阅读说明：本技术 三维测量装置以及三维测量方法 (Three-dimensional measuring device and three-dimensional measuring method ) 是由 新山孝幸 大山刚 坂井田宪彦 于 2020-04-07 设计创作，主要内容包括：提供能够实现测量精度的提高等的三维测量装置以及三维测量方法。基板检查装置(10)包括具有照射装置(13)、投影装置(14)以及相机(15)的测量头(12),首先,从照射装置(13)向印刷基板(1)上的检查范围照射狭缝光,测量该检查范围的高度。接着,基于该检查范围的高度求出该检查范围所包含的各焊膏的测量基准面的高度,并且确定在对焦状态下拍摄各焊膏的高度方向整个区域所需的需要对焦范围。接着,基于各焊膏的需要对焦范围和相机(15)的景深进行测量头(12)的高度位置和在该高度位置作为测量对象的焊膏的关联。然后,使测量头(12)相对于在此确定的规定的高度位置依次移动,对在该高度位置作为测量对象的焊膏(5)执行焊料测量。(Provided are a three-dimensional measurement device and a three-dimensional measurement method, which can improve measurement accuracy and the like. A substrate inspection device (10) includes a measurement head (12) having an irradiation device (13), a projection device (14), and a camera (15), and first, slit light is irradiated from the irradiation device (13) to an inspection area on a printed substrate (1), and the height of the inspection area is measured. Then, the height of the measurement reference surface of each solder paste included in the inspection range is obtained based on the height of the inspection range, and a required focusing range necessary for imaging the entire area of each solder paste in the height direction in a focused state is determined. Then, the height position of the measuring head (12) and the solder paste as the measuring object at the height position are correlated based on the required focusing range of each solder paste and the depth of field of the camera (15). Then, the measuring head (12) is sequentially moved with respect to a predetermined height position determined here, and solder measurement is performed on the solder paste (5) as a measurement object at the height position.)

1. A three-dimensional measurement apparatus for performing three-dimensional measurement by a predetermined three-dimensional measurement method on an object to be measured placed in a predetermined measurement target region of an object to be measured by aligning a predetermined measurement unit with the predetermined measurement target region,

the measurement unit includes:

a first irradiation unit capable of irradiating the measurement target region with predetermined light for height measurement of the measurement target region;

a second irradiation unit capable of irradiating the measurement target region with a predetermined pattern light for performing three-dimensional measurement of the measurement target; and

an imaging unit capable of imaging the region to be measured irradiated with the predetermined light or the predetermined pattern light,

the three-dimensional measuring device includes:

an area height acquisition unit that acquires height information of the region to be measured based on image data obtained by irradiating the predetermined light and being captured by the imaging unit;

a reference surface height acquisition unit that calculates height information of a measurement reference surface of each of the plurality of objects to be measured included in the region to be measured, based on height information of the region to be measured;

a focusing required range determining unit that determines focusing required ranges required to photograph the entire area of the measured object in the height direction in a focused state, based on the height information of the measurement reference surface, for the plurality of measured objects, respectively;

a correlation unit that performs correlation between a height position of the measurement unit and the measured object as a measurement object at the height position based on a focus required range of the plurality of measured objects and a depth of field of the photographing unit;

a height adjustment unit configured to be capable of moving the measurement unit in a height direction and sequentially positioning the measurement unit with respect to a predetermined height position determined by the association; and

and a three-dimensional measurement unit that is capable of performing three-dimensional measurement of the measurement target that is a measurement target at a predetermined height position at which the measurement unit is positioned, based on image data captured by the imaging unit under the predetermined pattern light irradiated from the second irradiation unit.

2. The three-dimensional measuring device of claim 1, comprising:

a number-of-times determination unit that determines whether the number of times of the three-dimensional measurement required in the measured region increases in a case where the three-dimensional measurement by the three-dimensional measurement unit is performed at an initial height position when the measurement unit is aligned to the measured region in a previous stage of the height adjustment by the height adjustment unit,

performing the first three-dimensional measurement by the three-dimensional measurement unit at the first height position without increasing the number of three-dimensional measurements.

3. The three-dimensional measuring device according to claim 1 or 2, comprising:

distance determination means for determining, when the height adjustment means performs height adjustment, which of a case where the measurement means moves to a height position that is the lowest among the plurality of height positions of the measurement means specified by the association and a case where the measurement means moves to a height position that is the highest, the distance to be moved from the first height position when the measurement means is aligned to the measurement target region is shorter,

the height adjusting means moves the measuring means from the first height position to the lower-most height position or the upper-most height position by a shorter movement distance.

4. The three-dimensional measuring device according to any one of claims 1 to 3,

the association unit associates the height position of the measurement unit with the object to be measured with respect to each of the plurality of objects to be measured, so that at least one depth of field exists in the entire range to be focused including the object to be measured.

5. A three-dimensional measurement method for performing three-dimensional measurement by a predetermined three-dimensional measurement method on a measurement target placed in a predetermined measurement target region of a predetermined measurement target by aligning a predetermined measurement unit having a predetermined irradiation unit and a predetermined imaging unit with the predetermined measurement target region, the method comprising:

a region height acquisition step of acquiring height information of the region to be measured based on image data obtained by irradiating the region to be measured with predetermined light and capturing the image;

a reference surface height acquisition step of calculating height information of a measurement reference surface of each of the plurality of objects to be measured included in the region to be measured based on the height information of the region to be measured;

a focusing required range determining step of determining, for each of the plurality of objects to be measured, a focusing required range required for photographing the entire area of the object to be measured in the height direction in a focused state based on the height information of the measurement reference surface;

a correlation step of performing correlation between a height position of the measurement unit and the measured object as a measurement object at the height position based on a focus required range of the plurality of measured objects and a depth of field of the photographing unit;

a height adjustment step of moving the measurement unit in a height direction and sequentially positioning the measurement unit with respect to a predetermined height position determined by the association;

and a three-dimensional measurement step of performing three-dimensional measurement of the measurement target at a predetermined height position at which the measurement unit is positioned, based on image data obtained by irradiating the measurement target region with a predetermined pattern light and capturing the image data.

6. The three-dimensional measurement method according to claim 5, comprising:

a number-of-times determination step of determining whether or not the number of times of the three-dimensional measurement required in the region to be measured increases in a case where the three-dimensional measurement is performed at an initial height position when the measurement unit is aligned to the region to be measured at a stage prior to the height adjustment step,

performing an initial three-dimensional measurement at the initial height position without increasing the number of three-dimensional measurements.

7. The three-dimensional measurement method according to claim 5 or 6, comprising:

a distance determination step of determining, when the height adjustment step is performed, which of a case where the measurement means is moved to a height position that is the lowest among the plurality of height positions of the measurement means determined by the association and a case where the measurement means is moved to a height position that is the highest, is shorter than a moving distance from the first height position when the measurement means is aligned to the measurement target region,

in the height adjusting step, the measuring means is moved from the first height position to the lowest height position or the highest height position by a shorter movement distance.

8. The three-dimensional measurement method according to any one of claims 5 to 7,

in the step of associating, in a first step,

the height position of the measuring unit and the object to be measured are associated with each other so that at least one depth of field exists in the entire focusing range including the object to be measured.

Technical Field

The present invention relates to a three-dimensional measuring apparatus and a three-dimensional measuring method for performing three-dimensional measurement of a printed board or the like.

Background

In general, when an electronic component is mounted on a printed circuit board, first, a solder paste is printed on a predetermined electrode pattern disposed on the printed circuit board. Next, the electronic component is temporarily fixed on the printed board based on the viscosity of the solder paste. Thereafter, the printed circuit board is guided to a reflow furnace and subjected to a predetermined reflow process to be soldered. Recently, it is necessary to inspect the printing state of the solder paste at a stage before the solder paste is led to the reflow furnace, and a three-dimensional measuring device is sometimes used at this inspection.

Conventionally, various three-dimensional measuring apparatuses have been proposed which project predetermined pattern light to perform three-dimensional measurement. Among them, a three-dimensional measuring apparatus using a phase shift method is known.

A three-dimensional measurement device using a phase shift method is provided with: a projection device that projects pattern light having a striped light intensity distribution (hereinafter referred to as a "stripe pattern") from obliquely above a predetermined inspection area on a printed circuit board; and an imaging device that images the projected inspection range of the stripe pattern.

With this configuration, the phases of the stripe patterns of a predetermined inspection area projected onto the printed circuit board are shifted for each of a plurality of sets (for example, 4 sets), and imaging is performed on each of the stripe patterns having different phases, thereby acquiring a plurality of sets of image data relating to the inspection area. Then, based on these plural image data, three-dimensional measurement of the inspection range is performed by the phase shift method.

However, when the printed circuit board is warped, it is difficult to partially capture the inspection range within the depth of field of the imaging device, and the measurement accuracy may be degraded because the image data that is not in focus is captured.

In recent years, the following techniques are also considered: before starting the measurement in the inspection range, the measurement head is moved in the height direction and adjusted so that the distance between the measurement head integrally including the projection device and the imaging device and the predetermined inspection range on the printed circuit board is within a predetermined range (see, for example, patent documents 1 and 2).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2004-198129;

patent document 2: japanese patent laid-open No. 2014-504721.

Disclosure of Invention

Conventionally, since the number of pixels of the imaging element is small, the field of view of the imaging device is narrow, and the height of the solder paste printed on the printed circuit board is only a low height for the arithmetic circuit, the height of the measuring head is adjusted 1 time before starting the measurement in a predetermined inspection range on the printed circuit board, and then the measurement can be completed for all the solder pastes in the one inspection range (the imaging field of view) without performing the height adjustment thereafter.

However, in recent years, the number of pixels of the imaging element has increased significantly, and if the same resolution is used, a wide range of imaging can be performed, and therefore, even within one inspection range, the imaging element is susceptible to warpage of the printed substrate and the like.

Further, due to the development of the half-etching technique of the metal mask for solder printing, the solder coating technique of the dispensing method, and the like, not only the solder paste having a low height for the arithmetic circuit but also the printed circuit board for mounting on a vehicle on which the solder paste having a high height for the power circuit and the power circuit is printed and the like are increased with the electric driving of the vehicle, and there are cases where a large difference in the height of the solder paste within one inspection range occurs.

As a result, it may be difficult to take all the solder pastes (the height range from the solder paste located at the lowest position to the solder paste located at the highest position) within one inspection range within the depth of field of the imaging device.

That is, in the conventional configuration in which the measurement of all the solder pastes in one inspection range is completed at a time, the focused image data cannot be acquired for all the solder pastes in one inspection range, and the measurement accuracy may be lowered.

The above-described problems are not necessarily limited to three-dimensional measurement of solder paste printed on a printed circuit board, and are also included in other fields of three-dimensional measurement. Of course, the method is not limited to the phase shift method.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a three-dimensional measurement apparatus and a three-dimensional measurement method that can improve measurement accuracy and the like.

Disclosure of Invention

Hereinafter, each technical means suitable for solving the above problems will be described. In addition, according to needs, a specific action effect is added to the corresponding technical scheme.

Technical solution 1. a three-dimensional measuring apparatus for aligning a predetermined measuring means (e.g., a measuring head) with a predetermined measuring area (all or a part of the area of a predetermined object to be measured) on a predetermined object to be measured (e.g., a printed circuit board) and performing three-dimensional measurement on an object to be measured (e.g., solder paste) arranged in the measuring area by a predetermined three-dimensional measuring method (e.g., a pattern projection method),

the measurement unit includes:

a first irradiation unit capable of irradiating the measurement target region with predetermined light (for example, slit light) for performing height measurement of the measurement target region;

a second irradiation unit capable of irradiating the measurement target region with a predetermined pattern light for performing three-dimensional measurement of the measurement target; and

an imaging unit capable of imaging the region to be measured irradiated with the predetermined light or the predetermined pattern light,

the three-dimensional measuring device includes:

an area height acquisition unit that acquires height information of the region to be measured based on image data obtained by irradiating the predetermined light and being captured by the imaging unit;

a reference surface height acquisition unit that calculates height information of a measurement reference surface of each of the plurality of objects to be measured included in the region to be measured, based on height information of the region to be measured;

a focusing required range determining unit that determines focusing required ranges required to photograph the entire area of the measured object in the height direction in a focused state, based on the height information of the measurement reference surface, for the plurality of measured objects, respectively;

a correlation unit that performs a correlation between a height position of the measurement unit (at least the photographing unit) and the measured object as a measurement object at the height position based on a focus required range of the plurality of measured objects and a depth of field of the photographing unit;

a height adjustment unit configured to be capable of moving the measurement unit (at least the imaging unit) in a height direction and sequentially positioning the measurement unit (at least the imaging unit) with respect to a predetermined height position determined by the association; and

and a three-dimensional measurement unit capable of performing three-dimensional measurement of the measurement target at a predetermined height position at which the measurement unit (at least the imaging unit) is positioned, based on image data captured by the imaging unit under the predetermined pattern light irradiated from the second irradiation unit.

According to claim 1, the configuration is as follows: when three-dimensional measurement of a measurement target in a predetermined measurement region on a measurement target is performed, height adjustment of a measurement means (at least an imaging means) is performed.

More specifically, first, a predetermined light is irradiated to a measurement target region, and the height of the measurement target region is measured. Then, the height of the measurement reference surface of each object to be measured included in the area to be measured is obtained based on the height information of the area to be measured, and a required focusing range necessary for imaging the entire area in the height direction of each object to be measured in a focused state is determined.

Next, the association between the height position of the measurement unit (at least the imaging unit) and the measured object as the measurement object at the height position is performed based on the focus required range of each measured object and the depth of field of the imaging unit. Then, the measuring means (at least the imaging means) is sequentially moved with respect to the predetermined height position specified here, and solder measurement is performed on the object to be measured which is the object to be measured at the height position.

With this configuration, three-dimensional measurement can be performed using image data captured in an appropriate in-focus state for all the measured objects (height range from the measured object located at the lowest position to the measured object located at the highest position) within one measured area. As a result, the measurement accuracy can be improved.

The three-dimensional measurement device according to claim 1 is characterized by comprising:

a number-of-times determination unit that determines whether the number of times of the three-dimensional measurement required in the measured region increases in a case where the three-dimensional measurement by the three-dimensional measurement unit is performed at an initial height position when the measurement unit is aligned to the measured region in a previous stage of the height adjustment by the height adjustment unit,

performing the first three-dimensional measurement by the three-dimensional measurement unit at the first height position without increasing the number of three-dimensional measurements.

According to the above-described aspect 2, since the number of times the measurement unit (at least the imaging unit) moves in the height direction (the number of times of height adjustment) is reduced by 1, the total measurement time for one measurement target area can be shortened.

The three-dimensional measurement device according to claim 1 or 2, further comprising:

a distance determination unit configured to determine, when the height adjustment by the height adjustment unit is performed, which of a case where a moving distance from a first height position at which the measurement unit is aligned to the measurement target area is moved to a lowermost height position and a case where the measurement unit is moved to an uppermost height position among a plurality of height positions of the measurement unit (at least the imaging unit) specified by the association is shorter,

the height adjusting means moves the measuring means (at least the imaging means) from the first height position to the lower-most height position or the upper-most height position by a shorter movement distance.

According to claim 3, the total moving distance in the height direction required before the measurement of all the objects to be measured in one region to be measured is completed can be shortened. As a result, the total measurement time for one measurement target region can be shortened.

Claim 4. in the three-dimensional measuring apparatus according to any one of claims 1 to 3,

the association means associates the height position of the measurement means (at least the imaging means) with the object to be measured with respect to each of the plurality of objects to be measured, so that at least one depth of field exists in the entire focusing range including the object to be measured.

According to claim 4, since three-dimensional measurement can be performed simultaneously without dividing the entire height direction of the object to be measured at least once, the measurement accuracy can be improved.

A three-dimensional measurement method according to claim 5 is a three-dimensional measurement method for aligning a predetermined measurement unit (e.g., a measurement head) having a predetermined irradiation unit and a predetermined imaging unit with a predetermined measurement area (all or a part of the measurement area) on a predetermined measurement object (e.g., a printed circuit board) and performing three-dimensional measurement on the measurement object (e.g., solder paste) placed in the measurement area by a predetermined three-dimensional measurement method (e.g., a pattern projection method), the three-dimensional measurement method including:

a region height acquisition step of acquiring height information of the region to be measured based on image data obtained by irradiating the region to be measured with predetermined light (for example, slit light) and capturing the image;

a reference surface height acquisition step of calculating height information of a measurement reference surface of each of the plurality of objects to be measured included in the region to be measured based on the height information of the region to be measured;

a focusing required range determining step of determining, for each of the plurality of objects to be measured, a focusing required range required for photographing the entire area of the object to be measured in the height direction in a focused state based on the height information of the measurement reference surface;

a correlation step of performing correlation between a height position of the measurement unit (at least the photographing unit) and the measured object as a measurement object at the height position based on a focus required range of the plurality of measured objects and a depth of field of the photographing unit;

a height adjustment step of moving the measurement means (at least the imaging means) in a height direction and sequentially positioning the measurement means (at least the imaging means) with respect to a predetermined height position determined by the association;

and a three-dimensional measurement step of performing three-dimensional measurement of the measurement target at a predetermined height position at which the measurement unit (at least the imaging unit) is positioned, based on image data obtained by irradiating the measurement target region with a predetermined pattern light and imaging the pattern light.

According to claim 5, the same operational effects as those of claim 1 are obtained.

The three-dimensional measurement method according to claim 6 is the three-dimensional measurement method according to claim 5, including:

a number-of-times determination step of determining whether or not the number of times of the three-dimensional measurement required in the region to be measured increases in a case where the three-dimensional measurement is performed at an initial height position when the measurement unit is aligned to the region to be measured at a stage prior to the height adjustment step,

performing an initial three-dimensional measurement at the initial height position without increasing the number of three-dimensional measurements.

According to claim 6, the same effects as those of claim 2 are obtained.

The three-dimensional measurement method according to claim 5 or 6, further comprising:

a distance determination step of determining, when the height adjustment step is performed, which of a movement distance from a first height position at which the measurement means is aligned to the measurement target area is shorter when the measurement means is moved to a lowermost height position and a movement distance from the measurement means to an uppermost height position among a plurality of height positions of the measurement means (at least the imaging means) determined by the association is shorter,

in the height adjusting step, the measuring means (at least the imaging means) is moved from the first height position to one of the lowest height position and the highest height position, which has a shorter moving distance.

According to claim 7, the same operational effects as those of claim 3 are obtained.

The three-dimensional measurement method according to claim 8, characterized in that, in any one of claims 5 to 7,

in the associating step, the height position of the measuring means (at least the imaging means) and the object to be measured are associated with each other so that at least one depth of field exists in the entire focusing range including the object to be measured.

According to claim 8, the same effects as those of claim 4 are obtained.

The "object to be measured" may be, for example, a printed board on which solder paste is printed (or applied). That is, by using the three-dimensional measuring device (three-dimensional measuring method) described in each of the above-described embodiments, three-dimensional measurement of solder paste printed on a printed board or the like can be performed. Further, in the inspection of the solder paste, the quality of the solder paste can be determined based on the measurement value. Therefore, in this inspection, the above-described operation and effect are exhibited, and the quality determination can be performed with high accuracy. As a result, the inspection accuracy in the solder inspection can be improved.

The "predetermined pattern light for three-dimensional measurement" may be a pattern light (stripe pattern) having a light intensity distribution in a stripe shape (e.g., a sine wave shape), or the like. By irradiating the pattern light, three-dimensional measurement by a phase shift method can be performed. As a result, the measurement accuracy of three-dimensional measurement can be improved.

In a configuration in which three-dimensional measurement is performed based on a difference in luminance values of a plurality of image data captured and acquired under pattern lights having different phases, as in the phase shift method, even if an error in luminance values is small, there is a possibility that measurement accuracy is greatly affected. Therefore, the operation and effect of each unit described above are more effective in a configuration in which three-dimensional measurement is performed by the phase shift method. In particular, the light intensity distribution (waveform) of the pattern light having a sinusoidal light intensity distribution is likely to be distorted, and thus higher accuracy is required.

The three-dimensional measurement means (three-dimensional measurement step) in the three-dimensional measurement device (three-dimensional measurement method) using the phase shift method is configured to perform three-dimensional measurement of the measurement target by the phase shift method based on a plurality of sets of image data having different light intensity distributions, which are captured by irradiating predetermined pattern light with different phases a plurality of times, for example.

Drawings

Fig. 1 is a schematic diagram showing a schematic configuration of a substrate inspection apparatus.

Fig. 2 is a partially enlarged sectional view of the printed substrate.

Fig. 3 is a schematic plan view showing a schematic configuration of a printed board.

Fig. 4 is a block diagram showing an electrical configuration of the substrate inspection apparatus.

Fig. 5 is a flowchart showing the in-field inspection processing.

Fig. 6 is a schematic diagram showing an example of correspondence between the height position of the measuring head and the solder paste as the object of measurement at the height position.

Fig. 7 is a schematic diagram showing an example of correspondence between the height position of the measuring head and the solder paste as the object of measurement at the height position.

Detailed Description

Hereinafter, one embodiment will be described with reference to the drawings. First, the structure of the printed circuit board 1 serving as the measurement target in the present embodiment will be described in detail (see fig. 2 and 3). Fig. 2 is a partially enlarged sectional view of the printed substrate 1. Fig. 3 is a schematic plan view showing a schematic configuration of the printed board 1.

As shown in fig. 2 and 3, the printed circuit board 1 has electrode patterns 3A and lands 3B made of copper foil formed on the surface of a flat base substrate 2 made of glass epoxy resin or the like. On the surface of the base substrate 2, a resist film 4 is coated except for the pad 3B and its vicinity. Then, the solder paste 5 to be an object to be measured is printed (or applied) on the pad 3B.

The printed board 1 according to the present embodiment is a printed board mounted on a vehicle such as an electric vehicle, for example, and includes a power circuit portion PA on which electronic components such as an inverter circuit that flows a relatively large load current are mounted, and a control circuit portion PB on which electronic components such as a control circuit that controls the power circuit PA that flows a relatively small signal current are mounted.

Next, the substrate inspection apparatus 10 (see fig. 1) constituting the three-dimensional measurement apparatus according to the present embodiment will be described in detail. Fig. 1 is a schematic diagram showing a schematic configuration of a substrate inspection apparatus 10. Hereinafter, the left-right direction of the drawing sheet in fig. 1 is referred to as the "X-axis direction", the front-back direction of the drawing sheet is referred to as the "Y-axis direction", and the up-down direction (vertical direction) of the drawing sheet is referred to as the "Z-axis direction".

The board inspection apparatus 10 is a solder print inspection apparatus that inspects the print state of the solder paste 5 printed on the printed board 1. The substrate inspection apparatus 10 includes: a transport mechanism 11 for transporting and positioning the printed circuit board 1; a measuring head 12 as a measuring unit for performing measurement of the printed substrate 1; and a control device 40 for performing various controls, image processing, and arithmetic processing (see fig. 4) in the substrate inspection apparatus 10 such as drive control of the transport mechanism 11 and the measurement head 12.

The conveyance mechanism 11 includes: a pair of conveyance rails 11a arranged along a conveyance direction (Y-axis direction) of the printed circuit board 1; an endless conveyor belt 11b rotatably disposed with respect to each of the conveyor rails 11 a; a driving means (not shown) such as a motor for driving the conveyor belt 11 b; and a chuck mechanism (not shown) for positioning the printed circuit board 1 at a predetermined position, and is driven and controlled by the control device 40.

With the above configuration, both side edge portions in the width direction (X-axis direction) orthogonal to the conveyance direction of the printed circuit board 1 carried into the board inspection apparatus 10 are inserted into the conveyance rails 11a and placed on the conveyance belts 11 b. Subsequently, the conveyor belt 11b starts operating, and the printed circuit board 1 is conveyed to a predetermined inspection position. When the printed substrate 1 reaches the inspection position, the conveyance belt 11b is stopped, and the chuck mechanism is operated. By the operation of the chuck mechanism, the transport belt 11b is pushed up, and both side edge portions of the printed circuit board 1 are sandwiched between the transport belt 11b and the upper edge portion of the transport rail 11 a. Thereby, the printed circuit board 1 is positioned and fixed at the inspection position. When the inspection is finished, the fixing of the chuck mechanism is released, and the conveyor belt 11b starts to operate. Thereby, the printed circuit board 1 is carried out from the board inspection apparatus 10. Of course, the configuration of the conveying mechanism 11 is not limited to the above-described embodiment, and other configurations may be adopted.

The measuring head 12 is disposed above the conveyance path (the pair of conveyance rails 11a) of the printed circuit board 1. The measuring head 12 includes: an irradiation device 13 capable of irradiating a predetermined inspection range W (see fig. 3) on the printed circuit board 1 with slit light (line light) from obliquely above; a projection device 14 capable of projecting pattern light having a striped light intensity distribution (hereinafter referred to as a "stripe pattern") from obliquely above a predetermined inspection range W; a camera 15 as an imaging means for imaging the inspection area W irradiated with the slit light or the inspection area W projected with the stripe pattern from directly above; an X-axis moving mechanism 16 (see fig. 4) that is movable in the X-axis direction; a Y-axis moving mechanism 17 (see fig. 4) that is movable in the Y-axis direction; and a Z-axis moving mechanism 18 (see fig. 4) that is movable in the Z-axis direction, and the measuring head 12 is driven and controlled by the control device 40.

As shown in fig. 3, the predetermined inspection range W on the printed circuit board 1 matches the imaging field of view (imaging range) K of the camera 15, and is one of a plurality of predetermined regions (inspection ranges W1, W2, W3, and W4) on the printed circuit board 1. Therefore, the size of the inspection range W is substantially the same as the size of the photographing field of view K of the camera 15. The "inspection range W" corresponds to the "measurement target region" in the present embodiment.

The control device 40 can move the measuring head 12 (imaging field of view K) to a position above an arbitrary inspection range W on the printed circuit board 1 fixedly positioned at the inspection position by controlling the driving of the X-axis moving mechanism 16 and the Y-axis moving mechanism 17. Then, the measuring head 12 is sequentially moved to a plurality of inspection ranges W1 to W4 set on the printed circuit board 1, and the in-view inspection process is executed in each inspection range W, thereby performing the solder printing inspection over the entire area of the printed circuit board 1.

The control device 40 can change the relative height relationship between the measurement head 12 (camera 15) and the printed circuit board 1 by controlling the driving of the Z-axis moving mechanism 18. Therefore, the Z-axis moving mechanism 18 and the function of the control device 40 for controlling the driving thereof constitute "height adjusting means" in the present embodiment.

The irradiation device 13 is a well-known device, and therefore, not shown in detail, includes a light source that emits predetermined light, a conversion unit that converts light from the light source into slit light, and the like, and is driven and controlled by the control device 40. In the present embodiment, the printed circuit board 1 is configured to be irradiated with slit light from obliquely above in a plurality of rows parallel to the Y-axis direction. The "irradiation device 13" constitutes "a first irradiation unit" in the present embodiment, and "slit light" corresponds to "predetermined light for height measurement".

As shown in fig. 1, the projection device 14 includes: a light source 19 that emits predetermined light; a grating plate 20 that converts the light from the light source 19 into a fringe pattern; a projection lens unit 21 as a projection optical system that images the fringe pattern generated by the grating plate 20 on the printed substrate 1; and a driving mechanism (not shown) such as a piezoelectric element that displaces the grating plate 20 by sliding and shifts the phase of the fringe pattern projected on the printed substrate 1, and the projection device 14 is driven and controlled by the control device 40.

The projection device 14 is disposed such that the optical axis J1 is parallel to the X-Z plane and is inclined by a predetermined angle α (for example, 30 °) with respect to the Z-axis direction. The "projection device 14" constitutes "the second irradiation unit" in the present embodiment, and the "stripe pattern" corresponds to "predetermined pattern light for performing three-dimensional measurement".

The light source 19 is a halogen lamp that emits white light. The light emitted from the light source 19 is collimated by a pretreatment lens group, not shown, and enters the grating plate 20 along the optical axis J1. As the light source 19, another light source such as a white LED may be used instead of the halogen lamp.

The grating plate 20 is formed by printing (depositing) a grating pattern (not shown) on a substrate formed of a predetermined light-transmitting material (e.g., glass, acrylic resin, or the like) in a flat plate shape or a film shape. The grating pattern is configured such that light transmitting portions, which are formed linearly in the Y-axis direction and transmit light at a predetermined transmittance, and light shielding portions, which are formed linearly in the Y-axis direction and shield at least a part of the light, are alternately arranged on the X-Z plane.

The projection lens unit 21 is configured by a double-sided telecentric lens (double-sided telecentric optical system) integrally including an incident-side lens and an exit-side lens. However, in fig. 1, the projection lens unit 21 is illustrated as one lens for simplicity.

Here, the incident side lens condenses the light (stripe pattern) emitted from the grating plate 20, and has a telecentric structure in which the incident side optical axis J1 is parallel to the principal ray. The exit lens is for forming an image of light (stripe pattern) transmitted through the entrance lens on the printed circuit board 1, and has a telecentric structure parallel to the principal ray on the exit optical axis J1.

In the projection apparatus 14 according to the present embodiment, the grating plate 20 is set so as to be inclined with respect to the optical axis J1 (however, the illustration is simplified in fig. 1) such that the fringe pattern projected on the printed circuit board 1 is focused over the entire projection range (substantially the same range as the imaging field of view K in the present embodiment), that is, such that the grating plate 20 and the main surface of the projection lens unit 21 satisfy the Scheimpflug condition with respect to the printed circuit board 1.

In the above configuration, in the projection apparatus 14, light emitted from the light source 19 enters the grating plate 20. Then, the light in the transmission grating 20 is emitted as a stripe pattern and projected onto the printed board 1 via the projection lens unit 21. Thus, in the present embodiment, a stripe pattern parallel to the transport direction (Y-axis direction) of the printed circuit board 1 is projected.

In addition, generally, light passing through the grating is not completely parallel light, and a halftone area is generated at a boundary portion between a "light portion" and a "dark portion" of a projected stripe pattern due to diffraction action or the like at a boundary portion between a light transmitting portion and a light shielding portion. Therefore, the stripe pattern projected on the printed circuit board 1 becomes a pattern light having a sinusoidal light intensity distribution along a direction (X-axis direction) orthogonal to the transport direction (Y-axis direction) of the printed circuit board 1.

As shown in fig. 1, the camera 15 has: an imaging element 15a having a light receiving surface on which a plurality of light receiving elements are two-dimensionally arrayed; and an imaging lens unit 15b as an imaging optical system for forming an image in an imaging field K (an inspection range W of the printed circuit board 1 on which the stripe pattern is projected) on the imaging element 15a, wherein an optical axis J2 of the camera 15 is set along a vertical direction (Z-axis direction) perpendicular to the upper surface of the printed circuit board 1. In the present embodiment, a CCD area sensor is used as the image pickup device 15 a.

The imaging lens unit 15b is configured by a double-sided telecentric lens (double-sided telecentric optical system) integrally including an object side lens, an aperture stop, an image side lens, and the like. However, in fig. 1, the photographing lens unit 15b is illustrated as one lens for simplicity.

Here, the object side lens has a telecentric structure in which the reflected light from the printed circuit board 1 is condensed and is parallel to the principal ray on the object side optical axis J2. The image side lens is for forming an image of the light having passed through the aperture stop from the object side lens on the light receiving surface of the imaging element 15a, and has a telecentric structure in which the image side optical axis J2 is parallel to the principal ray.

Image data captured and acquired by the camera 15 is converted into a digital signal inside the camera 15 as needed, and then input to the control device 40 in the form of a digital signal and stored in an image data storage device 44 described later. The control device 40 performs image processing, arithmetic processing, and the like, which will be described later, based on the image data.

Next, an electrical configuration of the control device 40 will be described with reference to fig. 4. Fig. 4 is a block diagram showing an electrical configuration of the substrate inspection apparatus 10.

As shown in fig. 4, the control device 40 includes: a microcomputer 41 for managing the overall control of the substrate inspection apparatus 10; an input device 42 as an "input unit" constituted by a keyboard, a mouse, a touch panel, and the like; a display device 43 as a "display unit" having a display screen such as a CRT or a liquid crystal; an image data storage 44 for storing image data and the like captured and acquired by the camera 15; an operation result storage unit 45 for storing various operation results such as a three-dimensional measurement result obtained based on the image data; and a setting data storage device 46 for storing various information such as the Gerber (Gerber) data in advance.

The microcomputer 41 includes a CPU41a as arithmetic means, a ROM41b for storing various programs, a RAM41c for temporarily storing various data such as arithmetic data and input/output data, and the like, and the microcomputer 41 is electrically connected to the devices 42 to 46 and the like. The controller also has a function of performing input/output control of various data and signals with the devices 42 to 46.

The setting data storage device 46 stores a plurality of inspection ranges W1 to W4 set on the printed circuit board 1, information on the movement order of the imaging field of view K of the camera 15 for these inspection ranges, and the like. Here, the "moving order of the imaging field of view K" refers to an order in which the imaging field of view K of the camera 15 is determined for a plurality of inspection ranges W1 to W4 set on the printed circuit board 1.

The setting of the plurality of inspection ranges W (W1 to W4 in the present embodiment) for the printed circuit board 1 and the moving order of the imaging field of view K for them is automatically performed by a predetermined program or manually performed by an operator in advance based on the gurber data or the like.

For example, in the example shown in fig. 3, the following are set: the inspection is started with the upper right inspection range W1 as a starting point, and the imaging field of view K is moved in the order of "inspection range W1" → "inspection range W2" → "inspection range W3" → "inspection range W4", and the inspection is performed for each inspection range W, thereby inspecting the entire area of the printed circuit board 1.

Next, an inspection routine of the printed circuit board 1 performed by the board inspection apparatus 10 will be described in detail. This check routine is executed by the control device 40 (microcomputer 41).

As described above, when the printed circuit board 1 carried into the board inspection apparatus 10 is fixed and positioned at a predetermined inspection position, the control apparatus 40 first performs the position detection process of the printed circuit board 1.

More specifically, the control device 40 detects a positioning mark (not shown) attached to the printed circuit board 1, and calculates positional information (tilt, positional deviation, etc.) of the printed circuit board 1 based on positional information (coordinates) of the detected mark and positional information (coordinates) of the mark stored in the gurley data. This ends the position detection process of the printed circuit board 1. Then, correction processing for correcting a deviation in the relative positional relationship between the measurement head 12 (camera 15) and the printed substrate 1 is performed based on the positional information of the printed substrate 1.

Thereafter, the control device 40 controls the driving of the X-axis movement mechanism 16 and the Y-axis movement mechanism 17, and executes the movement processing of the measurement head 12 to the position corresponding to the first inspection range W1 of the printed circuit board 1 in accordance with the inspection procedure stored in the setting data storage device 46.

When the movement process of the measuring head 12 is completed and the imaging field of view K of the camera 15 matches the first inspection range W1 on the printed circuit board 1, the in-field inspection process is executed in accordance with the inspection range W1. The in-field inspection process will be described in detail later (the same applies to the in-field inspection process for the other inspection ranges W2, W3, and W4).

After that, when the in-view inspection process for the first inspection range W1 on the printed circuit board 1 is completed, the movement process for moving the measuring head 12 to the position corresponding to the second inspection range W2 on the printed circuit board 1 is started in accordance with the inspection procedure stored in the setting data storage device 46.

Similarly, the in-view inspection process is performed on the second to fourth inspection ranges W2 to W4 on the printed circuit board 1, and the solder print inspection of the entire printed circuit board 1 is completed.

Next, the in-field inspection process performed in each inspection range W of the printed circuit board 1 will be described in detail with reference to the flowchart of fig. 5. The in-field inspection process is executed by the control device 40 (microcomputer 41).

First, the control device 40 measures the height of the inspection range W in step S1. Here, the approximate height position of the printed substrate 1 in the inspection range W is measured by measuring the height position of the surface of the pad 3B, the surface of the resist film 4, and the like in the inspection range W. The processing step of step S1 corresponds to the "area height acquisition step" in the present embodiment, and the "area height acquisition means" is configured by the function of the control device 40 that executes the processing step.

Specifically, in the present embodiment, the height measurement is performed by a known Light-Section Method. That is, while the irradiation device 13 is driven to irradiate the inspection area W with a plurality of parallel lines of slit light from obliquely above, the inspection area W is imaged by the camera 15. Then, the height of the inspection range W (printed circuit board 1) is measured by analyzing the image of the slit light based on the principle of triangulation based on the image data acquired by the camera 15. The height information (various information such as height, warp, and inclination) of the inspection range W acquired here is stored in the calculation result storage device 45.

Next, in step S2, the control device 40 calculates the height position of the surface of each pad 3B that becomes the measurement reference surface of each solder paste 5. The processing step related to step S2 corresponds to the "reference surface height acquisition step" in the present embodiment, and the "reference surface height acquisition means" is configured by the function of the control device 40 that executes the processing step.

Specifically, in the present embodiment, based on the height information of the inspection range W acquired in step S1, the approximate height positions of the surfaces of all the pads 3B located within the inspection range W are calculated with reference to various information such as the gurley data stored in advance in the setting data storage device 46. The height information of the surface of each pad 3B calculated here is stored in the operation result storage device 45. In step S2, since the level of strictness is not required, the height of the surface of the resist film 4 in the vicinity of the pad 3B may be replaced with the height of the measurement reference surface.

Next, the control device 40 calculates a required focus range required to photograph the entire area of the solder paste 5 in the height direction in a focused state for all the solder pastes 5 within the inspection range W, respectively, in step S3. The processing step related to step S3 corresponds to the "focus required range specifying step" in the present embodiment, and the "focus required range specifying means" is configured by the function of the control device 40 that executes the processing step.

Specifically, first, the height position of the surface of each pad 3B acquired in step S2 is set as the lower limit value of the focus required range of the solder paste 5 printed on the pad 3B. Next, a value obtained by adding the maximum allowable height value T (see fig. 6 and 7) of the acceptable solder pastes 5 stored in advance in the setting data storage device 46 to the lower limit value is set as the upper limit value of the focus required range of each solder paste 5.

Next, in step S4, the control device 40 performs association of the height position of the measurement head 12 and the solder paste 5 as the measurement object at the height position. The processing step related to step S5 corresponds to the "related step" in the present embodiment, and the function of the control device 40 that executes the processing step constitutes "related means".

In detail, the association is made based on the focus required range of each solder paste 5 acquired in step S3 and the depth of field of the camera 15 stored in advance in the setting data storage device 46.

Here, the association will be described with reference to 2 examples shown in fig. 6 and 7. Fig. 6 and 7 are schematic diagrams showing an example of the relationship between the height position of the measuring head 12 and the solder paste 5 to be measured at the height position.

In fig. 6 and 7, when it is assumed that 9 solder pastes 5 (solder pastes 5A to 5I) exist within the predetermined inspection range W, the 9 solder pastes 5A to 5I are arranged at the height positions thereof while disregarding the positional relationship in the horizontal direction (X-Y plane).

In fig. 6 and 7, "Q0" represents the depth of field when the measuring head 12 is positioned in the inspection range W at the "initial height position". Likewise, "Q1", "Q2", and "Q3" respectively denote the depths of field for the case where the measuring head 12 is located at the "first height position", "second height position", and "third height position" in the Z-axis direction.

That is, in the example shown in fig. 6 and 7, the correlation is performed such that four of the solder pastes 5A, 5B, 5C, and 5D can be photographed and measured in a focused state at the depth of field Q1 when the measuring head 12 is in the "first height position", two of the solder pastes 5E and 5F can be photographed and measured in a focused state at the depth of field Q2 when the measuring head 12 is in the "second height position", and three of the solder pastes 5G, 5H, and 5I can be photographed and measured in a focused state at the depth of field Q3 when the measuring head 12 is in the "third height position".

Next, in step S5, referring to the result of the correlation performed in step S4, when the "solder measurement" described later (three-dimensional measurement of solder paste 5 by the phase shift method) is performed at the current height position of the measuring head 12, that is, the "first height position" at which the measuring head 12 is aligned to the inspection range W, the control device 40 determines whether the number of times of the "solder measurement" required in the inspection range W increases.

The processing step related to step S5 corresponds to the "number determination step" in the present embodiment, and the function of the control device 40 that executes this processing step constitutes "number determination means".

If an "affirmative determination" is made here, that is, if the number of times of determination "solder measurement" is increased, the process proceeds to step S8, and if the determination is negative, that is, if the number of times of determination "solder measurement" is not increased, the process proceeds to step S6.

Then, the control device 40 performs initial "solder measurement" at the current height position (initial height position) in step S6.

For example, in the example of fig. 6 (case 1), even if the measuring head 12 maintains the "initial height position", it is in a state in which the solder pastes 5E, 5F can be photographed and measured in the in-focus state. In this case, the measuring head 12 first performs "solder measurement (first solder measurement in the inspection range W)" on the solder pastes 5E, 5F existing in the "depth of field Q0" at the "initial height position".

Thereafter, in the example of fig. 6 (case 1), for example, the measurement head 12 may move to the "first height position" to perform the "solder measurement (the second solder measurement in the inspection range W)" on the solder pastes 5A, 5B, 5C, 5D existing in the "depth of field Q1", and then the measurement head 12 may move to the "third height position" to perform the "solder measurement (the third solder measurement in the inspection range W)" on the solder pastes 5G, 5H, 5I existing in the "depth of field Q3".

That is, in the example of fig. 6 (case 1), the operation step of moving the measuring head 12 to the "second height position" can be omitted, and the number of times of movement in the Z-axis direction (the number of times of height adjustment) can be reduced by 1. In such a case, in the present embodiment, a negative determination is made in step S5 (determination is made that the number of times of "solder measurement" is not increased).

On the other hand, in the example of fig. 7 (case 2), three solder pastes 5C, 5D, and 5E can be photographed and measured in a focused state in a state where the measuring head 12 is kept at the "initial height position".

However, in this case, assuming that the measuring head 12 performs "solder measurement (first solder measurement in the inspection range W)" in the "initial height position" for the three solder pastes 5C, 5D, 5E existing within the "depth of field Q0", then, for example, the measuring head 12 must move to the "first height position" to perform "solder measurement (second solder measurement in the inspection range W)" for the solder pastes 5A, 5B existing within the "depth of field Q1", then move to the "second height position" to perform "solder measurement (third solder measurement in the inspection range W)" for the solder paste 5F existing within the "depth of field Q2", and then move to the "third height position" to perform "solder measurement (fourth solder measurement in the inspection range W)" for the solder pastes 5G, 5H, 5I existing within the "depth of field Q3", the number of "solder measurements" required was increased to four times.

In such a case, in the present embodiment, the determination at step S5 is affirmative (the number of determinations as "solder measurement" is increased). That is, by going through the processing procedure of step S5, for example, in the example of fig. 7 (case 2), the measuring head 12 does not perform the "solder measurement" related to the "depth of field Q0" at the "initial height position", for example, moves to the "first height position", the "solder measurement (the first solder measurement in the inspection range W)" is performed on the solder pastes 5A, 5B, 5C, 5D existing in the "depth of field Q1", and thereafter, moved to the "second height position", the "solder measurement (the second solder measurement in the inspection range W)" is performed on the solder pastes 5E, 5F existing within the "depth of field Q2", and thereafter, is moved to the "third height position", the "solder measurement (the third solder measurement in the inspection range W)" is performed on the solder pastes 5G, 5H, 5I existing in the "depth of field Q3", and the number of times of the required "solder measurement" becomes three.

In step S7 following step S6, the control device 40 determines whether or not "solder measurement" is completed for all the solder pastes 5 within the inspection range W. That is, it is determined whether or not "solder measurement" is completed for all the solder pastes 5 in the inspection range W by one "solder measurement" performed by the measuring head 12 for the "depth of field Q0" at the "initial height position".

In the case where an affirmative determination is made here, i.e., in the case where "solder measurement" is completed for all the solder pastes 5 within the inspection range W, the present process is directly ended. On the other hand, in the case where the determination in step S7 is negative, that is, in the case where "solder measurement" is not completed with respect to all the solder pastes 5 within the inspection range W, the process proceeds to step S8.

In step S8, the control device 40 determines whether the height adjustment of the measuring head 12 is necessary a plurality of times in order to measure the unmeasured solder paste 5.

In the case where an affirmative decision is made here, i.e. in the case where a plurality of height adjustments of the measuring head 12 is required, the process proceeds to step S11. On the other hand, if the determination is negative, that is, if the height adjustment of the measurement head 12 is only required once, the process proceeds to step S9.

In step S9, the control device 40 controls the driving of the Z-axis moving mechanism 18 to move the measuring head 12 to a predetermined height position and position the measuring head. In the next step S10, the control device 40 performs "solder measurement" on the unmeasured solder paste 5 at the height position. Then, the present process is ended. Details of the "solder measurement" will be described later.

The processing step related to step S9 (the same applies to steps S12, S14, and S16 described later) corresponds to the "height adjustment step" in the present embodiment, and the "height adjustment means" is configured by the function of the control device 40 that executes the processing step. The processing step (solder measurement) related to step S10 (the same applies to steps S13, S15, and S17 described later) corresponds to the "three-dimensional measurement step" in the present embodiment, and the function of the control device 40 that executes the processing step constitutes the "three-dimensional measurement means".

On the other hand, in step S11 to which an affirmative determination is made in step S8 and the process proceeds, the control device 40 determines whether or not the distance of movement of the measuring head 12 when moving to the lowermost height position is short, when moving from the current height position of the measuring head 12, that is, the "first height position" at which the measuring head 12 is positioned within the inspection range W, to the height position (lowermost height position) located at the lowermost height position among the plurality of height positions of the measuring head 12 determined by the association in step S4, and when moving to the height position (uppermost height position) located at the uppermost height position.

Further, since the movement distance of the measuring head 12 that sequentially rises from the lowermost height position in the Z-axis direction and the movement distance of the measuring head 12 that sequentially falls from the uppermost height position in the Z-axis direction are the same for the plurality of height positions specified by the above-described correlation, when the movement distance is shorter than the "first height position" of the lowermost height position or the uppermost height position, the total of the movement distances (total movement distance) that the measuring head 12 moves becomes shorter before the "solder measurement" is completed for all the solder pastes 5 in the inspection range W.

The processing step related to step S11 corresponds to the "distance determination step" in the present embodiment, and the "distance determination means" is configured by the function of the control device 40 that executes the processing step.

If the determination is positive, that is, if the moving distance of the measuring head 12 is determined to be short when the measuring head is moved to the lowermost height position, the process proceeds to step S12.

Then, the control device 40 controls the driving of the Z-axis moving mechanism 18 to move and position the measuring head 12 to the lowermost height position in step S12, and performs "solder measurement" for the lowermost height position in the next step S13. Thereafter, the process proceeds to step S16.

On the other hand, if the determination at step S11 is negative, that is, if the moving distance of the measuring head 12 when moving to the uppermost height position is determined to be short, the process proceeds to step S14.

Then, the control device 40 controls the driving of the Z-axis moving mechanism 18 to move and position the measuring head 12 to the uppermost height position in step S14, and performs "solder measurement" for the uppermost height position in the next step S15. Thereafter, the process proceeds to step S16.

For example, in the examples of fig. 6 and 7 (cases 1 and 2), both are the measurement head 12 moving to a "first height position" closer to the "initial height position" to perform a "solder measurement" within the "depth of field Q1".

Here, if the measurement head 12 moves to the "third height position" which is farther than the "first height position" and the "solder measurement" related to the "depth of field Q3" is performed first, the total movement distance of the measurement head 12 moves becomes long until the "solder measurement" is completed for all the solder pastes 5 in the inspection range W.

In step S16, the control device 40 drive-controls the Z-axis movement mechanism 18 to move and position the measuring head 12 to the unmeasured height position closest to the current height position, and in the next step S17, performs "solder measurement" relating to this height position. Thereafter, the process proceeds to step S18.

In step S18, the control device 40 determines whether "solder measurement" is completed for all the solder pastes 5 within the inspection range W. Here, in the case where an affirmative determination is made, that is, in the case where "solder measurement" is completed for all the solder pastes 5 within the inspection range W, the present process is directly ended.

On the other hand, if the determination in step S18 is negative, that is, if "solder measurement" is not completed for all the solder pastes 5 in the inspection range W, the process proceeds to step S16 again, and the series of processes described above is repeated until "solder measurement" is completed for all the solder pastes 5 in the inspection range W.

Next, the "solder measurement (three-dimensional measurement of the solder paste 5 by the phase shift method)" performed in the above-described step S10 and the like will be described in detail.

In the "solder measurement" according to the present embodiment, four times of imaging processing is performed on the inspection range W under the stripe patterns having different phases while changing the phase of the stripe pattern projected from the projection device 14, thereby acquiring four sets of image data having different light intensity distributions. The following description is made in detail.

As described above, when the height adjustment of the measurement head 12 is completed within the predetermined inspection range W, the control device 40 first slides and displaces the grating plate 20 of the projection device 14, and sets the position of the grating pattern formed on the grating plate 20 to a predetermined reference position (for example, a position of the phase "0 °").

When the positioning of the grating plate 20 is completed, the control device 40 causes the light source 19 of the projection device 14 to emit light to project a predetermined fringe pattern, and also controls the driving of the camera 15 to execute the first shooting process in the fringe pattern.

After that, the control device 40 turns off the light source 19 and slides and shifts the grating plate 20 at the same time as the end of the first imaging process in the predetermined fringe pattern. Specifically, the position of the grating pattern formed on the grating plate 20 is slidingly displaced from the reference position to a second position where the phase of the fringe pattern is shifted by a quarter pitch (90 °).

When the sliding displacement of the grating plate 20 is completed, the control device 40 causes the light source 19 to emit light to project a predetermined fringe pattern, and also controls the driving of the camera 15 to execute the second shooting process in the fringe pattern.

Thereafter, by repeating the same processing, four sets of image data having different light intensity distributions are acquired for each of the stripe patterns having different phases of 90 ° (each quarter pitch). Thus, four sets of image data obtained by shifting the phase of the stripe pattern having a sinusoidal light intensity distribution by 90 ° each time can be acquired.

Then, the controller 40 performs three-dimensional measurement (height measurement of each coordinate) of the solder paste 5 to be measured at the height position by a known phase shift method based on the four sets of image data (four sets of luminance values of each coordinate) relating to the predetermined height position acquired as described above. The three-dimensional measurement result is stored in the operation result storage means 45.

Here, a well-known phase shift method will be explained. The light intensities (luminances) I0, I1, I2, and I3 at predetermined coordinate positions on the printed circuit board 1 in the four sets of image data can be represented by the following formulas (1), (2), (3), and (4), respectively.

I0＝αsinθ+β…(1)

I1＝αsin(θ+90°)+β＝αcosθ+β…(2)

I2＝αsin(θ+180°)+β＝-αsinθ+β…(3)

I3＝αsin(θ+270°)+β＝-αcosθ+β…(4)

Wherein, α: gain, β: offset, θ: phase of the fringe pattern.

Then, by solving equations (1), (2), (3), and (4) above for the phase θ, equation (5) below can be derived.

θ＝tan-1{(I0-I2)/(I1-I3)}…(5)

By using the phase θ calculated in this way, the height (Z) in each coordinate (X, Y) on the printed substrate 1 can be obtained based on the principle of triangulation.

Next, the control device 40 performs a process of determining whether or not the print state of the solder paste 5 is good based on the three-dimensional measurement result (height data in each coordinate) obtained as described above. Specifically, the controller 40 detects a printing range of the solder paste 5 that is longer than a predetermined length than a determination value determined for each pad 3B (pad for the power circuit portion PA, pad for the control circuit portion PB) based on the measurement results of the solder pastes 5 obtained as described above, and calculates the amount of the solder paste 5 after printing by integrating the heights of the respective portions within the range.

Next, the controller 40 compares the data such as the position, area, height, or amount of each solder paste 5 thus obtained with reference data (such as the gurber data) stored in advance in the setting data storage 46, and determines whether the printing state of the solder paste 5 is good or not based on whether or not the comparison result is within an allowable range. The result of the quality determination of each solder paste 5 is stored in the calculation result storage device 45.

Then, the control device 40 completes "solder measurement (including quality determination)" for all the solder pastes 5 in the inspection range W, and moves the measuring head 12 to the next inspection range W when the in-view inspection processing according to the inspection range W is completed. Thereafter, the above-described series of processes are repeated in all inspection ranges W1 to W4 on the printed circuit board 1, whereby the solder print inspection of the entire printed circuit board 1 is completed.

As described above in detail, according to the present embodiment, the configuration is such that: when three-dimensional measurement (solder measurement) of the solder paste 5 in a predetermined inspection range W on the printed substrate 1 is performed, height adjustment of the measuring head 12 is performed.

More specifically, first, the slit light is irradiated from the irradiation device 13 to the inspection area W, and the height of the inspection area W is measured. Next, the height of the surface of each pad 3B serving as a measurement reference surface of each solder paste 5 included in the inspection range W is obtained based on the height information of the inspection range W, and a required focusing range necessary for imaging the entire area of each solder paste 5 in the height direction in a focused state is determined.

Next, based on the required focusing range of each solder paste 5 and the depth of field of the camera 15, the height position of the measuring head 12 and the solder paste 5 to be measured at the height position are associated with each other. Then, the measuring head 12 is sequentially moved with respect to the predetermined height position determined here, and solder measurement is performed on the solder paste 5 which is the object of measurement at the height position.

With this configuration, three-dimensional measurement can be performed using image data photographed in an appropriate in-focus state for all the solder pastes 5 within one inspection range W (a range of heights from the solder paste 5 at the lowest position to the solder paste 5 at the highest position). As a result, the measurement accuracy can be improved.

In the present embodiment, in the step of associating the height position of the measuring head 12 with the solder paste 5 to be measured at the height position (step S4), the following configuration is adopted in the examples shown in fig. 6 and 7: the plurality of solder pastes 5 are associated with each other so that at least one depth of field of the camera 15 including the entire focus range of the solder paste 5 exists.

Thereby, three-dimensional measurement (solder measurement) can be simultaneously performed at least once without dividing the entire height direction of the solder paste 5, and therefore, improvement in measurement accuracy can be achieved.

In the above embodiment, when the "first height position" is aligned to the inspection range W, it is determined whether the number of "solder measurements" required in the inspection range W increases (step S5), and when it is determined that the number of "solder measurements" does not increase, the first "solder measurement" is performed at the "first height position" (step S6).

This reduces the number of times the measuring head 12 is moved in the height direction (the number of times the height is adjusted) by 1, and therefore the total measurement time for one inspection range W can be shortened.

In the present embodiment, when it is determined that the "first height position" when the measuring head 12 is positioned to the inspection range W requires a plurality of height adjustments (step S8), the moving distance of the measuring head 12 is shortened when the measuring head 12 is moved to one of the lowermost height position and the uppermost height position among the plurality of height positions to be moved (step S11), and the measuring head 12 is moved to the shorter one (steps S12 and S14).

Thereby, the total moving distance in the height direction required to complete the measurement of all the solder pastes 5 in one inspection range W can be shortened. As a result, the total measurement time for one inspection range W can be shortened.

The present invention is not limited to the description of the above embodiments, and may be implemented as follows, for example. Needless to say, other application examples and modifications not illustrated below are also possible.

(a) In the above-described embodiment, the three-dimensional measuring device according to the present invention is embodied as the board inspection device (solder print inspection device) 10 that inspects the print state of the solder paste 5 printed on the printed board 1, but is not limited to this, and may be embodied as a device that inspects other objects such as electronic components mounted on the printed board. Of course, an object different from the substrate may be used as the measurement target to perform three-dimensional measurement.

(b) In the above embodiment, the four inspection ranges W1 to W4 are set on the printed circuit board 1 as the regions to be measured so as to match the imaging field of view K of the camera 15, but the allocation of the regions to be measured is not limited to this. For example, the entire area of the printed circuit board 1 may be set as one measurement area.

In the above embodiment, the entire area of the printed circuit board 1 is inspected by sequentially moving the measuring head 12 in the XY axis direction with respect to the four inspection ranges W1 to W4 fixed to the printed circuit board 1 at predetermined positions. Without being limited thereto, the following configuration may be adopted: the entire area of the printed substrate 1 is inspected by moving the printed substrate 1 in the XY-axis direction while the measuring head 12 is fixed in the XY-axis direction.

(c) In the above embodiment, the configuration is such that: in addition to performing three-dimensional measurement (solder measurement) by the phase shift method, four sets of image data in which the phases of the stripe patterns differ by 90 ° are acquired, but the number of phase shifts and the amount of phase shift are not limited to these. Other numbers of phase shifts and amounts of phase shifts that can be measured three-dimensionally by phase shift methods may also be used.

For example, three-dimensional measurement may be performed by acquiring three sets of image data that are 120 ° (or 90 °) out of phase, or three-dimensional measurement may be performed by acquiring two sets of image data that are 180 ° (or 90 °) out of phase.

(d) In the above-described embodiment, the pattern light having a sinusoidal light intensity distribution is projected after the three-dimensional measurement by the phase shift method is performed, but the present invention is not limited thereto, and for example, the pattern light having a non-sinusoidal light intensity distribution such as a rectangular wave or a triangular wave may be projected.

However, the measurement accuracy of projecting and three-dimensionally measuring the pattern light having the sinusoidal light intensity distribution is better than that of projecting and three-dimensionally measuring the pattern light having the non-sinusoidal light intensity distribution. Therefore, in order to improve the measurement accuracy, it is preferable to perform three-dimensional measurement by projecting pattern light having a sinusoidal light intensity distribution.

(e) In the above embodiment, the stripe pattern is projected onto the printed circuit board 1, and the solder paste 5 is three-dimensionally measured by the phase shift method. Not limited to this, for example, the three-dimensional measurement may be performed by another three-dimensional measurement method (pattern projection method) such as a spatial code method or a moire pattern method. However, when a small object to be measured such as the solder paste 5 is measured, a measurement method with high measurement accuracy such as a phase shift method is more preferably used.

(f) In the above embodiment, the printed circuit board 1 is irradiated with the slit light, and the height of the inspection range W (printed circuit board 1) is measured by the photo-cutting method, but the height measuring method of the inspection range W is not limited thereto.

For example, the following other measurement methods different from the light-section method may also be employed: the height measurement is performed by irradiating the laser pointer from the irradiation device 13 or irradiating a pattern light having a longer (thicker) cycle of stripes than the stripe pattern (the pattern light for three-dimensional measurement of the solder paste 5) irradiated from the projection device 14.

(g) The configuration of the second irradiation unit (projection unit) that irradiates the pattern light for three-dimensional measurement is not limited to the above-described embodiment.

For example, the projection apparatus 14 of the above embodiment is configured to use the grating plate 20 as a conversion unit that converts light from the light source 19 into a fringe pattern. Instead of the above, a liquid crystal optical shutter or the like may be employed as the switching unit.

The projection lens unit 21 of the projection apparatus 14 is configured by a double-sided telecentric lens (double-sided telecentric optical system) integrally including an incident-side lens and an exit-side lens. Not limited to this, an object-side telecentric lens (object-side telecentric optical system) may be used as the projection lens unit 21. Further, a structure without a telecentric structure may be employed.

In the projection apparatus 14 according to the above embodiment, the setting is made so that the sum condition is satisfied for the main surfaces of the printed circuit board 1, the lenticular plate 20, and the projection lens unit 21. Not limited to this, it may not necessarily be set to satisfy the schemer condition depending on the in-focus state of the fringe pattern in the entire projection range.

(h) The imaging means is not limited to the camera 15 of the above embodiment. For example, in the above embodiment, a CCD area sensor is used as the image pickup device 15a, but the present invention is not limited thereto, and for example, a CMOS area sensor or the like may be used.

The photographing lens unit 15b is formed of a double-sided telecentric lens (double-sided telecentric optical system). Not limited to this, an object-side telecentric lens (object-side telecentric optical system) may be used as the photographing lens unit 15 b. Further, a structure without a telecentric structure may be employed.

(i) In the above-described embodiment, in the step of associating the height position of the measuring head 12 with the solder paste 5 to be measured at the height position (step S4), in the example shown in fig. 6 and 7, the depth of field of the camera 15 including the entire focusing required range of the solder paste 5 is associated with each of the plurality of solder pastes 5, but the associating method is not limited to this.

For example, the following configuration is also possible: the height position of the measuring head 12 positioned is allocated so that the depth of field of the camera 15 does not overlap with the height range including all the solder pastes 5 in the inspection range W (the height range from the lower limit of the in-focus range of the solder paste 5 at the lowest position to the upper limit of the in-focus range of the solder paste 5 at the highest position).

In this configuration, since there may be a height position of the measuring head 12 where the solder paste 5 is not included in the depth of field of the camera 15, the measuring head 12 may not be stopped at the height position and three-dimensional measurement (solder measurement) may not be performed.

In the above configuration, there may be a case where a plurality of portions in the height direction of one solder paste 5 are measured by three-dimensional measurement (solder measurement) of different height positions, and therefore the method shown in the above embodiment is preferable in terms of achieving suppression of a decrease in measurement accuracy.

(j) In the above embodiment, when the "first height position" at which the measuring head 12 is positioned in the inspection range W is "solder measurement", it is determined whether the number of "solder measurements" required in the inspection range W is increased (step S5), and when it is determined that the number of "solder measurements" is not increased, the first "solder measurement" is performed at the "first height position" (step S6).

The moving order (measuring order) of the measuring head 12 is not limited to this. For example, the following may be configured: instead of performing the determination process and the like (steps S5 and S6), the measurement head 12 is moved from the "first height position" when it is positioned within the inspection range W to the lowermost height position or the uppermost height position among the plurality of height positions determined by the correlation (step S4), and the first "solder measurement" is performed.

(k) In the above embodiment, it is determined whether the "first height position" when the measuring head 12 is positioned within the inspection range W has moved to the lowest height position or the highest height position among the plurality of height positions to be moved when the height adjustment is required a plurality of times (step S8) to shorten the moving distance of the measuring head 12 (step S11), and the measuring head 12 is moved to the shorter side (steps S12 and S14).

The moving order (measuring order) of the measuring head 12 is not limited to this. For example, the following may be configured: the measuring head 12 is moved to the lowest height position or the highest height position, whichever is farther from the "initial height position".

(l) In the above embodiment, the entire measuring head 12 is configured to be moved in the Z-axis direction by the Z-axis moving mechanism 18. Instead, the camera 15 may be provided in the measurement head 12 so as to be movable relative to the irradiation device 13 and the projection device 14, and only the camera 15 may be movable in the Z-axis direction. In this case, the above-described association (step S4) is also performed in the relationship between the height position of the camera 15 and the solder paste 5 to be measured at the height position.

Description of the symbols

1 … printed circuit board, 3B … pad, 4 … resist film, 5 … soldering paste, 10 … substrate inspection device, 12 … measuring head, 13 … irradiation device, 14 … projection device, 15 … camera, 15a … shooting element, 18 … Z-axis moving mechanism, 40 … control device, 44 … image data storage device, 45 … operation result storage device, 46 … setting data storage device, K … shooting visual field, Q0-Q3 … depth of field, W (W1-W4) … inspection range.