JP4808072B2 - Filter checkered plate, three-dimensional measuring device and illumination means - Google Patents

Description

  The present invention relates to a three-dimensional measuring apparatus and an illuminating means for measuring a filter grid stripe plate, a three-dimensional shape of a measurement object, and the like using a phase shift method.

  In general, when an electronic component is mounted on a printed board, first, cream solder is printed on a predetermined electrode pattern provided on the printed board. Next, the electronic component is temporarily fixed on the printed circuit board based on the viscosity of the cream solder. Thereafter, the printed circuit board is guided to a reflow furnace, and soldering is performed through a predetermined reflow process. In recent years, it is necessary to inspect the printed state of cream solder in the previous stage of being guided to a reflow furnace, and a three-dimensional measuring device is sometimes used for such inspection.

  In recent years, various types of so-called non-contact type three-dimensional measuring devices using light have been proposed, and in particular, a technique relating to a three-dimensional measuring device using a phase shift method has been proposed (Japanese Patent Laid-Open No. 11-212443, patent). No. 2711042).

  A CCD camera is used in the three-dimensional measuring apparatus in the above technique. In other words, a light pattern having a striped light intensity distribution is irradiated onto a measurement object (in this case, a printed circuit board) by irradiation means comprising a combination of a light source and a sine wave pattern filter. And it observes using the CCD camera which has arrange | positioned the point on a board | substrate directly. In this case, the light intensity I at the point P on the screen is given by the following equation.

I = e + f · cos φ [where e: DC light noise (offset component), f: sine wave contrast (reflectance), φ: phase given by unevenness of object]
At this time, the light pattern is moved, the phase is changed in four steps (φ + 0, φ + π / 2, φ + π, φ + 3π / 2), and images having intensity distributions I0, I1, I2, and I3 corresponding to these are captured. The position information θ is obtained based on the following formula.

θ = arctan {(I3-I1) / (I0-I2)}
Using this position information θ, the three-dimensional coordinates (X, Y, Z) of the point P on the printed circuit board (cream solder) are obtained, and the three-dimensional shape, particularly the height of the cream solder is measured.

  By the way, in the three-dimensional measuring apparatus according to the above technique, it is necessary to change the phase into four stages and acquire four kinds of images having an intensity distribution corresponding to each stage. That is, every time the phase is changed, imaging must be performed, and as a result, imaging needs to be performed four times for one point. For this reason, time is required for imaging, and as a result, the time from the start to the end of measurement may be long.

  The present invention has been made in view of the above circumstances, and is capable of reducing the time required for measurement when measuring the three-dimensional shape of a measurement object using the phase shift method. One of the main purposes is to provide an original measuring device and illumination means.

  Characteristic means capable of achieving the above object will be described below. For each means, characteristic actions and effects are described as necessary.

  Means 1. Uniform light illumination that can irradiate the measurement object and surrounding non-measurement objects substantially uniformly, and at least the measurement object has a striped light intensity distribution and different wavelength components. Irradiating means capable of simultaneously irradiating at least two light component patterns having different relative phase relationships with each other; and the reflected light from the measurement object irradiated with the uniform light and the surrounding non-measurement object; and Based on imaging means capable of separating and imaging reflected light from a measurement object irradiated with at least the light component pattern for each light component, and image data based on uniform light imaged by the imaging means Based on at least two types of image data captured for each light component by the image capturing unit, the region extracting unit for extracting the region where the object exists, and at least the region extracting unit Three-dimensional measuring apparatus characterized by comprising a calculating means for calculating a predetermined height of the extracted measurement object in stationary areas.

  According to the means 1, substantially uniform light is irradiated to the measurement object and the surrounding non-measurement objects by uniform light illumination. The reflected light from the measurement object irradiated with the substantially uniform light and the surrounding non-measurement object is imaged by the imaging means, thereby obtaining image data. Based on the image data, the region where the measurement object exists is extracted by the region extracting means. In this case, the region of the measurement target can be reliably identified by the difference in the degree of reflection between the measurement target and the non-measurement target. In addition, at least two light component patterns are simultaneously irradiated onto the measurement object by the irradiation unit. Here, each light component pattern has a striped light intensity distribution, has different wavelength components, and has a different relative phase relationship. Then, the reflected light from the measurement object irradiated with the light component pattern is separated and imaged for each light component by the imaging means. Further, based on at least two types of image data captured by the imaging unit under the different relative phase relationships, the calculation unit calculates at least a predetermined height of the measurement object. Therefore, unlike the prior art in which it is necessary to perform imaging every time the relative phase relationship is changed, it is possible to perform imaging for each light component under different relative phase relationships. For this reason, the time required for irradiation and imaging with respect to one point is remarkably shortened, so that the time required for measurement can be drastically reduced. In addition, in the calculation, the region of the measurement object has already been extracted and specified. Therefore, it is not necessary to perform correction calculation in consideration of non-measurement objects. As a result, it is possible to simplify calculations, increase the size of equipment for correction, prevent complications, and the like.

  Mean 2. The three-dimensional measuring apparatus according to claim 1, wherein the uniform light illumination is white light illumination capable of emitting white light.

  According to the means 2, by using white light illumination, if the measurement object and the non-measurement object are colored differently, the difference in reflected light is likely to appear not only in luminance but also in color difference. Therefore, when extracting the region where the measurement object exists by the region extraction means, the region of the measurement object is determined by the difference in brightness of reflected light or the difference in color between the measurement object and the non-measurement object. Certainly can be identified.

  Means 3. White light illumination capable of irradiating white light to a measurement object and surrounding non-measurement objects, and at least the measurement object has a striped light intensity distribution and different wavelength components from each other. Irradiating means capable of simultaneously irradiating at least three light component patterns having different relative phase relationships with each other; and the reflected light from the measurement object irradiated with the white light and the surrounding non-measurement object; and Based on image data obtained by separating at least the reflected light from the measurement object irradiated with the light component pattern for each light component, and image data of white light imaged by the imaging means, the measurement Based on at least three types of image data captured for each light component by the image capturing unit, a region extracting unit that extracts a region where the object is present, and at least a previous one using a phase shift method Three-dimensional measuring apparatus characterized by comprising a calculating means for calculating a predetermined height of the extracted measured object existing region in region extracting means.

  According to the means 3, the white light is irradiated to the measurement object and the surrounding non-measurement objects by the white light illumination. The reflected light from the measurement object irradiated with the white light and the surrounding non-measurement object is imaged by the imaging means, thereby obtaining image data. Based on the image data, the region where the measurement object exists is extracted by the region extracting means. In this case, the region of the measurement target can be reliably identified by the difference in the degree of reflection between the measurement target and the non-measurement target. In addition, at least the measurement object is simultaneously irradiated with a plurality of light component patterns by the irradiation means. Here, each light component pattern has a striped light intensity distribution, has different wavelength components, and has a different relative phase relationship. Then, the reflected light from the measurement object irradiated with the light component pattern is separated and imaged for each light component by the imaging means. Further, based on a plurality of image data picked up by the image pickup means under the different relative phase relationships, the calculation means calculates at least a predetermined height of the measurement object by a phase shift method. Therefore, unlike the prior art in which it is necessary to perform imaging every time the relative phase relationship is changed, it is possible to perform imaging for each light component under different relative phase relationships. For this reason, the time required for irradiation and imaging with respect to one point is remarkably shortened, so that the time required for measurement can be drastically reduced. In addition, in the calculation, the region of the measurement object has already been extracted and specified. Therefore, it is not necessary to perform correction calculation in consideration of non-measurement objects. As a result, it is possible to simplify calculations, increase the size of equipment for correction, prevent complications, and the like.

  Means 4. The said area extraction means extracts the area | region where the said measurement target object exists based on the difference of the brightness | luminance of the said measurement target object and the said non-measurement target object in any one of the means 1 thru | or 3 characterized by the above-mentioned. 3D measuring device.

  According to the means 4, the area where the measurement object is present is extracted from the image data by the area extraction means based on the difference in luminance between the measurement object and the non-measurement object. For this reason, regardless of the color of the surface of the measurement object or non-measurement object, the region can be extracted by a relatively easy process that only compares the luminance.

  Means 5. An irradiation direction of the measurement object and the non-measurement object by the white light illumination is different from an imaging direction of the measurement object and the non-measurement object by the imaging unit. The three-dimensional measuring apparatus described.

  According to the means 5, the angle differs between the irradiation direction and the imaging direction with respect to the measurement object and the non-measurement object. Therefore, the reflection angle of the irradiated white light varies depending on the surface state of the irradiated object. For this reason, the area | region where a measurement target exists can be extracted more reliably using the brightness | luminance of the reflected light imaged with an imaging means differing with a measurement target and a non-measurement target.

  Means 6. The three-dimensional according to any one of means 1 to 3, wherein the region extracting means extracts a region where the measurement target exists based on a color difference between the measurement target and a non-measurement target. Measuring device.

  According to the means 6, the area where the measurement object exists is extracted from the image data by the area extraction means based on the color difference between the measurement object and the non-measurement object. For this reason, it is possible to extract a region by a relatively easy process of simply comparing the colors of the surfaces of the measurement object and non-measurement object.

  Mean 7 The irradiating means can irradiate at least three light component patterns at the same time, and the calculating means calculates based on three kinds of image data, and each of the different relative phase relationships is α, 0, When β is set, the calculation means uses V0, V1, V2 obtained by converting the luminance of the measurement unit obtained from the three types of image data into the same amplitude and the same offset component, and position information by the following equation (1). The three-dimensional measuring apparatus according to any one of means 1 to 6, wherein θ is obtained, and the predetermined height is calculated based on the position information θ.

手段７のように、さほど複雑でない数式に基づいて位置情報θを求めることができ、該位置情報θに基づき前記所定の高さを演算することができる。そのため、３通りの画像データに基づいて計測対象物の所定の高さを求めるに際し、演算が複雑になってしまうことによる遅延が生じない。

As in the means 7, the position information θ can be obtained based on a mathematical expression that is not so complicated, and the predetermined height can be calculated based on the position information θ. For this reason, when the predetermined height of the measurement object is obtained based on the three types of image data, there is no delay due to the complicated calculation.

  Means 8. The three-dimensional measuring apparatus according to claim 7, wherein the three light component patterns having different wavelength components are red, green, and blue light component patterns, respectively.

  According to the means 8, the wavelength ranges are unlikely to overlap and can be separated relatively easily for each light component in the imaging means. In addition, the irradiation means can be configured relatively easily.

  Means 9. The irradiating means shields light from the light source in a striped manner with respect to a predetermined wavelength component, and uses a filter lattice fringe plate that allows light transmission with respect to the remaining wavelength component, and thereby sets each light component pattern having a different relative phase relationship from each other. The three-dimensional measuring apparatus according to any one of means 1 to 8, further comprising a filter lattice stripe plate mechanism capable of transmitting light simultaneously.

  According to the means 9, the predetermined wavelength component is shielded in a stripe shape by the filter grid stripe plate, and the remaining wavelength component is allowed to transmit light. For this reason, for example, when a plurality of filter lattice stripe plates are combined, only light components are allowed to transmit light in a striped manner. The light components transmitted in a stripe form form a pattern close to a sine wave, and the light component patterns have different relative phase relationships. Therefore, the calculation of the predetermined height of the measurement object by the calculation means is performed more accurately.

Means 10. The irradiating means includes a filter checkered plate,
The filter grid stripe plate is composed of a single plate, and regions where light from a light source is transmitted only for a predetermined wavelength component are arranged in a stripe shape, and light component patterns having different relative phase relationships are simultaneously transmitted. The three-dimensional measuring apparatus according to any one of means 1 to 9, wherein the three-dimensional measuring apparatus is light capable.

  According to the means 10, the predetermined wavelength component is transmitted in a stripe pattern by the filter grid stripe plate. For this reason, the predetermined wavelength components transmitted in a stripe form form a light component pattern close to a sine wave having a relative phase relationship different from each other. Therefore, the calculation of the predetermined height of the measurement object by the calculation means is performed more accurately. Further, since the filter checkered plate is composed of a single plate, the illumination means can be designed relatively easily, and the size can be reduced and the cost can be reduced.

  Means 11. The irradiating means can simultaneously irradiate three light component patterns, and the filter lattice stripe plate transmits only the first wavelength component with respect to the first, second, and third wavelength components having different wavelength components. A first region that transmits only the first and second wavelength components, a third region that transmits only the second and third wavelength components, and a third wavelength component. The three-dimensional measuring apparatus according to claim 10, wherein the fourth region that transmits only the first region is arranged in a stripe pattern in order.

  According to the means 11, the filter lattice stripe plate alternately repeats the striped regions through which each wavelength component can be transmitted. For this reason, it is possible to reliably form a light component pattern close to a sine wave having a relative phase relationship different from each other for each wavelength component only by configuring four types of regions. Note that four or more types of regions may be configured as long as light component patterns close to sinusoidal waves having different relative phase relationships can be formed.

  Means 12. The three-dimensional measurement apparatus according to claim 11, wherein the first area is colored red, the second area is yellow, the third area is cyan, and the fourth area is blue. .

  According to the means 12, the filter lattice strips are arranged in a stripe pattern in the order of red, yellow, cyan, and blue. For this reason, red, green, and blue can be transmitted as three light component patterns having different wavelength components. Therefore, the wavelength regions are unlikely to overlap and can be separated relatively easily for each light component in the imaging means. In addition, the irradiation means can be configured relatively easily.

  Means 13. Light having a substantially uniform uniform wavelength component and light having a plurality of predetermined wavelength components having at least a striped light intensity distribution and different relative phase relationships with respect to the measurement target and surrounding non-measurement targets An irradiation unit capable of simultaneously irradiating a component pattern, and reflected light from a measurement object irradiated from the irradiation unit is separated for each light component of the uniform wavelength component and the plurality of predetermined wavelength components. Based on image data corresponding to a uniform wavelength component imaged by the imaging means, an area extracting means for extracting an area where the measurement object is present, and an image picked up separately by the imaging means And calculating means for calculating a predetermined height of the measurement object whose existence area is extracted by at least the area extracting means based on image data corresponding to a plurality of predetermined wavelength components. Three-dimensional measuring apparatus according to claim.

  According to the means 13, the light having a substantially uniform uniform wavelength component and a plurality of predetermined wavelength components having at least a striped light intensity distribution and different relative phase relationships are applied to the measurement object by the irradiation means. The light component pattern is simultaneously irradiated. For this reason, it is possible to irradiate each light component with only one irradiating means, and it is possible to prevent the apparatus from becoming large due to the provision of separate illumination. Further, the uniform wavelength component and a plurality of predetermined wavelength components are separated and imaged for each light component by the imaging means, and each image data can be obtained simultaneously by only one imaging. Then, based on the image data of the uniform wavelength component, the region where the measurement object exists is extracted by the region extracting means. In this case, the region of the measurement target can be reliably identified by the difference in the degree of reflection between the measurement target and the non-measurement target. Based on image data corresponding to a plurality of predetermined wavelength components separately imaged by the imaging unit, the calculation unit calculates at least a predetermined height of the measurement object. Therefore, unlike the prior art in which it is necessary to perform imaging every time the relative phase relationship is changed, it is possible to perform imaging for each light component under different relative phase relationships. Therefore, necessary image data can be obtained with one irradiation and imaging for one point. Accordingly, the time required for one point can be remarkably shortened, so that the time required for measurement can be drastically reduced. In addition, in the calculation, the region of the measurement object has already been extracted and specified. Therefore, it is not necessary to perform correction calculation in consideration of non-measurement objects. As a result, it is possible to simplify calculations, increase the size of equipment for correction, prevent complications, and the like.

  Means 14. The three-dimensional measuring apparatus according to claim 13, wherein a wavelength region of the uniform wavelength component and a wavelength region of the plurality of predetermined wavelength components are different.

  According to the means 14, since the wavelength region of the uniform wavelength component and the wavelength region of the plurality of predetermined wavelength components are different, the uniform wavelength component and the plurality of predetermined wavelength components are reliably separated for each light component. Can be imaged.

  Means 15. 15. The three-dimensional measuring apparatus according to any one of means 1 to 14, wherein the light component pattern has a substantially sinusoidal light intensity distribution.

  According to the means 15, since the light component pattern has a substantially sinusoidal light intensity distribution, the measurement accuracy can be further improved.

  Means 16. The three-dimensional measuring apparatus according to any one of means 1 to 15, further comprising a reference height measuring means for measuring a height of a reference surface serving as a reference for the height of the measurement object.

  According to the means 16, the height of the reference surface which is the reference for the height of the measurement object is measured by the reference height measuring means. For this reason, not only the height positional relationship of the measurement object with respect to the three-dimensional measurement apparatus but also the height (thickness) of the measurement object itself can be measured.

  Means 17. Any of means 1 to 16, wherein the measurement object is cream solder printed on a printed circuit board, and a determination means for determining whether the printing state is good or not from the area and height of the cream solder is provided. The three-dimensional measuring device described in 1.

  According to the means 17, the area and height of the cream solder printed on the printed circuit board are measured, and pass / fail determination is performed based on the measured value. For this reason, each said effect is show | played at the time of the measurement of a cream solder, and quality determination can be performed accurately.

  Means 18. Any of means 1 to 16, wherein the measurement object is a solder bump provided on a printed circuit board, and a determination means for determining the quality of the solder bump shape from the area and height of the solder bump is provided. The three-dimensional measuring apparatus described.

  According to the means 18, the area and height of the solder bump provided on the printed circuit board are measured, and pass / fail judgment is performed based on the measured value. For this reason, the above-mentioned effects can be achieved when solder bumps are measured, and the quality can be determined accurately.

  Means 19. A filter grid stripe plate used in a three-dimensional measuring apparatus, which is composed of a single plate-like body, shields light from a light source in a stripe shape for a predetermined wavelength component and allows light transmission for the remaining wavelength components. A filter checkered plate capable of simultaneously transmitting at least two light component patterns having different relative phase relationships.

  According to the means 19, the predetermined wavelength component is transmitted in a stripe pattern by the filter grid stripe plate. For this reason, the predetermined wavelength components transmitted in a stripe form form a light component pattern close to a sine wave having a relative phase relationship different from each other. In addition, since at least two light component patterns can be simultaneously transmitted with a single plate, the three-dimensional measurement apparatus can be designed relatively easily, and the size and cost can be reduced. The three-dimensional measuring device may be a “three-dimensional measuring device according to any one of means 1 to 18”.

  Means 20. The filter grid stripe plate transmits three light component patterns simultaneously, and transmits only the first and second wavelength components of the first, second, and third wavelength components having different wavelength components. 21. The filter grid stripe plate according to means 19, wherein the filter grid stripe plate has a configuration in which a first region that emits light and a second region that transmits only the second and third wavelength components are sequentially arranged in a stripe pattern.

  By arranging the first and second regions in order as in the means 20, the first and third wavelength components can be transmitted as a substantially sinusoidal light component pattern having different phases. Further, the second wavelength component is uniform over the entire area of the lattice fringes, and uniform light irradiation can be simultaneously performed in addition to the striped light component pattern.

  Means 21. 21. The filter checkered plate according to claim 20, wherein the first region is color-coded yellow and the second region is color-coded cyan.

  According to the means 21, the filter lattice strips are arranged in a stripe pattern in the order of yellow and cyan. Therefore, red and blue light can be transmitted as two light component patterns having different wavelength components. Therefore, it is possible to transmit the light component pattern in which the wavelength regions are difficult to overlap.

  Means 22. A filter grid stripe plate used in a three-dimensional measuring apparatus, which is composed of a single plate-like body, shields light from a light source in a stripe shape for a predetermined wavelength component and allows light transmission for the remaining wavelength components. A filter checkered plate capable of simultaneously transmitting at least three light component patterns having different relative phase relationships.

  According to the means 22, the predetermined wavelength component is transmitted in a stripe shape by the filter grid stripe plate. For this reason, the predetermined wavelength components transmitted in a stripe form form a light component pattern close to a sine wave having a relative phase relationship different from each other. In addition, since at least three light component patterns can be simultaneously transmitted with one plate, the three-dimensional measuring device can be designed relatively easily, and the size and cost can be reduced. The three-dimensional measuring device may be a “three-dimensional measuring device according to any one of means 1 to 18”.

  Means 23. The filter lattice stripe plate transmits three light component patterns simultaneously, and transmits only the first wavelength component of the first, second, and third wavelength components having different wavelength components from each other. 1 region, a second region that transmits only the first and second wavelength components, a third region that transmits only the second and third wavelength components, and only the third wavelength component The filter grid stripe plate according to means 22, wherein the light transmitting fourth region is arranged in a stripe pattern in order.

  By arranging the first to fourth regions in order as in the means 23, the first, second, and third wavelength components can be transmitted as a substantially sinusoidal light component pattern having different phases.

  Means 24. 24. The filter checkerboard according to claim 23, wherein the first area is colored red, the second area is yellow, the third area is cyan, and the fourth area is blue.

  According to the means 24, the filter checkered plates are arranged in a stripe pattern in the order of red, yellow, cyan, and blue. For this reason, red, green, and blue can be transmitted as three light component patterns having different wavelength components. Therefore, it is possible to transmit the light component pattern in which the wavelength regions are difficult to overlap.

  Means 25. A three-dimensional measuring apparatus comprising the filter checkered plate according to any one of the means 17 to 24.

  By providing the filter checkered plate like the means 25, the three-dimensional measuring device can be designed relatively easily.

  Means 26. An illumination unit comprising the filter checkered plate according to any one of the units 17 to 24.

  By providing the filter grid stripe plate as in the means 26, it is possible to relatively easily design an illuminating means that can irradiate a plurality of light component patterns having different wavelength components.

  Hereinafter, an embodiment will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram schematically illustrating a printing state inspection apparatus 1 including a three-dimensional measurement apparatus according to the present embodiment. As shown in the figure, the printing state inspection apparatus 1 includes a table 2 on which a printed board K printed with cream solder H as a measurement object is placed, and an obliquely upper surface with respect to the surface of the printed board K. Illumination device 3 constituting an irradiating means for irradiating a predetermined light component pattern, CCD camera 4 constituting an imaging means for imaging the irradiated portion on the printed circuit board K, and the surface of the printed circuit board K Are provided with a white light illumination L for irradiating white light and a laser pointer (not shown) for measuring a reference height. The cream solder H in the present embodiment is printed on an electrode pattern made of a copper foil provided on the printed board K.

  The table 2 is provided with motors 5 and 6, and the motors 5 and 6 allow the printed circuit board K placed on the table 2 to slide in any direction (X-axis direction and Y-axis direction). It is like that.

  The white light illumination L is provided above the printed circuit board K and below the CCD camera 4. Since the white light illumination L has a relatively large ring shape, it does not hinder the image pickup of the printed board K by the CCD camera 4. Moreover, the white light illumination L irradiates white light in the central direction of the white light illumination L and obliquely downward. That is, white light is irradiated from obliquely above the periphery of the printed board K.

  The illumination device 3 in the present embodiment emits light component patterns having different phases of red, green, and blue. More specifically, as shown in FIG. 2, the illuminating device 3 includes a light source 11, a condenser lens 12 that collects light from the light source 11, an irradiation lens 13, and a red light disposed between both lenses 12 and 13. , Green and blue filter checkered plates 14, 15, and 16. The red filter grid stripe plate 14 changes the degree of red in a sine wave shape (striped shape) depending on the part, and only the red component is shielded (transmitted) in a striped shape so that all the light in other wavelength ranges is transmitted. It comes to allow. Further, the green filter lattice stripe plate 15 has a green degree changed to a sine wave shape (striped shape) according to the portion, and only the green component is shielded (transmitted) in a striped shape so as to be totally transmitted in other wavelength regions. It is designed to allow light. However, the phase of the sine wave is shifted by a predetermined pitch (“π / 2” in the present embodiment) as compared with the red filter grating strip 14 (see FIG. 3). Further, the blue filter lattice stripe plate 16 has a blue degree varying in a sine wave shape (striped shape) depending on a part, and only the blue component is shielded (transmitted) in a striped shape so as to be totally transmissive in other wavelength regions. It is designed to allow light. However, the phase of the sine wave is shifted by a predetermined pitch (“π / 2” in the present embodiment) as compared with the green filter grating strip 15 (see FIG. 3). That is, the red, green, and blue filter lattice strips 14, 15, and 16 are bonded to each other with their phases shifted from each other by a predetermined pitch (of course, they may be separated from each other).

  Then, the light emitted from the light source 11 is irradiated on the printed circuit board K as a light component pattern as shown in FIG. 4 through the condenser lens 12, the respective color filter lattice stripe plates 14, 15, 16 and the irradiation lens 12. It has become so.

  The CCD camera 4 includes first to third dichroic mirrors 21, 22, and 23 and first to third imaging units 24, 25, and 26 corresponding thereto. That is, the first dichroic mirror 21 reflects light (corresponding to red light) within a predetermined wavelength range (corresponding to red light), and the first imaging unit 24 images the reflected light. Further, the second dichroic mirror 22 reflects light (corresponding to green light) within a predetermined wavelength range (transmits light of other wavelengths), and the second imaging unit 25 images the reflected light. Further, a third dichroic mirror (which may be a normal mirror) 23 reflects light (corresponding to blue light) within a predetermined wavelength range (transmits light of other wavelengths), and performs third imaging. The unit 26 images the reflected light. The CCD camera 4 can also perform general color imaging.

  In the present embodiment, as shown in FIGS. 1 and 2, the CCD camera 4, the illuminating device 3, the motors 5 and 6, and the white light illumination L are driven and controlled, and the image captured by the CCD camera 4 is captured. A control device 7 is provided for executing various calculations based on the data. That is, when the printed circuit board K is placed on the table 2, the control device 7 first drives and controls the motors 5 and 6 to move them to a predetermined position, thereby moving the printed circuit board K to the initial position. This initial position is, for example, one position in which the surface of the printed circuit board K is divided in advance with the size of the field of view of the CCD camera 4 as one unit.

  Further, the control device 7 drives and controls the white light illumination L to start white light irradiation. Then, the reflected light of white light in the direction of the CCD camera becomes less dark on the printed board K which is a plane. On the other hand, in the cream solder H having an uneven surface, the reflected light becomes brighter than the printed board K due to irregular reflection. While such irradiation is being performed, the control device 7 drives and controls the CCD camera 4 to simultaneously image the inspection area and obtain color image data (first imaging).

  Next, the illumination device 3 is driven and controlled to start irradiation of the light component pattern. At this time, since the light component pattern includes a plurality of wavelength regions having different phases at a predetermined pitch, it is not necessary to shift the phase by a predetermined pitch as in the prior art. Furthermore, while simultaneous irradiation is performed in which the phase of each light component pattern is shifted in this way, the control device 7 drives and controls the CCD camera 4 so that each of these wavelength ranges (the imaging units 24 to 24). 26) The inspection area portion is imaged at once, and image data for three screens is obtained (second imaging).

  Further, in order to determine the height of the cream solder H by driving and controlling the laser pointer, the height of the portion selected by the method described later as the reference height in the inspection area is measured.

  The control device 7 includes an image memory and stores image data sequentially. Based on the stored image data, the control device 7 performs various image processing. While the image processing is being performed, the control device 7 controls the motors 5 and 6 to move the table 2 to the next inspection area. The control device 7 also stores the image data here in the image memory. On the other hand, when the image processing in the image memory is once completed, since the next image data is already stored in the image memory, the control device 7 can quickly perform the next image processing. That is, in the inspection, the movement to the next inspection area (m + 1) and the image input are performed on the one hand, and the m-th image processing and comparison determination are performed on the other hand. Thereafter, the same parallel processing is repeated alternately until the inspection in all the inspection areas is completed. Thus, in the printing state inspection apparatus 1 according to the present embodiment, the printing state of the cream solder H on the printed circuit board K is changed by sequentially performing image processing while moving the inspection area under the control of the control device 7. High-speed and reliable inspection can be performed.

  Next, image processing and calculation processing and comparison determination processing performed by the control device 7 will be described. First, a solder area on which cream solder H is printed is extracted using image data obtained in the first imaging. That is, the control device 7 binarizes the luminance data among the image data with a predetermined threshold value. As described above, in the image data obtained by the first imaging, the solder area is bright and the other areas are dark. For this reason, by recognizing the bright area as the solder area, the non-solder area which is the printed board K surface as the non-measurement target portion on which the solder area and the cream solder H are not printed is extracted. .

  In the extracted non-solder area, a portion for measuring the reference height is selected by the control device 7. The non-solder area is the printed board K surface and is flat, and can be easily measured with a laser pointer.

  Next, the control device 7 calculates the height in the solder region using the image data of the three screens obtained in the second imaging. Regarding the light pattern projected on the cream solder H, a phase shift occurs due to the difference in height. Therefore, the control device 7 calculates the height of the reflecting surface based on the principle of the phase shift method (the fringe scanning method) based on the image data in each wavelength region where the phase of the light pattern is shifted by a predetermined pitch. .

  That is, the brightness of the point P on each screen can be expressed by an equation representing a sine wave. When the relative phase relationships of red, green, and blue are α, 0, and β (where α ≠ 0, β ≠ 0, α ≠ β), respectively, and the amplitudes and offset components of each equation are aligned as in this embodiment The brightness V0, V1, V2 of the point P on each screen is given by the following equations.

V0 = Asin (θ + α) + B (2a)
V1 = Asin θ + B (2b)
V2 = Asin (θ + β) + B (2c)
However, θ: position information for deriving the height, A: amplitude, B: offset component.

  From these formulas (2a) to (2c), the following formula (2d) is derived.

ここで、本実施の形態では、位相のずれがπ／２ずつであるため、α＝π／２，β＝−π／２とおける。すると、上記式（２ｄ）より下記式が（２ｅ）が導き出される。

In this embodiment, since the phase shift is π / 2, α = π / 2 and β = −π / 2. Then, the following equation (2e) is derived from the above equation (2d).

tan θ = (2V1−V0−V2) / (V0−V2) (2e)
From the formula (2e), the following formula (2g) is derived.

θ = arctan {(2V1-V0-V2) / (V0-V2)} (2g)
Using the position information θ calculated in this way, the height Z of the point P in the solder region is obtained based on the following equation.

  Here, when the angle formed by the vertical line of the illumination device 3 and the irradiation light beam when irradiated from the illumination device 3 toward the point P is ε, the angle ε is expressed by the following equation (3).

ε = f (θ + 2nπ) (3)
The height Z is derived according to the following formula (4).

Z = Lp−Lpc / tanε + Xp / tanε (4)
(However, Lp: Height from the reference plane of the illumination device 3, Lpc: Distance in the X-axis direction between the CCD camera 4 and the illumination device 3, and Xp: X coordinate of the point P.)
The height data of the point P obtained in this way is calculated for each pixel P of the imaging screen and stored in the memory of the control device 7. Further, the amount of the printed cream solder H is calculated by integrating the height of each part in the solder region based on the data of each part. And the data such as the position, area, height or amount of cream solder H obtained in this way is compared with reference data stored in advance, and whether or not this comparison result is within an allowable range, The quality of the printed state of the cream solder H in the inspection area is determined.

  As described above in detail, according to the present embodiment, based on the image data based on the first imaging by the CCD camera 4 and the three types of image data based on the second imaging under different relative phase relationships, The height of the cream solder H was calculated. Therefore, unlike the prior art in which it is necessary to perform imaging every time the relative phase relationship is changed, it is possible to perform imaging for each light component under different relative phase relationships. For this reason, it is only necessary to perform two irradiations and two imagings with respect to one point, and the time required for irradiation and imaging is significantly reduced. As a result, the time required for measurement is drastically reduced. be able to. In addition, when the light component pattern having a predetermined wavelength component is irradiated, the reflectance may vary greatly depending on the color of the measurement object, but even in such a case, the influence of the reflectance is caused by the second imaging. It will be offset. As a result, measurement accuracy can be improved.

  In addition, since the height of the cream solder H can be obtained based on three types of image data, the total number of data is less than that of the conventional technique that is calculated based on four times of imaging data. As a result, the calculation time can be significantly shortened. As a result, the time required for measurement can be dramatically reduced.

  In particular, in the present embodiment, the position information θ can be obtained based on mathematical expressions that are not so complicated, and the height can be calculated based on the position information θ. For this reason, the above-described effects can be reliably achieved without causing a delay due to complicated computation.

  Furthermore, in the above example, the illuminating device 3 includes a filter checker plate mechanism that can synthesize and irradiate light component patterns having different relative phase relationships using the filter checker plates 14 to 16. For this reason, since the liquid crystal is not required, the configuration can be simplified.

  In addition, the brightness of the reflected light when the white light illumination L is applied to the printed board K on which the cream solder H is printed obliquely from above is different between the solder area and the non-solder area. Therefore, regardless of the color of the surface of the cream solder H or the printed circuit board K, the solder area and the non-solder area can be extracted by an easy process that only compares the brightness of the image data. For this reason, in the calculation, it is not necessary to perform a correction calculation in consideration of the non-solder area. As a result, it is possible to simplify calculations, increase the size of equipment for correction, prevent complications, and the like.

  Further, the height calculation from the image data by the second imaging is performed only for the solder region. In the solder area, there is a single color and there is almost no color difference for each product. For this reason, in the three reflected lights of red, blue, and yellow, it is possible to prevent a situation in which appropriate luminance cannot be obtained, the balance is lost, and the height cannot be calculated.

  In addition, you may implement as follows, for example, without being limited to the content of description of embodiment mentioned above.

  (A) In the above embodiment, the lighting device 7 includes the red, green, and blue filter checkered strips 14, 15, and 16. However, as shown in FIG. By printing (or painting) stripes of a certain width on the board in the order of red R, yellow Y, cyan C, blue B, red R, yellow Y, cyan C, blue B,. It may be configured. The degree of color of each stripe is uniform without changing in a sine wave shape.

  Specifically, for each stripe, a pigment that transmits only a specific wavelength and shields other wavelengths is used. That is, as shown in FIG. 5, red R transmits only the wavelength of the red component. Yellow Y transmits only the yellow component, that is, the wavelengths of the red and green components. Cyan C transmits only the cyan component, that is, the wavelengths of the green and blue components. Blue B transmits only the wavelength of the blue component. At this time, it is preferable that the wavelength ranges of the red, green, and blue components that transmit light substantially coincide with the wavelength ranges of the CCD camera 4 that have high sensitivity for red, green, and blue, respectively.

  Since the arrangement of the stripe colors is in the order of red R, yellow Y, cyan C, and blue B, the portion that transmits light and the portion that blocks light for each wavelength of red, green, and blue components has a predetermined interval. Is repeated. For this reason, when the light transmitted through the checkered plate 30 is projected onto the irradiation area, the luminance of each wavelength in the irradiation area becomes substantially sinusoidal as shown in FIG. The relative phase relationships of red, green, and blue are −π / 2, 0, and π / 2, respectively. Therefore, by applying the checkered plate 30, it is possible to irradiate a light pattern for calculating the height.

  Note that the number of colors used for the checkered plate 30 may be four or more, for example, eight, ten, or sixteen colors.

  In addition, red, green, and blue printing (or painting) may be performed on one checkered plate, and the phases of the respective colors may be shifted from each other by a predetermined pitch during the printing (or painting). In the above case, the degree of each color may not necessarily be a sine wave but may be a rectangular wave.

  Further, the checkerboard may be configured by printing stripes having a constant width in the order of red, green, and blue. In this case, the luminance for each wavelength in the irradiation area is substantially a sine wave, and the relative phase relationships of red, green, and blue are −2π / 3, 0, and 2π / 3, respectively.

  (B) In the above embodiment, the solder area and the non-solder area are extracted based on the brightness of the reflected light when the white light illumination L is irradiated obliquely from above, but the reflection when the white light is irradiated from above. Color imaging of light may be used to distinguish between the solder area and the non-solder area based on the color difference between the cream solder H and the printed board K.

  (C) The height measurement of the reference plane is not limited to the measurement by the laser pointer, and a separate measuring device or the like may be used. Further, the height measurement of the reference plane is performed by using the phase shift method for the image regions of the three light component patterns obtained by the second imaging unit corresponding to the non-measurement object region extracted by the first imaging unit. The reference surface height may be measured by In this case, when the difference in reflectance for each color becomes a problem, it may be calculated by adding some correction means. For example, a half mirror may be installed on the same axis as the illumination device 3 and the height calculation may be performed by adding new three screen image data obtained by irradiating separate white light. Further, the height of the reference plane is measured by using the image of at least one light component pattern obtained by the second imaging unit corresponding to the non-measurement object region extracted by the first imaging unit, and the principle of triangulation The reference plane measurement may be performed by converting the position change of the light component pattern into height data based on the above.

  (D) Each light component pattern in the above embodiment does not necessarily need to be strictly distinguished into red, blue, and green. In short, it is intended that the wavelength ranges are different, and may be a light component pattern having an intermediate color such as yellow (RG) or cyan (blue green).

  (E) Further, the light component pattern may be four components instead of three components, and the image data of four screens may be obtained by the second imaging. May be calculated.

  (F) In the above-described embodiment, the present invention is embodied when measuring the height or the like of the cream solder H printed on the printed circuit board K. However, other than the solder solder printed on the IC package (for example, the lead) It can also be embodied when measuring height or the like. Furthermore, you may actualize when measuring the height etc. of another measuring object. Examples of other measurement objects include a printed material printed on a substrate, a laminate, and the like.

  (G) In addition, the above embodiment can be used as an apparatus for inspecting solder bumps, and the present invention can be embodied when the shape and volume of solder bumps are calculated from the contour and height of the extracted solder area and inspected. In this case, even if the solder bump has a spherical shape, it can be inspected satisfactorily.

  (H) When manufacturing the checkered strips 14, 15, 16 and (a) of the above embodiment, printing or painting may be applied, or an inorganic filter represented by a dichroic filter is striped. You may affix in the shape and may irradiate the light pattern of multiple wavelengths to a photosensitive film.

  (I) In the above embodiment, white light is emitted from the white light illumination L as the region extraction light. On the other hand, the light is not particularly limited to white light, and may be any one of red, blue, green, cyan, yellow, and the like.

  (J) In the above embodiment, the printing state inspection device 1 includes the white light illumination L and the illumination device 3, but omits the white light illumination L and replaces the illumination device 3 with red, green, and blue. A light component pattern having different phases and an illumination device capable of irradiating ultraviolet rays may be provided. That is, the illumination device includes a light source, a condenser lens, an irradiation lens, and a filter checkered plate. In addition to red, green, and blue wavelengths (white light), the light source can simultaneously emit ultraviolet light. Further, the filter lattice stripe plate shields light (transmits light) in a striped manner for each of red, green, and blue wavelengths, and allows total transmission of ultraviolet rays. In this case, instead of the CCD camera 4, a CCD camera that can simultaneously pick up images of red, green, and blue wavelength ranges and ultraviolet rays and obtain separated image data for each wavelength range is employed.

  With such a configuration, four image data can be obtained by performing only one imaging. Of these four image data, the ultraviolet image data can be used for extracting the region of the measurement object, and the three image data in the respective wavelength regions of red, green, and blue can be used for calculating the height.

  As a result, since it is not necessary to provide the white light illumination L, it is possible to provide a small and low cost printing state inspection apparatus. In addition, since imaging may be performed only once, the processing speed can be increased.

  In addition, it is not necessarily limited to ultraviolet rays, and any wavelength region other than white light may be used. For example, infrared rays may be used.

It is a schematic perspective view which shows typically the printing state inspection apparatus which comprises the three-dimensional measuring apparatus in one embodiment. It is a schematic block diagram which shows typically the structure of the more detailed three-dimensional measuring apparatus in one Embodiment. It is a graph which shows an example of the light intensity distribution of each filter of red, green, and blue from which relative phase relationship differs. It is a top view which shows typically the lattice fringe in another embodiment. (A) is a graph which shows the relationship of the transmittance | permeability and wavelength in each color of the lattice strip in another form, (b) is a graph which shows the relationship between the sensitivity of a camera and wavelength in another form. It is a graph which shows the brightness | luminance for each wavelength in the irradiation area where the transmitted light of the lattice strip was projected.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Print condition inspection apparatus, 3 ... Illumination device as illumination means, 4 ... CCD camera as imaging means, 7 ... Control apparatus which comprises calculation means, 11 ... Light source, 14 ... Red filter checkered board, 15 ... Green filter Plaid plate, 16 ... Blue filter plaid plate, L ... White light illumination, H ... Cream solder as measurement object, K ... Printed circuit board.

Claims (6)

A filter grid stripe plate used in a three-dimensional measuring apparatus, which is composed of a single plate-like body, shields light from a light source in a stripe shape for a predetermined wavelength component and allows light transmission for the remaining wavelength components. , At least three light component patterns having different relative phase relationships can be transmitted simultaneously,
For the first, second, and third wavelength components having different wavelength components from each other, a first region that transmits only the first wavelength component and a second region that transmits only the first and second wavelength components It is a configuration in which a region, a third region that transmits only the second and third wavelength components, and a fourth region that transmits only the third wavelength component are sequentially arranged in a stripe pattern. Filter plaid board. 2. The filter checkered plate according to claim 1 , wherein the first area is colored red, the second area is yellow, the third area is cyan, and the fourth area is blue. 3. . Three-dimensional measuring device, characterized in that it comprises a filter plaid plate according to claim 1 or 2. A three-dimensional measuring apparatus comprising the filter checkered board according to claim 1 or 2 , further comprising a determination unit that determines whether the printed state is good or not from a cream solder area and height printed on a printed circuit board. . A filter plaid plate according to claim 1 or 2, regions of solder bumps provided on the printed circuit board, three-dimensional measuring apparatus characterized by comprising determination means for determining acceptability of the shape of the solder bump from a height . Illumination means, characterized in that it comprises a filter plaid plate according to claim 1 or 2.

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