JP2002107125A - Measurement apparatus for three-dimensions - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a three dimension measurement apparatus whose measurement accuracy can be markedly improved, when a three-dimensional shape of a measurement object is to be measured, with the use of a phase shift method. SOLUTION: A printing state-inspecting apparatus 1 includes a table 2 for loading thereon a printed board K with a solder paste printed, an illumination device 3 for irradiating a plurality of sine wave-shaped light patterns, changing in phase from slantwise above to a surface of the printed board K, and a CCD camera 4 for imaging a reflecting light from the printed board K for each wavelength component. The CCD camera 4 separates the reflecting light for each light component and images at a time. A controller 7 calculates a the height of the solder paste by the phase shift method, based on imaging data. At this time, optimum wavelength component is selected, and data in the selected wavelength region are selected as optimum imaging data. The calculation is carried out on the basis of the imaging data, and as a result, effects due to color tone, etc., can thus be restricted to a minimum.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional measuring apparatus for measuring a three-dimensional shape of a measurement object using a phase shift method.

[0002]

2. Description of the Related Art Generally, when electronic components are mounted on a printed circuit board, cream solder is first printed on a predetermined electrode pattern provided on the printed circuit board. Next, the electronic components are 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 printing state of cream solder before it is led to a reflow furnace, and a three-dimensional measuring device may be 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. 11-21443). Gazette, Patent No. 27110
No. 42 etc.).

[0004] In the three-dimensional measuring device in the above technique, a CCD camera is used. That is, a light pattern having a stripe-like light intensity distribution is irradiated onto a measurement object (in this case, a printed circuit board) by an irradiation means including a combination of a light source and a filter having a sine wave pattern. Then, a point on the substrate is observed using a CCD camera arranged directly above. 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: contrast of sine wave (reflectance), φ: phase given by unevenness of object] At this time, the light pattern is moved. Phase by four steps (φ
+0, φ + π / 2, φ + π, φ + 3π / 2), and corresponding light intensity (luminance) distributions I0, I1,
An image having I2 and I3 is fetched, and position information θ is obtained based on the following equation.

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

[0007]

By the way, the color tone of the surface of the object (cream solder in the above example) and the like may differ due to the difference of the object to be measured or the difference of the measurement site of the object. In the three-dimensional measuring device,
The difference in color tone or the like greatly affects the light intensity (luminance) when reflected and captured as an image. Therefore, when the reflectance is low and the luminance difference is low,
The obtained position information θ contains a large amount of error, which may cause a decrease in measurement accuracy.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has been made in consideration of a tertiary shape capable of dramatically improving measurement accuracy when measuring a three-dimensional shape of a measurement object using a phase shift method. One of the main purposes is to provide an original measurement device.

[0009]

Means for Solving the Problems and Effects There will be described below characteristic means for achieving the above object. Also,
For each means, characteristic actions and effects will be described as necessary.

Means 1. Irradiating means capable of irradiating a light pattern having a plurality of wavelength components different from each other and having a stripe-like light intensity distribution to at least the measurement object, and reflected light from the measurement object irradiated with the light pattern Imaging means capable of acquiring image data by separating and imaging each wavelength component, a phase changing means for changing a relative phase relationship between the measurement object and the light pattern, and changing the phase by the phase changing means. Calculating means for calculating at least a predetermined height of the measurement object by a phase shift method based on a plurality of types of image data acquired by the imaging means under the plurality of relative phase relationships obtained. An original measuring device, wherein the calculating means calculates the predetermined height based on image data corresponding to an optimal wavelength component among the plurality of wavelength components. Three-dimensional measuring apparatus according to claim.

According to the means 1, at least the object to be measured is irradiated by the irradiation means with a light pattern containing a plurality of wavelength components different from each other and having a stripe-like light intensity distribution. In addition, the reflected light from the measurement object irradiated with the light pattern is separated and imaged by the imaging means for each wavelength component to obtain image data. At the time of the irradiation, a relative phase relationship between the measurement object and the light pattern is changed by a phase changing unit. And
Under the plurality of relative phase relationships changed by the phase changing unit, based on the plurality of types of image data acquired by the imaging unit, the calculating unit sets at least a predetermined height of the measurement target by the phase shift method. Is calculated. At this time, the color tone or the like of the surface of the object may be different due to the difference between the measurement objects or the measurement site of the object, and the reflected light may be affected by the difference in the color tone or the like. On the other hand, the calculating means in the means 1 calculates the predetermined height based on image data corresponding to an optimum wavelength component among the plurality of wavelength components. For this reason, the influence of the color tone and the like can be minimized, and the measurement accuracy can be dramatically improved with respect to the height calculated as a result.

Means 2. Irradiating means capable of irradiating a light pattern having a plurality of wavelength components different from each other and having a stripe-like light intensity distribution to at least the measurement target, and a relative phase relationship between the measurement target and the light pattern And a plurality of different relative phase relationships changed by the phase changing means, and the reflected light from the irradiation object irradiated with the light pattern is separated and imaged for each wavelength component. An imaging unit that can acquire image data corresponding to each wavelength component; an adoption unit that adopts an optimal wavelength component based on a plurality of types of image data acquired by the imaging unit; and the optimal wavelength component. Calculating means for calculating at least a predetermined height of the measurement object by a phase shift method based on a plurality of types of image data corresponding to the three-dimensional measurement apparatus. .

According to the means 2, at least the object to be measured is irradiated by the irradiation means with a light pattern including a plurality of wavelength components different from each other and having a stripe-like light intensity distribution. Further, the relative phase relationship between the measurement object and the light pattern is changed by the phase changing means. Then, under a plurality of relative phase relationships changed by the phase changing means, reflected light from the measurement object irradiated with the light pattern is separated and imaged for each wavelength component by the imaging means, and each wavelength is imaged. Image data corresponding to the component is obtained. Based on the plurality of types of image data acquired by the imaging unit, the selection unit selects an optimal wavelength component. Then, based on a plurality of types of image data corresponding to the optimal wavelength components, the calculating means calculates at least a predetermined height of the measurement object by the phase shift method. Therefore, the influence of the color tone and the like can be minimized, and the accuracy of the height calculated as a result can be dramatically improved.

Means 3. 3. The three-dimensional measurement apparatus according to claim 2, wherein the adopting unit adopts a wavelength component having the largest difference in luminance with respect to the phase to be changed as an optimal wavelength component.

According to the means 3, the selecting means selects the wavelength component having the largest difference in luminance with respect to the phase to be changed as the optimum wavelength component. Here, the luminance is easily affected by the color tone or the like, but the adopted wavelength component has the largest difference in the luminance with respect to the phase. Therefore, the height calculated as a result is most affected by the color tone or the like. It is based on difficult imaging data. As a result, it is possible to minimize the influence of the color tone and the like, and to achieve the above-mentioned operation and effect that the accuracy calculated with respect to the height calculated as a result can be dramatically improved. Become.

Means 4. The three-dimensional measuring apparatus according to claim 2 or 3, wherein the adopting unit adopts a wavelength component that minimizes an error in calculation as an optimal wavelength component.

According to the means 4, since the wavelength component that minimizes the error in the calculation is adopted as the optimum wavelength component, the error due to the influence of the color tone and the like can be minimized, and the accuracy can be improved. The above-described operation and effect can be more reliably achieved.

Means 5. The three-dimensional measurement apparatus according to any one of claims 1 to 4, wherein the phase changing unit changes a phase of a light pattern irradiated on the measurement target by the irradiation unit.

According to the means (5), the phase of the light pattern irradiated on the object to be measured by the irradiation means is changed by the phase changing means. For this reason, there is no need to move the measurement target or the like, and measurement can be performed with a relatively simple configuration without increasing the installation space. In this case, the phase changing means may be provided with "a structure capable of scanning a light pattern in a predetermined direction using a liquid crystal optical shutter using a liquid crystal element as a substantial lattice".

Means 6 The phase changing unit may change the phase by moving the measurement object or the irradiation unit and the imaging unit relative to the irradiation unit and the imaging unit or the measurement object. The three-dimensional measuring apparatus according to any one of the first to fourth aspects.

According to the means 6, the object to be measured or
The phase is changed by moving the irradiation unit and the imaging unit relative to each other. For this reason, it is sufficient to use a mechanical moving device, and the structure does not become complicated.

Means 7. The three-dimensional measuring apparatus according to any one of means 1 to 6, wherein the irradiation unit is capable of irradiating white light.

According to the means 7, since the light of all wavelength components is irradiated as white light by the irradiating means, the above operation and effect are surely achieved. In addition, the structure of the irradiation unit can be simplified and the cost can be reduced.

Means 8. Any one of the means 1 to 6, wherein the irradiating means can simultaneously irradiate a light pattern composed of at least two light component patterns of mutually different wavelength components, and the periods of the respective light component patterns are equal to each other. A three-dimensional measuring device according to any of the above.

According to the means 8, since the irradiation means simultaneously irradiates the light patterns composed of at least two light component patterns of mutually different wavelength components, an optimum light component pattern can be set in advance to optimize the light pattern. Wavelength components can be easily adopted. However, the periods of the respective light component patterns need to be equal to each other.

Means 9 The different wavelength components are red and green, red and blue, red and infrared, green and blue, green and infrared, blue and infrared, red, green and blue, red, green and infrared, red, blue and infrared, green The three-dimensional measurement apparatus according to any one of means 1 to 8, wherein the three-dimensional measurement device has wavelength components of blue, infrared, and red, blue, green, and infrared.

According to the means 9, the wavelength ranges do not easily overlap, and an extremely special imaging means is not required, so that an increase in cost can be suppressed.

Means 10. The three-dimensional measurement apparatus according to any one of means 1 to 9, wherein the plurality of relative phase relationships are at least three. in this case,
Instead of "at least three ways", "three ways"
“Four ways” or “three or four ways” may be used.

According to the means 10, when the predetermined height is calculated on the basis of the three types of image data, the total number of times of imaging can be reduced, and the imaging time can be shortened. As a result, the time required for measurement can be significantly reduced. Further, when a predetermined height is calculated based on four types of image data, the calculation is simplified and the calculation time can be reduced.

Means 11 The three-dimensional measuring device according to any one of means 1 to 10, wherein the stripe shape is a substantially sine wave shape.

According to the means 11, since the light pattern has a substantially sinusoidal light intensity distribution, the measurement accuracy can be further improved.

Means 12. The three-dimensional measuring device according to any one of means 1 to 11, which measures at least the height of cream solder printed and formed on a printed circuit board or an IC package, and derives a pass / fail judgment based on the measured value. Possible cream solder printing inspection device.

According to the means 12, a printed circuit board or an IC
At least the height of the cream solder printed on the package is measured, and a pass / fail judgment is made based on the measured value. For this reason, each of the above-described effects can be obtained when measuring the cream solder, and the quality can be determined with high accuracy.

Means 13. A step of printing and forming cream solder on a printed circuit board or an IC package;
2. A substrate, comprising: an inspection step of performing quality judgment using the cream solder printing inspection device according to 2; and a reflow step of performing reflow so as to mount only those judged as non-defective in the inspection step. Manufacturing method.

According to the means 13, since the quality judgment is made accurately, it is possible to suppress the occurrence of defective products with respect to the obtained substrate.

[0036]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram schematically showing a printing state inspection apparatus 1 including the three-dimensional measuring apparatus according to the present embodiment. As shown in FIG.
Is a table 2 on which a printed board K on which cream solder is printed is placed, and an illuminating device 3 which constitutes an irradiating means for irradiating a predetermined light component pattern obliquely from above on the surface of the printed board K. And a CCD camera 4 which constitutes imaging means for imaging the irradiated portion on the printed board K. The cream solder in the present embodiment is formed by printing on an electrode pattern made of copper foil provided on a 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 mounted on the table 2 to move in arbitrary directions (X-axis direction and Y-axis direction). It can be made to slide.

From the lighting device 3 in the present embodiment,
A light pattern of white light is applied. More specifically, as shown in FIG. 2, the illuminating device 3 includes a phase changing mechanism 11 as a phase changing means including a known liquid crystal optical shutter. Irradiating a changing light pattern. Therefore, the light from the light source is irradiated onto the printed circuit board K via the phase changing mechanism 11, and in particular, the printed circuit board K is subjected to a striped light pattern (sine wave) in which the illuminance changes in a sinusoidal manner. pattern)
Is irradiated.

In the illumination device 3, light from a light source (not shown) is guided by an optical fiber to a pair of condenser lenses, where it is converted into parallel light. The parallel light is guided via a liquid crystal element to a projection lens arranged in the constant temperature control device. Then, four light patterns that change in phase are emitted from the projection lens. As described above, by using the liquid crystal optical shutter in the illumination device 3, when a stripe-shaped light pattern is created, a light whose illuminance is close to an ideal sine wave can be obtained. The measurement resolution of measurement is improved. Further, the control of the phase shift of the light pattern can be performed electrically, and the control system can be made compact.

The CCD camera (color CCD camera) 4 includes first to third dichroic mirrors 21,
22, 23 and first to third imaging units 2 corresponding thereto
4, 25, 26 are provided. That is, the first dichroic mirror 21 reflects light within a predetermined wavelength range (corresponding to red light) (transmits light of other wavelengths), and
Captures the reflected light. The second dichroic mirror 22 reflects light in a predetermined wavelength range (corresponding to green light) (transmits light of other wavelengths), and the second imaging unit 25 captures the reflected light. In addition, the third
(A normal mirror may be used) 23 reflects light in a predetermined wavelength range (corresponding to blue light) (transmits light of other wavelengths), and outputs the third imaging unit 26.
Captures the reflected light.

In the present embodiment, as shown in FIGS. 1 and 2, the CCD camera 4, the lighting device 3, the motor 5,
A control device 7 for controlling the driving of the control unit 6 and executing various calculations based on the image data captured by the CCD camera 4 is provided. That is, when the printed board K is placed on the table 2, the control device 7 first controls the driving of the motors 5 and 6 to move it to a predetermined position, and moves the printed 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. In addition, the control device 7 controls the driving of the illumination device 3 to start irradiation of the light pattern, and shifts the phase of the light pattern by a predetermined pitch (for example, “π / 2” in the present embodiment) by 4 °. The type of irradiation is sequentially controlled. Further, while the irradiation in which the phase of the light pattern is shifted is performed in this manner, the control device 7
The driving of the D camera 4 is controlled to take an image of the inspection area portion for each of these irradiations and for each color.
Image data for three screens is obtained. That is, image data is obtained for each of the four phase shifts and for each of the three wavelength ranges of R (red), G (green), and B (blue).

Here, the configuration of the control device 7 will be described more specifically with reference to the block diagram of FIG. Control device 7
Includes a selector 31 that outputs a signal for switching a phase to the phase changing mechanism 11. Further, the control device 7 includes an image memory 32, and sequentially stores the image data of the four stages for each color (R, G, B). That is, the image memory 32 includes the first image memory 33 and the second image memory 3 corresponding to each of red, green, and blue.
4, a third image memory 35 and a fourth image memory 36. In the following, for the sake of convenience, for example, the first image memory of red is described as the first image memory (R) 33 or the like.

Further, corresponding to the respective image memories 33 to 36, first to fourth connection terminals 37, 38, 39,
40 and first to fourth switching elements 41, 42, 4
3, 44 are provided. The switching of the switching elements 41 to 44 is controlled by the selector 31 in accordance with the above-described phase switching. That is, when the phase is set to “0” by the selector 31, only the first switching element 41 is turned on, and the others are turned off. Therefore, in this case, the image data from the CCD camera 4 is stored in the first image memory 33.

Further, the phase is set to "π /
When “2” is set, only the second switching element 42 is turned on, and the others are turned off. Therefore,
In this case, the image data from the CCD camera 4 is stored in the second image memory 34. Similarly, selector 31
When the phase is set to “π”, only the third switching element 43 is turned on. In this case, C
The image data from the CD camera 4 is stored in a third image memory 35.
Is stored in At the same time, the phase is set to “3” by the selector 31.
π / 2 ”, the fourth switching element 4
Only 4 is turned on, and in this case, the image data from the CCD camera 4 is stored in the fourth image memory 36.

The control device 7 performs various image processing (calculation) based on the image data stored as described above. That is, the control device 7 stores in the first to fourth image memories 33 to 36 including a calculation unit 48 including a contrast calculation unit 45 as a selection unit, a position information calculation unit 46, and a height calculation unit 47. All the obtained image data are temporarily transmitted to the contrast calculator 45. Also, corresponding to the position information calculation unit 46, the first to fourth data input terminals 51, 52, 53, 54 and the first to fourth data input switching elements 55, 56 are provided for each of the image memories 33 to 36. , 57, 58 are provided. Then, the contrast calculator 45
The data input switching elements 55 to 58 are calculated by the contrast calculation unit 45 based on the calculation results of
Switching control is performed. In other words, when the contrast calculator 45 determines that the red data should be adopted this time, the first to fourth data input switching elements 55 to 58 are all red image memories (R) 33 to 36. Are connected only, and the others are not connected. Therefore, in this case, the four red image data are transmitted to the position information calculation unit 46. If the contrast calculator 45 determines that green data should be adopted this time, the first to fourth data input switching elements 55 to 58 are all green image memories (G) 33 to 36. Are connected only, and the others are not connected. Therefore, in this case, the four green image data are transmitted to the position information calculation unit 46. Similarly, when the contrast calculation unit 45 determines that blue data should be adopted this time, the first to fourth data input switching elements 55 to 55 are used.
58 are connected only to the blue image memories (B) 33 to 36, and the others are not connected. Therefore, in this case, the four blue image data are transmitted to the position information calculation unit 46.

Then, based on the position information θ calculated by the position information calculation section 46, the height calculation section 47
The height is calculated for each pixel (inspection area). The calculated height data is transmitted to the height data storage memory 59. In addition, the control device 7 includes a determination unit 60, and the determination unit 60 performs a determination based on the height data stored in the height data storage memory 59.
The quality of the printed cream solder is determined.

While the above-described image processing is being performed, the controller 7 controls the motors 5 and 6 as appropriate to move the table 2 to the next inspection area. The control device 7 also stores the image data in the image memory 32. On the other hand, once the image processing is completed, the next image data is already stored in the image memory 32, so that the control device 7 can immediately perform the next image processing. That is, the inspection is performed on the other hand while the next inspection area (m +
(1) and image input, and on the other hand, m-th image processing and comparison judgment. Thereafter, the same parallel processing is repeated alternately until the inspection in all the inspection areas is completed. As described above, in the printing state inspection apparatus 1 according to the present embodiment, by sequentially performing image processing while moving the inspection area under the control of the control device 7, the printing state of the cream solder on the printed circuit board K can be increased at a high speed. In addition, the inspection can be performed reliably.

Next, the contents of processing performed by the control device 7 will be described focusing on image processing and arithmetic processing. That is, FIG. 3 is a flowchart showing a “height calculation routine” executed when the height of the cream solder is calculated by the control device 7 (mainly the calculation means 48). As shown in the drawing, the control device 7 first performs a phase shift measurement in step S101. That is, with respect to the light pattern projected on the printed board K, a phase shift occurs between the surface of the printed board K and the cream solder based on the difference in height. Therefore, the control device 7
First, image data (image data of four screens in the present embodiment) in each wavelength region (R, G, B) in which the phase of the light pattern is shifted by a predetermined pitch is obtained.

More specifically, the selector 31 of the control device 7
Are the switching elements 41 to 44 and the phase change mechanism 1
1 are sequentially switched. As described above, the selector 31
When the phase is set to “0”, only the first switching element 41 is turned on. In this case, C
The image data from the first to third imaging units 24 to 26 of the CD camera 4 are stored in the first image memory (R, G, B) 33 for each wavelength range as zero-phase image data. When the selector 31 sets the phase to “π / 2”, only the second switching element 42 is turned on. In this case, the first to third switching elements of the CCD camera 4 are turned on.
Image data from the imaging units 24 to 26 of the second image memory (R, R,
G, B) 34. Similarly, when the phase is set to "π" by the selector 31, only the third switching element 43 is turned on.
Image data from the first to third imaging units 24 to 26 of the camera 4 are stored in the third image memory (R, G, B) 35 for each wavelength range as image data of phase π. Further, when the phase is set to "3π / 2" by the selector 31, only the fourth switching element 44 is turned on. In this case, the first to third imaging units 24 to 26 of the CCD camera 4 are used. Is stored in the fourth image memory (R, G,
B).

Here, in general, the light intensity at the point P on the screen when the phase is shifted by a predetermined pitch, for example, 0, π / 2, π, 3π / 2 as in the present embodiment.
V0, V1, V2, and V3 are given by the following equations.

V0 = Asinθ + B (1) V1 = Asin (θ + π / 2) + B (2) V2 = Asin (θ + π) + B (3) V3 = Asin (θ + 3π / 2) + B (4) where A: reflectance, B: offset component, θ: position information for deriving height.

The following equation (5) is derived from these equations (1) to (4).

Θ = ARCTAN {(V0−V2) / (V1−V3)} (5) From the above general formula, the light intensity (luminance) R0 (or G0 or B0) of each wavelength (each color tone) is obtained. ), R1 (or G1 or B1), R2
(Or G2 or B2) and R3 (or G3 or B3) are given by the following formulas.

R0 (or G0 or B0) = Asin θ + B (1R, 1G, 1B) R1 (or G1 or B1) = Asin (θ + π / 2) + B (2R, 2G, 2B) R2 (or G2 or B2) = Asin (θ + π) + B (3R, 3G, 3B) R3 (or G3 or B3) = Asin (θ + 3π / 2) + B (4R, 4G, 4B) Now, each of the image memories (R, G, B) Image data (light intensities R0 to R3, G0 to G3, B0 to B
3) is transmitted to the contrast calculation unit 45 once. Then, in the subsequent step S102, the contrast calculator 45 performs the R, G, B contrast calculation based on the transmitted image data. However, in the present embodiment, “contrast” refers to a difference in light intensity with respect to the changed phase.
Here, for convenience, the sum of the absolute value of the denominator and the absolute value of the numerator in each wavelength band in the above equation (5) is referred to.

Therefore, the contrast Rc of the red wavelength component
on, the contrast Gcon of the green wavelength component, and the contrast Bcon of the blue wavelength component are expressed by the following equations (6R, 6G,
6B).

Rcon = | R0-R2 | + | R1-R3 | (6R) Gcon = | G0-G2 | + | G1-G3 | (6G) Bcon = | B0-B2 | + | B1-B3 | (6B) Then, in step S103, the control device 7 (contrast calculation unit 45) checks the contrast Rco of each color component.
Among n, Gcon, and Bcon, the largest one is determined, and the data in the wavelength range of the largest color is adopted as the optimum data for calculating the position information θ. In this case, for example, when the contrast Rcon of the red component is the maximum, the contrast calculator 45 sets the first to fourth data input switching elements 55 to adopt the light intensity data of the red component for calculation. To 58 are all the first red components.
To the fourth image memories (R) 33 to 36. As a result, the image data (light intensity) stored in the first to fourth image memories (R) 33 to 36 for the red component
R0 to R3) are transmitted to the position information calculation unit 46.

Then, in the next step S104, the position information calculation section 46 calculates the position information θ in accordance with the above equation (5). For example, when the adopted data is of a red component, the position information θ is calculated based on the following equation (5R).

Θ = ARCTAN {(R0−R2) / (R1−R3)} (5R) Then, in step S105, using the position information θ calculated as described above, based on the following equation Then, the height Z of the point P on the printed board K (cream solder) is obtained.

Here, assuming that the angle between the vertical line of the lighting device 3 and the light beam emitted from the lighting device 3 toward the point P is ε, the angle ε is expressed by the following equation (7). Is done.

Ε = f (θ + 2nπ) (7) The height Z is derived according to the following equation (8).

Z = Lp−Lpc / tanε + Xp / tanε (8) (where Lp is the height of the lighting device 3 from the reference plane, Lp
c: distance between the CCD camera 4 and the illumination device 3 in the X-axis direction,
Xp: X coordinate of point P. The height data of the point P obtained in this way is calculated for each pixel of the imaging screen and stored in the height data storage memory 59 of the control device 7. Also,
In the next step S <b> 106, it is determined whether or not the height calculation has been performed for all the predetermined specified pixels. Then, when a negative determination is made, the process proceeds to step S102, and when an affirmative determination is made, the subsequent process is temporarily ended.

The determining means 60 detects the printing range of the cream solder which is higher than the reference plane based on the data of each pixel, and integrates the height of each part within this range, The amount of printed cream solder is calculated. Then, data such as the position, area, height or amount of the cream solder obtained in this manner is compared and determined with reference data stored in advance, and whether or not this comparison result is within an allowable range is determined. The quality of the printing condition of the cream solder in the inspection area is determined.

As described in detail above, according to the present embodiment, of the contrasts Rcon, Gcon, and Bcon of each color component,
The largest one is determined, and the data in the largest color (wavelength range) is adopted as the optimal data for calculating the position information θ. Here, the color tone of the surface of the object (cream solder) may differ due to the difference (type, shape, etc.) of the measurement object (cream solder) or the measurement site of the object (cream solder). Can affect the reflected light. On the other hand, in the present embodiment,
The height is calculated based on image data corresponding to the optimal wavelength component among the plurality of wavelength components of red, green, and blue. For this reason, the influence of the color tone and the like can be minimized, and the measurement accuracy can be dramatically improved with respect to the height calculated as a result. Therefore, the accuracy of the pass / fail judgment can be improved.

Incidentally, the present invention is not limited to the contents described in the above embodiment, but may be carried out, for example, as follows.

(A) The light component pattern in the above embodiment has a sinusoidal light intensity distribution. However, if the light component pattern is a stripe pattern, for example, a sawtooth or rectangular wave light intensity distribution is used. May be a light pattern having the following.

(B) Although not specifically mentioned in the above embodiment, a step of printing and forming cream solder on the printed board K and an inspection for judging acceptability using the printing state inspection apparatus 1 in the above embodiment. The present invention can also be embodied in a method for manufacturing a substrate including a process and a reflow process of performing a reflow process so as to mount only those judged as non-defective in the inspection process. According to the manufacturing method,
Since the time required for inspection can be shortened,
The overall manufacturing time can be reduced, and the occurrence of defective products can be suppressed.

(C) In the above embodiment, the case where the phase is shifted by π / 2 is mainly described, but other than this, the amount of phase to be shifted, for example, α =
(2/3) π, α = (1/3) π, α = (1/4) π,
Any shift amount among α = (1/8) π and α = (1/16) π can be adopted.

(D) In the above embodiment, the printed circuit board K
Although the present invention has been embodied when measuring the height and the like of cream solder printed on the IC package, the present invention can also be embodied when measuring the height and the like of cream solder printed on an IC package (for example, leads). . Further, the present invention may be embodied when measuring the height or the like of another measurement target. Examples of other measurement objects include a printed matter printed on a substrate, a laminate, and the like.

(E) Although red, green, and blue are mentioned as typical examples of the wavelength component in the above embodiment, the present invention is not necessarily limited to these. In addition, examples of wavelength components different from each other, in addition to the above examples, red and green, red and blue, red and infrared, green and blue, green and infrared, blue and infrared, red, green and infrared, red, Blue and infrared, green, blue and infrared, or red, blue, green and infrared wavelength components, and the like.
Further, it is not always necessary to strictly distinguish between red, green, blue, infrared and the like. In other words, the light component pattern may have a different wavelength range, and may be a light component pattern having an intermediate color such as yellow (RG) or cyan (blue-green).

(F) In the above-described embodiment, the phase change mechanism 11 is provided inside the lighting device 3 so that the light pattern can be shifted by this. A device capable of shifting the phase may be provided. Further, the printed board K (and thus cream solder) is illuminated by the lighting device 3 and the CCD camera 4.
The phase may be changed by relatively moving the phase. Conversely, the printed circuit board K may be fixed, and the illumination device 3 and the CCD camera 4 may be relatively moved.

(G) In the above embodiment, the phase is shifted by four steps to obtain image data having four different phases, and the position information θ is calculated according to the above equation (5).
On the other hand, the phase information may be shifted by three stages to obtain image data having three different phases and calculate the position information. In this case, the light intensity when the phase is shifted by π / 2, such as 0, π / 2, π, respectively, is
Taking the case of V0, V1, and V2 as a representative example, the following equation (5 ′) is derived as a general equation instead of the above equation (5).

Θ = ARCTAN [(2V0−V1−V2) / (V1−V2)] (5 ′) In this case, after selecting an optimal wavelength range, the above equation (5) The position information θ is calculated based on ').

(H) In the above embodiment, the CCD camera 4 is used as the imaging means. However, another imaging means (for example, an imaging means having a CMOS sensor) may be used.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view schematically showing a printing state inspection device including a three-dimensional measuring device according to an embodiment.

FIG. 2 is a block diagram for explaining an electrical configuration of a control device.

FIG. 3 is a flowchart illustrating a “height calculation routine” executed by the control device.

[Explanation of symbols]

1. Print condition inspection device equipped with three-dimensional measuring device 2.
Table, 3 ... Illumination device constituting irradiation means, 4 ... CCD camera as imaging means, 7 ... Control device, 11 ... Phase change mechanism constituting phase change means, 31 ... Selector, 3
2 ... image memory, 45 ... contrast calculation unit constituting adoption means, 46 ... position information calculation unit, 47 ... height calculation unit,
48 arithmetic means, 59 height memory, 60
Judging means, K: Printed circuit board.

Claims (11)

[Claims] 1. An irradiation unit that can irradiate at least a measurement target with a light pattern including a plurality of wavelength components different from each other and having a stripe-like light intensity distribution, and a measurement target irradiated with the light pattern. Imaging means capable of capturing the image data by separating the reflected light from the object for each wavelength component and acquiring image data; phase change means for changing a relative phase relationship between the object to be measured and the light pattern; Calculation means for calculating at least a predetermined height of the measurement object by a phase shift method based on a plurality of kinds of image data acquired by the imaging means under a plurality of kinds of relative phase relationships changed by the change means. A three-dimensional measuring device, wherein the calculating means calculates the predetermined height based on image data corresponding to an optimal wavelength component among the plurality of wavelength components. Three-dimensional measuring apparatus, characterized in that. 2. An irradiation means which can irradiate at least a measurement target with a light pattern including a plurality of wavelength components different from each other and having a stripe-like light intensity distribution, the measurement target, and the light pattern Phase change means for changing the relative phase relationship between the light pattern, under a plurality of types of relative phase relations changed by the phase change means, reflected light from the measurement object irradiated with the light pattern for each wavelength component The image is separated into
Imaging means capable of acquiring image data corresponding to each wavelength component; adoption means for adopting an optimal wavelength component based on a plurality of types of image data acquired by the imaging means; corresponding to the optimal wavelength component A three-dimensional measuring apparatus, comprising: a calculating means for calculating at least a predetermined height of the measurement object by a phase shift method based on the plurality of types of image data. 3. The three-dimensional measuring apparatus according to claim 2, wherein said selecting means selects a wavelength component having a largest difference in luminance with respect to a phase to be changed as an optimal wavelength component. . 4. The three-dimensional measuring apparatus according to claim 2, wherein said selecting means selects a wavelength component that minimizes an error in calculation as an optimal wavelength component. 5. The apparatus according to claim 1, wherein the phase changing means changes a phase of a light pattern irradiated on the measurement object by the irradiation means.
The three-dimensional measuring device according to any one of the above. 6. The method according to claim 1, wherein the phase changing unit is configured to:
5. The method according to claim 1, wherein a phase is changed by relatively moving the irradiation unit and the imaging unit with respect to the irradiation unit and the imaging unit or the measurement target. 6. 3. The three-dimensional measuring device according to 1. 7. The three-dimensional measuring apparatus according to claim 1, wherein said irradiating means is capable of irradiating white light. 8. The illuminating means is capable of simultaneously irradiating a light pattern composed of at least two light component patterns of mutually different wavelength components, and wherein the periods of the respective light component patterns are equal to each other. Items 1 to 6
The three-dimensional measuring device according to any one of the above. 9. The different wavelength components are red and green, red and blue, red and infrared, green and blue,
Green and infrared, blue and infrared, red, green and blue, red, green and infrared, red, blue and infrared, green, blue and infrared, or red, blue, green and infrared wavelength components The three-dimensional measuring device according to claim 1. 10. The three-dimensional measuring apparatus according to claim 1, wherein the plurality of relative phase relationships are at least three. 11. The three-dimensional measuring apparatus according to claim 1, wherein the stripe has a substantially sinusoidal shape.