the surface of the cream solder and its reflection occurs. As the light enters the field of view of the camera, this reflected light is captured by the camera. Therefore, the image of the camera is bright, and it is determined that the state of the solder is good.

When the surface of the cream solder is above the upper limit of the height of the cream solder and the volume of the cream solder is excessive, even if the irradiation light from the light projector hits the surface of the cream solder, Since the reflected light does not enter the field of view of the camera, the reflected light is not captured by the camera. Therefore, the image of the camera is dark and the state of the solder is determined to be defective.

[0011]

Next, embodiments of the present invention will be described with reference to the drawings. 1 is a front view of the apparatus, FIG. 2 is an enlarged view, and FIG. 3 shows an example of a camera image.

In FIG. 1, 1 is a substrate, 2 is an electrode formed on the upper surface of the substrate 1, and 3 is a cream solder applied to the upper surface of the electrode 2 by a screen printing apparatus. The substrate 1 is supported by an X table 4 and a Y table 5 placed on a support frame FR. MX and MY are X
These are drive motors of the table 4 and the Y table 5, respectively.

Reference numeral 6 denotes a Z table provided on the upper part of the support frame FR so as to be able to move up and down, and MZ denotes a motor for driving the Z table. On the lower left side of the Z table 6, a light projector 7 and a laser irradiator 8 facing the substrate 1 are attached by a bracket 6a. On the lower right side of the Z table 6, a camera 9 and a light receiver 10 facing the substrate 1 are mounted by a bracket 6b. The irradiation light (slit light wide in the X direction) of the light projector 7 and the field of view of the camera 9 intersect above the substrate 1.

Here, the laser beam B emitted from the laser irradiator 8 is reflected at the position Q immediately before the cream solder 3 on the substrate 1 and is taken into the light receiver 10, and the height of the upper surface of the substrate 1 is reduced. Measured. If the substrate 1 has a warp or the like and the height is different from the predetermined height, the Z-table driving motor MZ is driven to correct the height, and the height of the Z-table 6, The height of the projector 7 and the camera 9 with respect to the upper surface of the camera is made constant.

The light projector 7 and the camera 9 are not moved in the X and Y directions.
The substrate 1 moves in the X and Y directions. Specifically, by driving the motors MX and MY, the substrate 1 can be moved in the XY directions with respect to the projector 7 and the camera 9.

As described above, the light projector 7 emits irradiation light from above the substrate 1, and the camera 9 emits reflected light from the substrate 1 side.
The light enters above the substrate 1. Also, the floodlight 7,
The camera 9 is provided with apertures 7a and 9a, respectively.

As shown in FIG. 2, an intersection P between the upper limit a1 of the irradiation light of the projector 7 and the upper limit b1 of the field of view of the camera 9 is obtained.
1 is made equal to the upper limit of the allowable height of the cream solder 3 (the height Hmax from the upper surface of the substrate 1). Further, the intersection P2 between the lower limit a2 of the irradiation light of the projector 7 and the lower limit b2 of the field of view of the camera 9 is made to coincide with the lower limit of the allowable height of the cream solder 3 (the height Hmin from the upper surface of the substrate 1). Specifically, when the positional relationship is as shown in FIG. 2, θ1 = arctan (Y7 / (H7−Hmax)) − arctan (Y7 / (H7−Hmin)) θ2 = arctan (Y9 / (H9− Hmax)) − arctan (Y9 / (H9−Hmin)), so that the YZ of the projector 7 and the camera 9 are satisfied.
The position in the direction and the apertures 7a and 9a may be adjusted. Here, Y7 and Y9 are distances in the Y direction from the respective projectors 7 and 9 to the intersections P1 and P2, H7 and H9 are heights from the upper surface of the substrate 1 to the respective projectors 7 and the camera 9, and θ1 is a projector. 7, the angle formed by the upper limit a1 and the lower limit a2 of the irradiation light, and θ2 is the angle formed by the upper limit b1 and the lower limit b2 of the field of view of the camera 9.

The present apparatus is configured as described above. Next, the determination of the quality of the cream solder by the present apparatus will be described. First, the position Q immediately before the cream solder 3 to be determined.
The height of the (upper surface of the substrate 1) is measured by the laser irradiator 8 and the light receiver 10, and if the substrate 1 is warped, the motor MZ is driven so that the projector 7 and the camera 9 Is corrected in the Z direction so as to be located at the predetermined heights H7 and H9 from the upper surface of. At the same time, the motors MX and MY are driven to move the substrate 1 relatively in the XY directions with respect to the projector 7 and the camera 9, and the camera 9 captures an image.

FIG. 3 shows three cream solders 3
Shows the captured image. H0 is cream solder 3
Height H1 that is smaller than the lower limit Hmin of the allowable height range
Is a height between the upper limit Hmax and the lower limit Hmin, H
2 is a height that is larger than the upper limit Hmax. In FIG. 3, a hatched portion indicates that the image is dark, and a portion without the hatched portion indicates that the image is bright. Note that the positions and shapes of these three cream solders 3 in the image are known.

The image of the cream solder 3 having the height H1 is bright. This is because the height H1 is between the upper limit Hmax and the lower limit Hmin, so that the irradiation light of the projector 7 hits the surface of the cream solder 3 and the reflected light can pass through the visual field of the camera 9. The volume V of this cream solder 3 is SHmin ≦ V ≦ SHmax
(Where S is the area of the cream solder 3 and this S is known), and the application state is determined to be good.

The images of the two cream solders 3 having the heights H0 and H2 are dark. This is the height H0
Is too low, and height H2 is too high.
This is because even if the irradiated light hits the surface of the cream solder 3, the reflected light does not enter the visual field of the camera 9, and the reflected light is not taken into the camera 9. In these cases, the volume of the cream solder 3 is SHmin ≦ V ≦ S
It is not in the range of Hmax, and the application state is determined to be defective (no).

As described above, according to this means, since the wide slit light is used, it is not necessary to repeat scanning many times, and it is possible to judge the quality of the application of the cream solder 3 only by the image of the camera 9. Therefore, quick quality judgment can be realized.

[0023]

According to the present invention, a projector and a camera are provided so that the irradiation light of the projector and the field of view of the camera intersect above the substrate, and apertures are provided for each of the projector and the camera. The intersection of the upper limit of the irradiation light of the above and the upper limit of the field of view of this camera is matched with the upper limit of the height of the cream solder,
Since the intersection of the lower limit of the irradiation light of this projector and the lower limit of the field of view of this camera was matched with the lower limit of the height of the cream solder,
The brightness of the image of the camera obtained by a small number of scans immediately indicates whether the volume of the cream solder is within a predetermined range, and the quality of the solder is quickly determined only by the brightness of the image. be able to.

[Brief description of the drawings]

FIG. 1 is a front view of the apparatus of the present invention.

FIG. 2 is an enlarged view of the same.

FIG. 3 is an explanatory view of the camera image.

[Explanation of symbols]

 Reference Signs List 1 board 3 cream solder 7 projector 7a aperture 9 camera 9a aperture a1 upper limit of irradiation light a2 lower limit of irradiation light b1 upper limit of field of view b2 lower limit of field of view Hmax upper limit of cream solder Hmin lower limit of cream solder

Claims (1)

(57) [Claims] A projector and a camera are provided so that the irradiation light of the projector and the visual field of the camera intersect above the substrate, and apertures are provided for each of the projector and the camera so that the irradiation light of the projector is The intersection of the upper limit with the upper limit of the field of view of this camera is matched with the upper limit of the height of the cream solder, and the intersection of the lower limit of the irradiation light of this projector and the lower limit of the field of view of the camera is matched with the lower limit of the cream solder height An apparatus for judging the quality of a cream solder.