JP5881235B2 - Three-dimensional measuring apparatus, three-dimensional measuring method and program - Google Patents

Description

  The present technology relates to a technology such as a three-dimensional measurement apparatus that three-dimensionally measures a measurement object using a phase shift method or the like.

  Conventionally, as a method for inspecting the quality of a measurement object such as a wiring board, a method for inspecting the quality of the measurement object by analyzing an image obtained by imaging the measurement object is used. In two-dimensional image analysis, since it is difficult to detect defects in the height direction such as chipping or dents in the measurement object, in recent years, the three-dimensional shape of the measurement object is measured by three-dimensional image analysis. Therefore, a method for inspecting the quality of a measurement object has been used.

  As a method for measuring the three-dimensional shape of a measurement object by image analysis, a phase shift method (time fringe analysis method), which is a kind of light cutting method, is widely used (see, for example, Patent Documents 1 and 2).

  The principle of the phase shift method will be described. In the phase shift method, first, fringes whose luminance changes in a sinusoidal shape are projected from the projection unit onto the measurement object. The phase of the fringe projected on the measurement object is shifted by a predetermined phase shift amount. The phase shift is repeated a plurality of times (minimum 3 times, usually 4 times or more) until the phase of the stripe moves by one period. When the phase of the fringes is shifted, the measurement object on which the fringes are projected is imaged by the imaging unit each time the phase is shifted. For example, when the phase shift amount is π / 2 [rad], the fringe phase is shifted to 0, π / 2, π, 3π / 2, and an image of the measurement object is captured at each phase. A total of four images are acquired.

In the case of four phase shifts, the luminance value of each pixel is obtained from four images and applied to the following equation (1) to obtain the phase φ (x, y) at the coordinates (x, y). Can be sought.
φ (x, y) = Tan ⁻¹ {I _{3π / 2} (x, y) −I _{π / 2} (x, y)} / {I ₀ (x, y) −I _π (x, y)} · (1)

Note that I ₀ (x, y), I _{π / 2} (x, y), I _π (x, y), and I _{3π / 2} (x, y) have phases of 0, π / 2, and π, respectively. This is the luminance value of the pixel located at the coordinates (x, y) in the case of 3π / 2.

  If the phase φ (x, y) can be obtained, the height information at each coordinate is obtained by the principle of triangulation based on the phase φ (x, y) to obtain the three-dimensional shape of the measurement object. it can.

JP 2010-175554 A (paragraphs [0003] to [0005]) JP 2009-204373 A (paragraphs [0023] to [0027])

  As shown on the right side of Expression (1), in the phase shift method, when obtaining the phase φ (x, y) at the coordinates (x, y), the luminance of the pixel located at the coordinates (x, y) It is necessary to find the difference in values.

  Here, for example, when the illumination of the projection unit is too dark, the difference in luminance value acquired from each of the four images is small, and therefore the phase φ (x, y) is accurately calculated by equation (1). I can't. As a result, there is a problem that the three-dimensional shape of the substrate cannot be measured accurately.

  On the other hand, when the illumination of the projection device is too bright, the luminance value of the pixel located in the bright portion of the stripe projected onto the measurement object exceeds the luminance value of 255, which is the maximum luminance value. The difference cannot be calculated. Therefore, there is a problem that the three-dimensional shape of the measurement object cannot be measured accurately as in the case where the illumination is dark.

  Here, the measurement object such as the wiring board may have different brightness for each part. For example, a portion where the wiring is concentrated under the resist applied on the substrate is darker than a portion where the wiring is not concentrated.

  In such a case, when a fringe is projected onto a bright part of the substrate (resist) with an appropriate illuminance, the illuminance is not appropriate for a dark part of the substrate (resist). Thus, the three-dimensional shape of the measurement object cannot be measured accurately. Similarly, when a fringe is projected onto a dark part of the substrate with an appropriate illuminance, the illuminance is not appropriate to an area where the substrate is bright. There is a problem that the shape cannot be measured.

  In view of the circumstances as described above, an object of the present technology is to appropriately measure a measurement object three-dimensionally when the measurement object has a plurality of regions having different brightness (colors). It is to provide a technology such as a three-dimensional measuring apparatus.

In order to achieve the above object, a three-dimensional measurement apparatus according to an embodiment of the present technology includes a projection unit, an imaging unit, and a control unit.
The projection unit has illumination capable of changing illuminance, and projects a stripe on a measurement object by light from the illumination.
The control unit causes the imaging unit to capture an image of the measurement object, acquires a brightness value from the captured image of the measurement object, and applies the measurement object to the measurement object based on the acquired brightness value. A plurality of inspection blocks are allocated to each of the assigned inspection blocks, and the measurement illuminance of the illumination is determined for each of the assigned inspection blocks, and the projection unit projects a stripe on the inspection block with the determined measurement illuminance. Then, a fringe image of the inspection block on which the fringes are projected is picked up by the imaging unit, and the measurement object is three-dimensionally measured based on the picked-up stripe images.

  In this three-dimensional measurement apparatus, an image of a measurement object is captured, a luminance value is acquired from the captured image of the measurement object, and a plurality of inspection blocks are provided for the measurement object based on the luminance value. Assigned. This makes it possible to assign an appropriate inspection block according to the brightness (color) of the measurement object. Therefore, when the measurement object has a plurality of regions having different brightness (colors), the measurement object can be appropriately measured three-dimensionally.

In the three-dimensional measurement apparatus, the measurement object may have a plurality of inspection objects on the measurement object.
In this case, when assigning the plurality of inspection blocks, the control unit acquires a luminance value of an inspection object surrounding area, which is an area around the inspection object, from the image of the measurement object, and the acquired inspection object A luminance attribute is set for each of the plurality of inspection objects based on a luminance value of a surrounding area, and the inspection block is assigned to each area of the measurement object where the inspection object having the same luminance attribute exists. Thus, the plurality of inspection blocks may be assigned to the measurement object.

  Thereby, a test | inspection block can be appropriately allocated according to the brightness (color) of a measurement object.

  In the three-dimensional measurement apparatus, when the control unit determines the measurement illuminance for each inspection block, the projection unit projects a stripe on the inspection block, and the inspection block on which the stripe is projected The fringe image is captured by the imaging unit, a luminance value is acquired from the fringe image, an error rate in three-dimensional measurement is calculated based on the luminance value, and the illuminance of the illumination is changed to calculate the error rate. It may be calculated for each illuminance, and the measured illuminance may be determined based on the error rate for each illuminance.

  In this three-dimensional measuring apparatus, an error rate for each illumination intensity is actually calculated for each inspection block. Based on the error rate for each illuminance, the measured illuminance for each inspection block is determined. Thereby, the measurement illumination intensity for every test | inspection block can be determined appropriately.

  In the three-dimensional measuring apparatus, when the control unit calculates the error rate, the control unit calculates a luminance value of an inspection object forming region that is an area where the inspection object is formed and a luminance value of the surrounding region of the inspection object. The error rate may be calculated based on the luminance value of the inspection object area and the luminance value of the surrounding area, which are obtained from the fringe image.

  In the three-dimensional measurement apparatus, when the error rate is calculated, the control unit determines an inspection object having a luminance attribute related to the inspection block among the plurality of inspection objects included in the inspection block. The error rate may be calculated based on a luminance value of the inspection object region and a luminance value of the surrounding region for an inspection object having a luminance attribute related to the inspection block.

  Thereby, an error rate can be appropriately calculated for each inspection block.

  The said three-dimensional measuring apparatus WHEREIN: The said control part may determine the illumination intensity that the said error rate becomes the minimum as the said measurement illumination intensity of the said test | inspection block.

  Thereby, when measuring a measurement object three-dimensionally, a fringe can be projected with respect to a test | inspection block with the appropriate measurement illumination intensity with a small error rate.

  In the three-dimensional measurement apparatus, when the control unit performs three-dimensional measurement of the measurement object based on the fringe image, a luminance value of an inspection object formation region that is an area where the inspection object is formed, and The brightness value of the surrounding area may be acquired from the striped image, and the measurement object may be measured three-dimensionally based on the brightness value of the inspection object area and the brightness value of the surrounding area.

  In the three-dimensional measurement apparatus, when the control unit performs three-dimensional measurement of the measurement object based on the fringe image, the control unit has an association with the inspection block among the plurality of inspection objects included in the inspection block. Determining the inspection object having the luminance attribute, and based on the luminance value of the inspection object area and the luminance value of the surrounding area for the inspection object having the luminance attribute related to the inspection block, An object may be measured three-dimensionally.

  Thereby, a measurement object can be appropriately measured three-dimensionally for each inspection block.

The three-dimensional measurement apparatus may include a storage unit that stores a table in which a luminance value of the measurement object and the measurement illuminance are associated with each other.
In this case, when determining the measurement illuminance for each inspection block, the control unit refers to the table stored in the storage unit and corresponds to the luminance value acquired from the image of the measurement object. The measured illuminance may be determined by determining the measured illuminance.

A three-dimensional measurement method according to an embodiment of the present technology includes capturing an image of a measurement object.
A luminance value is acquired from the imaged image of the measurement object.
Based on the acquired luminance value, a plurality of inspection blocks are assigned to the measurement object.
For each of the assigned inspection blocks, the measured illuminance of the illumination is determined.
Stripes are projected onto the inspection block at the determined measurement illuminance.
A stripe image of the inspection block on which the stripe is projected is captured.
The measurement object is three-dimensionally measured based on the captured stripe image.

A program according to an embodiment of the present technology causes a three-dimensional measurement apparatus to execute a step of capturing an image of a measurement target.
A step of acquiring a luminance value from the imaged measurement object is executed.
Based on the acquired luminance value, a step of assigning a plurality of inspection blocks to the measurement object is executed.
A step of determining a measurement illuminance of illumination is executed for each of the assigned inspection blocks.
A step of projecting a fringe on the inspection block is executed with the determined measurement illuminance.
The step of capturing a fringe image of the inspection block on which the fringes are projected is executed.
The step of three-dimensionally measuring the measurement object is executed based on the captured stripe image.

In the three-dimensional measurement method according to another aspect of the present technology, the first and second regions of the substrate having a first region and a second region having a color density different from the first region are provided. Obtaining the corresponding first and second color density information,
Measuring the first region by irradiating a checkered pattern with illuminance based on the first color density information,
Measurement is performed by irradiating the second region with a lattice pattern at an illuminance based on the second color density information.

  In the three-dimensional measurement method, the acquisition of the color density is performed by irradiating the first and second regions with a lattice pattern having a predetermined illuminance, and is set based on an error rate of the measurement result. Also good.

A three-dimensional measurement method according to still another embodiment of the present technology is directed to a first substrate region of a substrate having a first region and a second region having a color density different from that of the first region. And measure by irradiating the plaid with the first illuminance,
Measurement is performed by irradiating the second substrate region with lattice fringes at a second illuminance different from the first illuminance.

  As described above, according to the present technology, when the measurement object has a plurality of regions having different brightness (colors), the measurement object can be appropriately three-dimensionally measured. Techniques such as measuring devices can be provided.

It is a figure showing a three-dimensional measuring device concerning one embodiment of this art. It is a figure which shows an example of a board | substrate. It is a flowchart which shows a process when a some test | inspection block is allocated to the area | region on a board | substrate. It is a figure which shows the solder surrounding area | region set around the solder. It is a figure which shows the look-up table with which the average luminance value of the solder surrounding area and the luminance attribute were linked | related. It is a figure which shows an example when the some test | inspection block is allocated with respect to the area | region on a board | substrate. It is a figure which shows the other example when the some test | inspection block is allocated with respect to the area | region on a board | substrate. It is a figure which shows another example when a some test | inspection block is allocated with respect to the area | region on a board | substrate. It is a figure which shows the comparative example about inspection block allocation, and is a figure which shows a mode when the inspection block is allocated with respect to the area | region on a board | substrate, without considering the brightness (color) of a board | substrate (resist). . It is a flowchart which shows a process when the measurement illumination intensity in three-dimensional measurement is determined for every test | inspection block. It is a figure which shows the irradiation state of a stripe It is a flowchart which shows a process when an error rate is calculated. It is a figure which shows an example of the look-up table in which the test | inspection block and the measurement illumination intensity were linked | related. It is a flowchart which shows a process when a board | substrate is measured three-dimensionally. It is a figure which shows the look-up table in which the average brightness | luminance value of the solder surrounding area, the brightness | luminance attribute, and the measurement illumination intensity were linked | related.

<First Embodiment>
Hereinafter, embodiments of the present technology will be described with reference to the drawings.
FIG. 1 is a diagram illustrating a three-dimensional measurement apparatus 100 according to an embodiment of the present technology. As shown in FIG. 1, the three-dimensional measurement apparatus 100 includes a stage 10, a stage moving mechanism 11, an illumination unit 14, an imaging unit 15, a control unit 16, a storage unit 17, a display unit 18, and an input. A unit 19 and a projection unit 20 are provided.

  In the description of the present embodiment, as an example of the measurement object 1 that is three-dimensionally measured by the three-dimensional measurement apparatus 100, the substrate 1 on which the solder 2 (inspection object) for soldering the mounted component is formed is taken as an example. (See FIG. 2). The solder 2 is formed on the substrate 1 by, for example, a cream solder printer. The user uses the three-dimensional measuring apparatus 100 to three-dimensionally measure the substrate 1 and inspects the printing state of the solder 2 formed on the substrate 1.

  The substrate 1 is placed on the stage 10. The stage moving mechanism 11 is electrically connected to the control unit 16 and moves the stage 10 in the XYZ directions in accordance with a drive signal from the control unit 16.

  The projection unit 20 includes a light source 21 as illumination that can change illuminance, a condensing lens 22 that condenses light from the light source 21, a diffraction grating 23 that diffracts light collected by the condensing lens 22, And a projection lens 24 that projects the light diffracted by the diffraction grating 23 onto the substrate 1.

  Examples of the light source 21 include a halogen lamp, a xenon lamp, a mercury lamp, and an LED (Light Emitting Diode), but the type of the light source 21 is not particularly limited. The light source 21 is electrically connected to the illuminance adjustment mechanism 25. The illuminance adjustment mechanism 25 adjusts the illuminance of the light source 21 under the control of the control unit 16.

  The diffraction grating 23 has a plurality of slits, diffracts light from the light source 21, and projects a fringe whose luminance changes in a sine wave shape onto the substrate 1. The diffraction grating 23 is provided with a grating moving mechanism 26 that moves the diffraction grating 23 in a direction orthogonal to the direction in which the slits are formed. The grating moving mechanism 26 moves the diffraction grating 23 under the control of the control unit 16 to shift the phase of the fringes projected on the substrate 1. In place of the diffraction grating 23 and the grating moving mechanism 26, a liquid crystal grating or the like that displays a lattice-like stripe pattern may be used.

  The illumination unit 14 irradiates the substrate 1 with light. The illumination unit 14 includes, for example, two illuminations of an upper illumination 12 and a lower illumination 13 having an annular shape.

  The imaging unit 15 includes an imaging element such as a CCD (Charge Coupled Device) sensor and a CMOS (Complementary Metal Oxide Semiconductor) sensor, and an optical system such as an imaging lens that forms an image of light from the substrate 1 on the imaging surface of the imaging element. including. The imaging unit 15 images the substrate 1 on which the sine wave-like stripes are projected by the projection unit 20 in order to measure the substrate 1 (solder 2) three-dimensionally. The imaging unit 15 captures an image of the entire substrate 1 in a state where the substrate 1 is illuminated by the illumination unit 14.

  The display unit 18 is configured by, for example, a liquid crystal display or the like, and displays a three-dimensional image or the like of the substrate 1 under the control of the control unit 16. The input unit 19 includes a keyboard, a mouse, a touch panel, and the like, and inputs instructions from the user.

  The storage unit 17 includes a non-volatile memory such as a ROM (Read Only Memory) in which various programs necessary for the processing of the three-dimensional measuring apparatus 100 are stored, and a RAM (Random Access memory) used as a work area of the control unit 16. ) And other volatile memories.

  The control unit 16 is configured by, for example, a CPU (Central Processing Unit), and comprehensively controls the three-dimensional measurement apparatus 100 based on various programs stored in the storage unit 17. For example, the control unit 16 controls the illuminance adjustment mechanism 25 to adjust the illuminance of the projection unit 20 or controls the lattice movement mechanism 26 to shift the phase of the stripes projected on the substrate 1. In addition, the imaging unit 15 is controlled to capture an image of the substrate 1 on which the fringes are projected, or the substrate 1 is three-dimensionally measured by the phase shift method based on the captured image. The control of the control unit 16 will be described in detail later.

  FIG. 2 is a diagram illustrating an example of the substrate 1. As shown in FIG. 2, a plurality of solders 2 are formed on the substrate 1. The plurality of solders 2 are respectively formed on the pads. On the substrate 1, for example, a solder resist (hereinafter simply referred to as “resist”) is formed over the entire area of the substrate 1 except for the portion where the solder 2 is formed.

  In the example illustrated in FIG. 2, the substrate 1 has a plurality of regions with different brightness (color). For example, a portion where the wiring is concentrated under the resist is darker than a portion where the wiring is not concentrated. In the following description, a region where the substrate 1 (resist) is dark due to the concentration of wiring is called a dark region, and a region where the wiring is not concentrated and the substrate 1 (resist) is bright is described. This is called a region.

[Description of operation]
Next, processing of the control unit 16 of the three-dimensional measuring apparatus 100 will be described.

“Process when inspection block 4 is allocated”
First, processing when a plurality of inspection blocks 4 are assigned to an area on the substrate 1 will be described.

  FIG. 3 is a flowchart showing processing when a plurality of inspection blocks 4 are assigned to an area on the substrate 1.

  First, the control unit 16 of the three-dimensional measurement apparatus 100 controls the stage moving mechanism 11 to move the stage 10 to the receiving position of the substrate 1. And the control part 16 receives the board | substrate 1 from the board | substrate 1 delivery apparatus (not shown), moves the stage 10, and moves the board | substrate 1 to an imaging position.

  Next, the control unit 16 controls the illumination unit 14 to cause the illumination unit 14 to emit light and irradiate the substrate 1 with light. And the control part 16 controls the imaging part 15, and images the whole board | substrate 1 by the imaging part 15 (step 101). At this time, the control unit 16 may image the entire substrate 1 at a time by the imaging unit 15, or the substrate 1 is moved to the region by the imaging unit 15 while moving the substrate 1 in the XY direction by the stage 10 moving mechanism. You may image the whole board | substrate 1 by imaging for every. Thereby, the control unit 16 acquires information on the entire image of the substrate 1.

  When the information of the entire image of the board 1 is acquired, the control unit 16 next acquires the luminance value of the solder surrounding area 3b set around the solder 2 for each of the plurality of solders 2 (step 102).

  FIG. 4 is a diagram showing a solder surrounding area 3 b set around the solder 2. As shown in FIG. 4, a solder surrounding area 3 b is set around the solder 2. In the present specification, a region where the solder 2 (pad) is formed on the substrate 1 is referred to as a solder formation region 3a, and a region set around the solder formation region 3a is referred to as a solder peripheral region 3b.

  The control unit 16 acquires the luminance value from the solder surrounding area 3b as shown in FIG. Next, the control unit 16 calculates the average value of the luminance values of the solder surrounding area 3b (step 103). Thereby, the control unit 16 can recognize how bright the substrate 1 (resist) around the solder 2 is. In the example shown in FIG. 4, an example in which the shape of the solder surrounding region 3b is rectangular is shown, but the shape of the solder surrounding region 3b is not particularly limited.

  After calculating the average value of the luminance values of the solder surrounding area 3b, the control unit 16 next sets the luminance attribute for each of the plurality of solders 2 based on the average value of the luminance values (step 104).

  The relationship between the average luminance value of the solder surrounding area 3b and the luminance attribute will be described. FIG. 5 is a diagram showing a look-up table in which the average luminance value of the solder surrounding area 3b is associated with the luminance attribute. This lookup table is stored in the storage unit 17.

  As shown in FIG. 5, the average luminance value of the solder surrounding area 3b is classified into five levels of 0 to 50, 51 to 101, 102 to 152, 153 to 203, and 204 to 255. The luminance attributes 1, 2, 3, 4, and 5 are sequentially associated with the average luminance values 0 to 50, 51 to 101, 102 to 152, 153 to 203, and 204 to 255, respectively.

  FIG. 5 shows a case where the average luminance value of the solder peripheral region 3b is classified into five levels. However, the average luminance value of the solder peripheral region 3b is classified into two levels to four levels, or six levels or more. May be. As the number of steps of the average luminance value of the solder surrounding area 3b increases, the number of inspection blocks 4 (see FIG. 6) assigned to one substrate 1 increases.

  In step 104, the control unit 16 refers to this lookup table and sets a luminance attribute for each of the plurality of solders 2. For example, in the example shown in FIG. 4, it is assumed that the average brightness value of the resist in the solder peripheral region 3b is 30 for each of the plurality of solders 2 in the dark region. In this case, the luminance attribute 1 is set for each of the plurality of solders 2 in the dark region. Further, for example, in the example shown in FIG. 4, it is assumed that the average luminance value of the resist in the solder peripheral region 3 b is 155 for the plurality of solders 2 in the bright region. In this case, the luminance attribute 4 is set for each of the plurality of solders 2 in the bright region.

  When the luminance attribute is set for each of the plurality of solders 2, the control unit 16 next selects the luminance attribute to which the inspection block 4 should be assigned (step 105). In step 105, for example, the luminance attributes are selected in the order of luminance attribute 1, luminance attribute 2, luminance attribute 3, luminance attribute 4, and luminance attribute 5.

  In addition, the order of inspection block 4 allocation is not limited to this. For example, the order of luminance attribute 5, luminance attribute 4, luminance attribute 3, luminance attribute 2, and luminance attribute 1 may be in order, or may be random. When there is a luminance attribute that is not used when the control unit 16 sets the luminance attribute for the solder 2 in step 104, the control unit 16 does not select the luminance attribute in step 105. .

  For example, in the example shown in FIG. 4, as described above, the luminance attribute 1 is set for each of the plurality of solders 2 in the dark region, and the luminance attribute 4 is set for each of the plurality of solders 2 in the bright region. Assume that it is set. In this case, for example, the luminance attribute value to which the inspection block 4 is to be assigned is selected in the order of the luminance attribute 1 and the luminance attribute 4, or the order of the luminance attribute 4 and the luminance attribute 1. In this case, in step 105, the luminance attributes 2, 3, and 5 are not selected.

  When the control unit 16 selects the luminance attribute to which the inspection block 4 is assigned, the control unit 16 assigns the inspection block 4 to the area on the substrate 1 where the solder 2 having the selected luminance attribute is present (step 106). With reference to FIG. 6, the inspection block 4 has a size corresponding to the imaging field of the imaging unit 15.

  In step 106, first, the control unit 16 reads out the position coordinate information and size information of the plurality of solders 2 having the luminance attribute selected at that time from the storage unit 17. The position coordinate information and the size information of the solder 2 may be stored in advance in the storage unit 17 or calculated by the control unit 16 based on the information of the entire image of the substrate 1 captured in step 101. May be.

  Then, the control unit 16 determines whether or not the plurality of solders 2 having the luminance attribute selected at that time are within the imaging field of the imaging unit 15. That is, the control unit 16 determines whether or not the plurality of solders 2 having the luminance attribute selected at that time can be accommodated in one inspection block 4.

  When a plurality of solders 2 having the selected luminance attribute can be accommodated in one imaging field of view, the plurality of solders 2 having the luminance attribute are included in one inspection block 4 so as to be included in one inspection block 4. The inspection block 4 is assigned to the area.

  On the other hand, when the plurality of solders 2 having the luminance attribute selected at that time do not fit in the imaging field of the imaging unit 15, that is, when the plurality of solders 2 do not fit in one inspection block 4, the control unit 16 A plurality of inspection blocks 4 are assigned to an area on the substrate 1 where the plurality of solders 2 exist. At this time, the control unit 16 assigns the inspection block 4 to the area on the substrate 1 so that the number of inspection blocks 4 is minimized based on the coordinate information of the solder 2 and the size information. Further, in this case, the control unit 16 moves the substrate 1 in the XY direction so that the amount of movement of the substrate 1 in the XY direction is minimized when the substrate 1 is imaged in units of the inspection block 4. The inspection block 4 is assigned to the area above 1.

  When the inspection block 4 is assigned to the area on the substrate 1 where the solder 2 having the luminance attribute selected at that time is present, the control unit 16 next assigns the inspection block 4 to all the solders 2. It is determined whether the assignment has been completed (step 107). If not completed (NO in step 107), the control unit 16 returns to step 105, and again selects a luminance attribute to which the inspection block 4 should be assigned. Then, the control unit 16 assigns the inspection block 4 to the solder 2 having the luminance attribute selected at that time (step 106).

  By such processing, one or a plurality of areas for the area on the substrate 1 exist for each area where the solder 2 having the same luminance attribute (solder 2 in which the average luminance value of the solder surrounding area 3b is in the same range) exists. Test block 4 is assigned. That is, one or a plurality of inspection blocks 4 are assigned for each brightness (color) of the substrate 1 (resist).

  FIG. 6 is a diagram illustrating an example when a plurality of inspection blocks 4 are assigned to an area on the substrate 1. A process when the inspection block 4 as shown in FIG. 6 is assigned to an area on the substrate 1 will be specifically described.

  As described above, it is assumed that the average luminance value of the solder peripheral region 3b is 30 for the plurality of solders 2 in the dark region, and the luminance attribute 1 is set for each of the plurality of solders 2 in the dark region. Further, it is assumed that the average luminance value of the resist in the solder peripheral region 3b is 155 for the plurality of solders 2 in the bright region, and the luminance attribute 4 is set for each of the plurality of solders 2 in the bright region. In step 105, it is assumed that the luminance attribute 1 is selected as the luminance attribute to which the inspection block 4 is to be assigned.

  In this case, the control unit 16 assigns the inspection block 4 to the area on the substrate 1 where the plurality of solders 2 in the dark area having the luminance attribute 1 exist (step 106). At this time, based on the coordinate information of the solder 2 and the size information, the control unit 16 causes the plurality of solders 2 in the dark region having the luminance attribute 1 to be captured by the imaging field 15 (one inspection block 4). ). In FIG. 6, since the plurality of solders 2 in the dark region having the luminance attribute 1 are within the imaging field of the imaging unit 15, it is determined that the plurality of solders 2 in the dark region are within the imaging field of the imaging unit 15. . In this case, as shown in FIG. 6, the control unit 16 assigns the inspection block 4a (see the solid line) to the area on the substrate 1 where the plurality of solders 2 exist in the dark area.

  Next, the control unit 16 determines whether or not the inspection block 4 is assigned to all the solders 2 (step 107). In this case, since the solder 2 to which the inspection block 4 is not yet assigned remains (NO in Step 107), the control unit 16 returns to Step 105.

  In step 105, the luminance attribute 4 is selected as the luminance attribute to which the inspection block 4 is assigned. Next, the control unit 16 assigns the inspection block 4 to the area on the substrate 1 where the plurality of solders 2 in the bright area having the luminance attribute 4 exist (step 106).

  At this time, based on the coordinate information of the solder 2 and the size information, the control unit 16 causes the plurality of solders 2 in the bright region having the luminance attribute 4 to be captured by the imaging field 15 (one inspection block 4). ). In FIG. 6, since the plurality of solders 2 in the bright region having the luminance attribute 4 do not fit in the imaging field of the imaging unit 15, the control unit 16 determines that the plurality of solders 2 in the bright region are in the imaging field of view of the imaging unit 15. It is determined that it does not fit in.

  In this case, the control unit 16 assigns the plurality of inspection blocks 4 to the area on the substrate 1 where the plurality of solders 2 having the luminance attribute 4 exist. At this time, the control unit 16 assigns the plurality of inspection blocks 4 to the area on the substrate 1 so that the number of inspection blocks is minimized based on the coordinate information of the solder 2 and the size information. In this case, the control unit 16 also moves the substrate 1 so that the amount of movement of the substrate 1 in the XY direction is minimized when the substrate 1 is moved in the XY direction and the substrate 1 is imaged in units of inspection blocks. The inspection block 4 is assigned to the upper area.

  As a result, as shown in FIG. 6, the inspection block 4b (see the dotted line) and the inspection block 4c (one-dot chain line) are applied to the area on the substrate 1 where the plurality of solders 2 in the bright area having the luminance attribute 4 exist. Reference), inspection block 4d (refer to the two-dot chain line), and inspection block 4e (refer to the broken line) are allocated.

  Next, the control unit 16 determines whether or not the inspection block 4 is assigned to all the solders 2 (step 106). In this case, since the inspection block 4 is assigned to all the solders 2 (YES in step 106), the control unit 16 ends the process.

  FIG. 7 is a diagram illustrating another example when a plurality of inspection blocks 4 are assigned to an area on the substrate 1. In FIG. 7, compared with FIG. 6, the position of the solder 2 on the substrate 1 is the same, but the position of the dark region is different.

  A process when the inspection block 4 as shown in FIG. 7 is assigned will be described. The control unit 16 controls the imaging unit 15 and images the entire substrate by the imaging unit 15 (step 101). Next, the control unit 16 acquires information on the luminance value of the solder peripheral region 3b from the entire image of the substrate 1 (step 102), and calculates the average value of the luminance values of the solder peripheral region 3b for each of the plurality of solders 2. (Step 103).

  Next, the control unit 16 sets a luminance attribute for each of the plurality of solders 2 based on the average value of the luminance values of the solder surrounding area 3b (step 104). At this time, the control unit 16 refers to the lookup table shown in FIG. 5 and sets the brightness attribute of the resist for each of the plurality of solders 2.

  For example, in the example shown in FIG. 7, the average luminance value of the solder peripheral region 3 b is 30 for each of the plurality of solders 2 in the dark region, and the luminance attribute 1 is set for each of the plurality of solders 2 in the dark region. Suppose that it is set. In the example shown in FIG. 7, the average luminance value of the solder peripheral region 3b is 155 for each of the plurality of solders 2 in the bright region, and the luminance attribute 4 is set for each of the plurality of solders 2 in the bright region. Suppose that it is set.

  In step 105, it is assumed that the luminance attribute 1 is selected as the luminance attribute to which the inspection block 4 is to be assigned. In this case, based on the coordinate information of the solder 2 and the size information, the control unit 16 causes the plurality of solders 2 in the dark region having the luminance attribute 1 to be captured by the imaging field 15 (one inspection block 4). ).

  In FIG. 7, the plurality of solders 2 in the dark region having the luminance attribute 1 are within the imaging field of the imaging unit 15. In this case, as shown in FIG. 7, the control unit 16 assigns the inspection block 4f (see the broken line) to the area on the substrate 1 where the plurality of solders 2 exist in the dark area.

  Next, the control unit 16 returns to 105 and selects the luminance attribute 4 as the luminance attribute to which the inspection block 4 should be assigned. Then, based on the coordinate information of the solder 2 and the size information, the control unit 16 causes the plurality of solders 2 in the bright area having the luminance attribute 4 to be captured by the imaging unit 15 (one inspection block 4). It is determined whether it fits. In FIG. 7, the plurality of solders 2 in the bright area having the luminance attribute 4 do not fit in the imaging field of the imaging unit 15.

  In this case, based on the coordinate information of the solder 2 and the size information, the control unit 16 minimizes the number of inspection blocks 4 and minimizes the amount of movement of the substrate 1 in the XY direction. A plurality of inspection blocks 4 are assigned to the area on the substrate 1.

  As a result, as shown in FIG. 7, the inspection block 4g (see the dotted line) and the inspection block 4h (one-dot chain line) are applied to the area on the substrate 1 where the plurality of solders 2 in the bright area having the luminance attribute 4 exist. Reference) and inspection block 4i (refer to the two-dot chain line) are assigned.

  FIG. 8 is a diagram showing still another example when a plurality of inspection blocks 4 are assigned to the area on the substrate 1.

  A process when the inspection block 4 as shown in FIG. 8 is assigned will be described. The control unit 16 controls the imaging unit 15 and images the entire substrate by the imaging unit 15 (step 101). Next, the control unit 16 acquires information on the luminance value of the solder peripheral region 3b from the entire image of the substrate 1 (step 102), and calculates the average value of the luminance values of the solder peripheral region 3b for each of the plurality of solders 2. (Step 103).

  Next, the control unit 16 sets a luminance attribute for each of the plurality of solders 2 based on the average value of the luminance values of the solder surrounding area 3b (step 104). At this time, the control unit 16 refers to the lookup table shown in FIG. 5 and sets the brightness attribute of the resist for each of the plurality of solders 2.

  For example, in the example shown in FIG. 8, the average luminance value of the resist in the solder peripheral region 3b is 30 for each of the plurality of solders 2 in the dark region, and the luminance attribute for each of the plurality of solders 2 in the dark region. Assume that 1 is set. In the example shown in FIG. 8, the average luminance value of the resist in the solder peripheral region 3b is 155 for each of the plurality of solders 2 in the bright region, and the luminance attribute for each of the plurality of solders 2 in the bright region. Assume that 4 is set.

  In step 105, it is assumed that the luminance attribute 1 is selected as the luminance attribute to which the inspection block 4 is to be assigned. At this time, based on the coordinate information of the solder 2 and the size information, the control unit 16 causes the plurality of solders 2 in the dark region having the luminance attribute 1 to be captured by the imaging field 15 (one inspection block 4). ). In FIG. 8, the plurality of solders 2 in the dark region having the luminance attribute 1 do not fit in the imaging field of the imaging unit 15. In this case, based on the coordinate information of the solder 2 and the size information, the control unit 16 minimizes the number of inspection blocks 4 and minimizes the amount of movement of the substrate 1 in the XY direction. A plurality of inspection blocks 4 are assigned to the area on the substrate 1 (step 106).

  As a result, as shown in FIG. 8, the inspection block 4j (see the dotted line) and the inspection block 4k (see the alternate long and short dash line) are assigned to the region on the substrate 1 where the plurality of solders 2 included in the dark region are present. It is done.

  Next, the control unit 16 returns to Step 105 and selects the luminance attribute 4 as the luminance attribute to which the inspection block 4 should be assigned. Then, based on the coordinate information of the solder 2 and the size information, the control unit 16 places a plurality of solders 2 in the bright region having the luminance attribute 4 in the imaging field of view of the imaging unit 15 (one inspection block 4). Judge whether it fits. In FIG. 8, the plurality of solders 2 in the bright region having the luminance attribute 4 are not sized to fit in the imaging field of the imaging unit 15. In this case, based on the coordinate information of the solder 2 and the size information, the control unit 16 minimizes the number of inspection blocks 4 and minimizes the amount of movement of the substrate 1 in the XY direction. The inspection block 4 is assigned to the area on the substrate 1 (step 106).

  As a result, as shown in FIG. 8, the inspection block 4l (refer to the two-dot chain line) and the inspection block 4m (refer to the broken line) are assigned to the region on the substrate 1 where the plurality of solders 2 exist in the bright region. .

  For example, when the type of the substrate 1 to be three-dimensionally measured by the three-dimensional measuring apparatus 100 is changed, the inspection block 4 allocation process illustrated in FIG. 3 is executed on the first substrate 1 after the change. For the second and subsequent substrates 1 having the same configuration as the first substrate 1, the inspection block 4 assigned by the first substrate 1 is used.

  FIG. 9 is a diagram showing a comparative example of block allocation. When the inspection block 4 is allocated to an area on the substrate 1 without considering the brightness (color) of the substrate 1 (resist). It is a figure which shows a mode.

  In the example shown in FIG. 9, based on the coordinate information of the solder 2 and the size information, the board so that the number of inspection blocks 4 is minimized and the amount of movement of the board 1 in the XY direction is minimized. The inspection block 4 is assigned to the area above 1. In this example, the brightness (color) of the substrate 1 (resist) is not considered in the allocation of the inspection block 4.

  In the example illustrated in FIG. 9, the inspection blocks 4o, 4p, and 4q include the solder 2 in the bright region and the solder 2 in the dark region. In this case, when the stripe is projected onto the substrate 1 and the substrate 1 (solder 2) is measured three-dimensionally, if the stripe is projected with an appropriate illuminance on the bright area, the illuminance is Since the illuminance is not appropriate, the three-dimensional shape of the substrate 1 (solder 2) cannot be measured accurately in the dark region. Similarly, when a stripe is projected on a dark area with an appropriate illuminance, the illuminance is not appropriate for a bright area. Therefore, the substrate 1 (solder 2) is accurately three-dimensional in a bright part of the substrate 1. The shape cannot be measured.

  For example, in the inspection blocks 4o, 1p, and 1q, a stripe is projected with an appropriate illuminance on a bright area and imaged by the imaging unit 15, and then a stripe is projected with an appropriate illuminance on a dark area. It is also conceivable to take an image with the imaging unit 15. However, in this case, since it is necessary to project and image stripes by changing the illuminance in each of the inspection blocks 4o, 1p, and 1q, the inspection tact is delayed.

  On the other hand, in the present embodiment, the inspection block 4 can be appropriately allocated according to the brightness (color) of the substrate 1 (resist) as shown in FIGS. Thereby, it is possible to accurately measure the three-dimensional shape of the substrate 1 (solder 2) by determining an appropriate measurement illuminance for each inspection block 4, and projecting and imaging stripes on the block with the measurement illuminance. . Further, in the three-dimensional measurement, since the number of times of projection and imaging of fringes can be reduced as compared with the case where the projection and imaging of fringes are repeated with the same inspection block 4 with different illuminances, the inspection tact time is reduced. It can be prevented from becoming slow.

“Process when measurement illuminance is determined for each inspection block 4”
Next, a process when the measurement illuminance in the three-dimensional measurement is determined for each inspection block 4 will be described. FIG. 10 is a flowchart showing processing when the measurement illuminance in the three-dimensional measurement is determined for each inspection block 4.

  First, the control part 16 selects the test | inspection block 4 which projects a fringe among the some test | inspection blocks 4 (step 201). The order in which the inspection blocks 4 are selected is not particularly limited. For example, the inspection blocks 4 are selected so that the movement distance of the substrate 1 in the XY direction is the shortest.

  Next, the control unit 16 controls the stage 10 moving mechanism to move the position of the substrate 1 to a position where a stripe can be projected onto the selected inspection block 4. In the present embodiment, the substrate 1 is moved in the XY directions. However, the imaging unit 15 and the projection unit 20 may be moved in the XY directions. Alternatively, both the substrate 1 and the imaging unit 15 and the projection unit 20 may be moved in the XY directions.

  Next, the control unit 16 controls the illuminance adjustment mechanism 25 to set the illuminance of the light source 21 to an initial value (for example, 20) (step 203). When the illuminance of the light source 21 is set to an initial value, the projection unit 20 projects a stripe onto the inspection block 4 of the substrate 1. Next, the control unit 16 images the inspection block 4 on which the fringes are projected by the imaging unit 15 (step 204).

  Next, the control unit 16 controls the grating moving mechanism 26 to move the diffraction grating 23, thereby shifting the phase of the fringes projected onto the inspection block 4 by π / 2 [rad] (step 205). . When the phase of the fringes is shifted, the control unit 16 next determines whether four images are captured with the same illuminance (step 206).

  When four images are not captured with the same illuminance (NO in step 206), the control unit 16 returns to step 204 and captures the inspection block 4 on which the stripes are projected. As a result, a total of four images with the same illuminance and different fringe phases are captured.

  FIG. 11 is a diagram illustrating a stripe irradiation state. FIG. 11 shows the irradiation state of the stripes when the phase of the stripes is 0, π / 2, π, 3π / 2 in order from the left side.

  Referring to FIG. 10 again, when the fourth image is captured with the same illuminance (YES in step 206), the control unit 16 uses the phase shift method based on the acquired four images. The height at each pixel of the image is calculated (step 207).

In this case, the control unit 16 determines the luminance value I ₀ of each pixel (each coordinate (x, y)) in the solder formation region 3a and the solder surrounding region 3b (see FIG. 4) from the four images of the inspection block 4. I _{π / 2} , I _π , and I _{3π / 2} are acquired. And the control part 16 calculates the phase (phi) (x, y) in each pixel in the solder formation area | region 3a and the solder surrounding area | region 3b by applying the following formula | equation (2). Then, the control unit 16 calculates the height of each pixel using the principle of triangulation based on the calculated phase φ (x, y) at each pixel.

φ (x, y) = Tan ⁻¹ {I _{3π / 2} (x, y) −I _{π / 2} (x, y)} / {I ₀ (x, y) −I _π (x, y)} · (2)
The formula (2) is the same as the above formula (1), and I ₀ (x, y), I _{π / 2} (x, y), I _π (x, y), I _{3π / 2} (X, y) is a luminance value of each pixel (each coordinate) when the phase of the stripe is 0, π / 2, π, 3π / 2, respectively.

  Here, when converting the luminance value to the height, under a predetermined condition, the pixel cannot be converted in height based on the phase φ (x, y), and the pixel is regarded as an error. .

  Once the luminance value of each pixel is converted to the height of each coordinate, the control unit 16 then calculates the ratio (error rate) of the pixels whose height cannot be converted (step 208).

  Note that details on the condition that the conversion to the height based on the phase φ (x, y) is impossible and the calculation method of the ratio (error rate) of the pixels that cannot be converted to the height will be described later. To do.

  After calculating the error rate, the control unit 16 next determines whether or not the current illuminance of the projection unit 20 is the maximum value (for example, 240) (step 209). When the illuminance is not the maximum value (NO in Step 209), the control unit 16 changes the illuminance (for example, illuminance +20) (Step 210).

  And the control part 16 returns to step 204 again, images the test | inspection block 4 with which the stripe was projected with the changed illumination intensity, and images four images again. When four images are captured, the height at each pixel (each coordinate) is calculated by the phase shift method, and the error rate at that illuminance is calculated. This series of processing is repeated until the illuminance of the projection unit 20 becomes maximum.

  When the illuminance is the maximum value (YES in Step 209), the control unit 16 determines the measurement illuminance for three-dimensionally measuring the target inspection block 4 based on the error rate at each illuminance ( Step 211). In this case, for example, the illuminance that minimizes the error rate is determined as the measured illuminance.

  Next, the control unit 16 determines whether or not the measurement illuminance has been determined in all the inspection blocks 4 (step 212). When the inspection block 4 for which the measurement illuminance is not determined remains (NO in step 212), the control unit 16 returns to step 201 and selects the inspection block 4 on which the fringes are projected again.

  On the other hand, when the measurement illuminance is determined in all the inspection blocks 4 (YES in step 212), the control unit 16 ends the process. In this way, for each of the plurality of inspection blocks 4, the optimum measurement illuminance when the substrate 1 is three-dimensionally measured is determined.

  The process for determining the measurement illuminance for each inspection block 4 shown in FIG. 10 is performed on the first substrate 1 after the change, for example, when the type of the substrate 1 to be three-dimensionally measured by the three-dimensional measuring apparatus 100 is changed. It is executed against. For the second and subsequent substrates 1 having the same configuration as that of the first substrate 1, the measured illuminance determined by the first substrate 1 is used.

  In the description of FIG. 10, the case where the initial value of the illuminance of the projection unit 20 is set to 20 and the illuminance is changed by +20 is changed to the maximum value 240. On the other hand, a method is used in which the repetition step width is initially set large (for example, +50), and the initial value and maximum value of illuminance are reset near the error rate to reduce the step width. (For example, + 50 → + 10 → + 1). Thereby, measurement illuminance can be determined efficiently and in detail.

"Error rate calculation method"
Next, as described in Steps 207 and 208 of FIG. 10, the condition that the conversion to the height based on the phase φ (x, y) is impossible (error) and the pixel that cannot be converted to the height are made. A method for calculating the ratio (error rate) will be described in detail.

  FIG. 12 is a flowchart illustrating a process when the error rate is calculated.

First, the control unit 16 picks up the luminance value I ₀ (x, y) of each pixel (each coordinate (x, y)) from four images of the inspection block 4 that are captured with the same illuminance and have different fringe phases. , I _{π / 2} (x, y), I _π (x, y), and I _{3π / 2} (x, y) are acquired (step 301). In this case, the control unit 16 acquires the luminance value of each pixel not from the entire image of the inspection block 4 but from the solder formation region 3a and the solder surrounding region 3b (see FIG. 4) in the inspection block 4.

At this time, the control unit 16 sets the solder formation area 3a and the solder surrounding area 3b of the solder 2 having a luminance attribute related to the inspection block 4 (the luminance attribute used when the inspection block 4 is assigned). Luminance values I ₀ , I _{π / 2} , I _π , and I _{3π / 2} are used. On the other hand, the control unit 16 includes a solder formation region 3a and a solder surrounding region for the solder 2 having a luminance attribute that is not related to the inspection block 4 (a luminance attribute that is not used when the inspection block 4 is assigned). The luminance values I ₀ , I _{π / 2} , I _π , and I _{3π / 2} of 3b are not used.

For example, inspection blocks 4b, 4c, and 4d shown in FIG. 6 include solder 2 in a bright area having luminance attribute 4 and solder 2 in a dark area having luminance attribute 1. In this case, when the control unit 16 calculates the error rate for each illuminance of the inspection blocks 4b, 4c, and 4d, the luminance of the solder formation region 3a and the solder surrounding region 3b for the solder 2 in the bright region having the luminance attribute 4 The values I ₀ , I _{π / 2} , I _π , I _{3π / 2} are used. On the other hand, the control unit 16 does not use the brightness values I ₀ , I _{π / 2} , I _π , and I _{3π / 2} of the solder formation region 3a and the solder surrounding region 3b for the solder 2 in the dark region having the luminance attribute 1. .

On the other hand, the inspection block 4 a shown in FIG. 6 includes the solder 2 in the dark area having the luminance attribute 1 and a part of the solder 2 in the bright area having the luminance attribute 4. In this case, when the control unit 16 calculates the error rate for each illuminance of the inspection block 4a, the luminance value I ₀ of the solder formation region 3a and the solder surrounding region 3b for the solder 2 in the dark region having the luminance attribute 1, I _{π / 2} , I _π , and I _{3π / 2} are used. On the other hand, the control unit 16 does not use the brightness values I ₀ , I _{π / 2} , I _π , and I _{3π / 2} of the solder formation region 3a and the solder surrounding region 3b for the solder 2 in the bright region having the luminance attribute 4. .

  By such processing, the error rate can be appropriately calculated for each inspection block 4. In the description here, the substrate 1 shown in FIG. 6 has been described as an example, but the same applies to the substrate 1 shown in FIG. 7 and the substrate 1 shown in FIG.

Referring to FIG. 12 again, when the luminance value is acquired from the solder formation region 3a and the solder surrounding region 3b, the control unit 16 next, the luminance corresponding to one pixel in the solder formation region 3a and the solder surrounding region 3b. The values I ₀ , I _{π / 2} , I _π , and I _{3π / 2} are input (step 302).

Next, the control unit 16 determines the luminance value I ₀ of the image (first sheet) when the phase of the stripe is 0 and the phase of the stripe for one pixel in the solder formation region 3a and the solder surrounding region 3b. The absolute value of the difference from the luminance value I _π of the image (third image) when π is calculated (step 303). Similarly, the control unit 16 sets the luminance value I _{π / 2} of the image (second sheet) when the phase of the stripe is π / 2 for one pixel in the solder formation region 3a and the solder surrounding region 3b. Then, the absolute value of the difference from the luminance value I _{3π / 2} of the image (fourth image) when the fringe phase is 3π / 2 is calculated (step 304).

Next, the control unit 16 determines the larger of the two absolute values of the absolute value of the difference between the luminance values I ₀ and I _π and the absolute value of the difference between the luminance values I _{π / 2} and I _{3π / 2} . It is determined whether the value is less than the first threshold Th1 (step 305). The first threshold Th1 is, for example, about 10-20.

  When the larger value of the two absolute values is less than the first threshold Th1 (YES in Step 305), the control unit 16 cannot convert the pixel into a height by the phase shift method ( Error) (step 308). Then, the control unit 16 proceeds to the next step 309.

  That is, when the larger one of the two absolute values is too small, the value of the phase φ cannot be accurately calculated when the phase φ is calculated by the above equation (2). Therefore, in the pixel, the conversion in the height direction is disabled (error).

  For example, when a stripe is projected onto the inspection block 4 and the illuminance of the light source 21 is too small and the stripe projected onto the inspection block 4 is too dark, the larger of the two absolute values is used. The value is less than the first threshold Th1 (for example, 15). In such a case, conversion in the height direction becomes impossible (error).

On the other hand, when the larger one of the two absolute values is equal to or greater than the first threshold Th1 (NO in step 305), the control unit 16 proceeds to the next step 306. In step 306, the control unit 16 selects one of the four luminance values I ₀ (x, y), I _{π / 2} (x, y), I _π (x, y), and I _{3π / 2} (x, y). , It is determined whether at least one value is greater than or equal to the second threshold Th2. The second threshold Th2 is, for example, 255.

  When at least one of the four luminance values is equal to or greater than the second threshold Th2 (YES in step 306), the control unit 16 disables conversion to height based on the luminance value (error) ( Step 308). Then, the control unit 16 proceeds to the next step 309.

  That is, when at least one of the four luminance values is 255 or more, the upper limit of the luminance value is exceeded. Therefore, when calculating the phase φ by the above equation (2), the value of the phase φ is accurately calculated. Can not do it. Therefore, in the pixel, the conversion in the height direction is disabled (error).

  On the other hand, when all the four luminance values are less than the second threshold Th2 (NO in step 306), the control unit 16 allows conversion to height based on the luminance value (step 307), and the next step 309. Proceed to

  In step 309, the control unit 16 causes the solder formation region 3 a and the solder surrounding region 3 b of the solder 2 having the luminance attribute related to the inspection block 4 (the luminance attribute used when the inspection block 4 is assigned). It is determined whether or not it is determined whether or not conversion in the height direction is possible for all of the pixels.

  When the undetermined pixel remains in the solder formation region 3a and the solder surrounding region 3b (NO in step 309), the control unit 16 returns to step 302 and repeats the processing in steps 302 to 309.

  On the other hand, when the determination is completed for all the pixels included in the solder formation region 3a and the solder surrounding region 3b (YES in Step 309), the control unit 16 determines the pixels included in the solder formation region 3a and the solder surrounding region 3b. Is calculated (step 310). In this case, the control unit 16 divides the number of pixels having an error in the solder formation region 3a and the solder peripheral region 3b by the total number of pixels in the solder formation region 3a and the solder peripheral region 3b, thereby obtaining an error rate. Can be calculated.

  Steps 301 to 310 are executed whenever the illuminance of the light source 21 of the projection unit 20 is changed (see FIG. 10). Thereby, the error rate is calculated for each illuminance of the light source 21. Further, the error rate for each illuminance of the light source 21 is calculated for each inspection block 4 (see FIG. 10).

  For example, in the inspection block 4a (see FIG. 6), inspection block 4f (see FIG. 7), inspection blocks 4j and 1k (see FIG. 8) assigned to the dark area on the substrate 1, the illuminance of the light source 21 is 150. In this case, it is assumed that the error rate is minimum at 10%. In this case, the measurement illuminance is 150 in the inspection blocks 4a, 1f, 1j, and 1k.

  Further, for example, in the inspection blocks 4b to 1e (see FIG. 6), the inspection blocks 4g to 1i (see FIG. 7), and the inspection blocks 4l and 1m (see FIG. 8) assigned to the bright area on the substrate 1, It is assumed that when the illuminance of the light source 21 is 10, the error rate is 5% and the minimum. In this case, the measurement illuminance is 10 in the inspection blocks 4b to 1e, 1g to 1i, 1l, and 1m.

  When the measurement illuminance at each inspection block 4 is determined, the control unit 16 stores the inspection block 4 and the measurement illuminance in association with each other in the storage unit 17.

  FIG. 13 is a diagram illustrating an example of a lookup table in which the inspection block 4 and the measured illuminance are associated with each other. In the example illustrated in FIG. 13, a state when the measurement illuminance is associated with each inspection block 4 of the substrate 1 illustrated in FIG. 6 is illustrated. As shown in FIG. 6, the measurement illuminance 150 is associated with the inspection block 4a, and the measurement illuminance 10 is associated with the inspection blocks 4b to 1e. When the measurement illuminance is determined, the measurement illuminance may be displayed on the display unit 18. Thereby, the user can visually recognize the optimum measurement illuminance in each inspection block 4.

“Process when measuring substrate 1 three-dimensionally”
Next, after the measurement illuminance is determined for each inspection block 4, a process when the substrate 1 (solder 2) is three-dimensionally measured by projecting stripes onto the inspection block 4 with the measurement illuminance will be described.

  FIG. 14 is a flowchart showing processing when the substrate 1 is three-dimensionally measured. First, the control unit 16 selects an inspection block 4 on which a fringe is projected from among the plurality of inspection blocks 4 (step 401). The order in which the inspection blocks 4 are selected is not particularly limited. For example, the inspection blocks 4 are selected so that the movement distance of the substrate 1 in the XY direction is the shortest.

  Next, the control unit 16 controls the stage 10 moving mechanism to move the position of the substrate 1 to a position where a stripe can be projected onto the selected inspection block 4 (step 402). Note that instead of the substrate 1 being moved in the XY directions, the imaging unit 15 and the projection unit 20 may be moved in the XY directions. Alternatively, both the substrate 1 and the imaging unit 15 and the projection unit 20 may be moved in the XY directions.

  Next, the control part 16 reads the measurement illumination intensity corresponding to the test | inspection block 4 from the memory | storage part 17 (step 403). As described above, the inspection block 4 and the measured illuminance are stored in association with the storage unit 17 when the measured illuminance is determined (see FIG. 13). Can be read out. And the control part 16 makes the light source 21 light-emit with the measurement illumination intensity read from the memory | storage part 17 (step 403). Thereby, the fringes are projected onto the inspection block 4 with an appropriate illuminance corresponding to the brightness (color) of the substrate 1 (resist) with a low error rate.

  When the stripe is projected, the control unit 16 images the inspection block 4 on which the stripe is projected by the imaging unit 15 (step 404). Next, the control unit 16 controls the grating moving mechanism 26 to move the diffraction grating 23 to shift the phase of the fringes projected onto the inspection block 4 by π / 2 [rad] (step 405). . After shifting the fringe phase, the control unit 16 next determines whether four images having different fringe phases have been captured (step 406).

  When four images with different fringe phases are not captured (NO in step 406), the control unit 16 returns to step 404 and images the inspection block 4 on which the fringes are projected. As a result, a total of four images with different fringe phases are captured.

  When the fourth image is captured (YES in step 406), the control unit 16 calculates the height at each pixel of the image by the phase shift method based on the acquired four images (step 406). Step 407).

In this case, the control unit 16 acquires the luminance values I ₀ , I _{π / 2} , I _π , and I _{3π / 2} of each pixel (each coordinate (x, y)) from the four images of the inspection block 4. And the control part 16 calculates phase (phi) (x, y) in each pixel by applying said Formula (2). Then, the control unit 16 calculates the height of each pixel using the principle of triangulation based on the calculated phase φ (x, y) at each pixel (step 407).

  In step 407, the control unit 16 acquires the luminance value of each pixel from the solder formation region 3a and the solder surrounding region 3b in the inspection block 4, and calculates the height in the solder formation region 3a and the solder surrounding region 3b. In this case, the control unit 16 has a solder formation area 3a and a solder surrounding area 3b for the solder 2 having a luminance attribute related to the inspection block 4 (the luminance attribute used when the inspection block 4 is assigned). The luminance value of each pixel is acquired from the above, and the height is calculated.

For example, inspection blocks 4b, 4c, and 4d shown in FIG. 6 include solder 2 in a bright area having luminance attribute 4 and solder 2 in a dark area having luminance attribute 1. When the control unit 16 three-dimensionally measures the inspection blocks 4b, 4c, and 4d, the luminance values I ₀ and I _{π /} of the solder formation region 3a and the solder surrounding region 3b for the solder 2 in the bright region having the luminance attribute 4 are measured. ₂ , I _π , I _{3π / 2} are used to calculate the heights of the solder formation region 3a and the solder surrounding region 3b. On the other hand, when the control unit 16 three-dimensionally measures the inspection blocks 4b, 4c, and 4d, the luminance values I ₀ and I of the solder formation region 3a and the solder surrounding region 3b for the solder 2 in the dark region having the luminance attribute 1 are measured. _{π / 2} , I _π , and I _{3π / 2} are not used.

On the other hand, the inspection block 4 a shown in FIG. 6 includes the solder 2 in the dark area having the luminance attribute 1 and a part of the solder 2 in the bright area having the luminance attribute 4. When the control unit 16 measures the inspection block 4a three-dimensionally, the luminance values I ₀ , I _{π / 2} , I _π of the solder forming region 3a and the solder surrounding region 3b for the solder 2 in the dark region having the luminance attribute 1 are measured. , I _{3π / 2} is used. On the other hand, when the control unit 16 measures the inspection block 4a three-dimensionally, the luminance values I ₀ , I _{π / 2} of the solder formation region 3a and the solder surrounding region 3b for the solder 2 in the bright region having the luminance attribute 4, I _π and I _{3π / 2} are not used.

  Thereby, it is possible to appropriately three-dimensionally measure a plurality of regions having different brightness (color) of the substrate 1 (resist).

  Next, the control unit 16 determines whether or not the three-dimensional measurement is completed in all the inspection blocks 4 (step 408). When the inspection block 4 for which the three-dimensional measurement is not completed remains (NO in Step 408), the control unit 16 returns to Step 401 and selects the inspection block 4 on which the fringes are projected again. A series of processing from step 401 to step 408 is executed until the three-dimensional measurement is completed in all the inspection blocks 4.

  When the three-dimensional measurement is executed for all the inspection blocks 4, for example, the control unit 16 combines the measurement results and displays the three-dimensional shape of the substrate 1 (solder 2) on the screen of the display unit 18. Also good. The user can inspect whether the shape of the solder 2 is an appropriate shape by visually recognizing the three-dimensional shape of the substrate 1 (solder 2). Further, the control unit 16 may display the amount of the solder 2 on the substrate 1 on the screen of the display unit 18. The user can inspect whether the amount of the solder 2 on the substrate 1 is an appropriate amount by visually recognizing the amount of the solder 2.

  By the processing shown in FIG. 13, stripes are projected on all the inspection blocks 4 with the optimum measurement illuminance (measurement illuminance that minimizes the error rate) according to the brightness of the substrate 1 (resist). Four images are acquired. And based on the image of the test | inspection block 4 by which the fringe was projected with the optimal measurement illumination intensity, a three-dimensional measurement can be performed. Thereby, even when the board | substrate 1 has a several area | region where brightness (color) differs, the board | substrate 1 (solder 2) can be measured three-dimensionally accurately.

<Various modifications>
The average luminance value of the solder surrounding area 3b, the luminance attribute, and the measured illuminance may be associated with each other and tabulated in advance.

  FIG. 15 is a diagram illustrating a look-up table in which the average luminance value, the luminance attribute, and the measured illuminance of the solder surrounding area 3b are associated with each other.

  In the example shown in FIG. 15, corresponding to the average luminance values 0 to 50, 51 to 101, 102 to 152, 153 to 203, and 204 to 255 of the solder peripheral region 3b (corresponding to the luminance attributes 1 to 5), Measurement illuminances 150, 100, 60, 10, and 5 are associated with each other in order. In other words, this lookup table is tabulated with appropriate measurement illuminance according to the brightness (color) of the substrate 1 (resist).

  A description will be given of how the measurement illuminance is set with respect to the average luminance value of the solder surrounding area 3b (for the luminance attribute).

  In the description here, how the measured illuminance is set for the average luminance values 0 to 50 will be described. In this case, for example, the substrate 1 on which the solder 2 having the average luminance values of the solder surrounding area 3b of 11, 21, 31, 41, 51 is formed is prepared. For each of the five types of solder 2, the error rates of the solder formation region 3a and the solder surrounding region 3b are calculated for each illuminance. The illuminance at which the error rate is minimized is determined for each of the five types of solder 2.

  When the illuminance at which the error rate is minimized with the five types of solder 2 is determined, an average value of illuminance at which the error rate is minimized is calculated. For example, when the illuminance at which the error rate is the minimum is 170, 160, 150, 140, 130 with five types of solder 2, the average value 150 is calculated. In this case, the measurement illuminance 150 is set for the average luminance value of 0-50.

  Similarly, when the average luminance values are 51 to 101, 102 to 152, 153 to 203, and 204 to 255, the measured illuminance is set.

  When allocating the inspection block 4 to the area on the substrate 1, the control unit 16 calculates the average value of the luminance values of the solder surrounding area 3b, and refers to the look-up table shown in FIG. A luminance attribute is set for each of the substrates 1 (see FIG. 3). Then, the control unit 16 assigns the inspection block 4 to the area on the substrate 1 where the solder 2 having the same luminance attribute exists.

  The controller 16 refers to the look-up table shown in FIG. 15 when measuring the substrate 1 three-dimensionally. And the control part 16 is the solder 2 with the brightness | luminance attributes 1-5 (The solder 2 whose average brightness | luminance value of the solder surrounding area | region 3b is 0-50, 51-101, 102-152, 153-203, 204-255) The measurement illuminance at which the fringes are projected is determined for the inspection block 4 including. And the control part 16 projects a stripe with respect to the test | inspection block 4 with the determined measurement illumination intensity. In this case, the stripes are projected at the measurement illuminances 150, 100, 50, 10 and 5 respectively on the inspection block 4 including the solder 2 having the luminance attributes 1, 2, 3, 4 and 5. The control unit 16 images the inspection block 4 on which the stripes are projected, obtains an image of the inspection block 4, and three-dimensionally measures the substrate 1 based on the image of the inspection block 4.

  Even in such processing, the same effects as those of the first embodiment described above can be obtained. That is, the three-dimensional measuring apparatus 100 can accurately three-dimensionally measure the substrate 1 (solder 2) even when the substrate 1 has a plurality of regions with different brightness (colors).

  FIG. 15 shows a case where the average luminance value of the solder peripheral region 3b is classified into five levels. However, the average luminance value of the solder peripheral region 3b is classified into two levels to four levels, or six levels or more. May be. As the number of steps of the average luminance value of the solder surrounding area 3b increases, the number of inspection blocks 4 assigned to one board 1 increases.

  In the above description, the substrate 1 on which the solder 2 for mounting the mounting component is formed as the measurement object 1 has been described as an example. However, the measuring object 1 is not limited to this. Another example of the measurement object 1 is a substrate on which an adhesive for bonding a mounting component is formed. Moreover, the board | substrate with which the land was formed, the board | substrate with which glass was printed, the board | substrate with which the fluorescent substance was printed, etc. are mentioned. In addition, substrates printed with inks such as nano silver ink, polyimide ink, carbon nanotube ink, substrates with silk printing, glass substrates with aluminum electrodes (used as TFT (Thin Film Transistor)), etc. Can be mentioned.

  In the above description, the case where the phase of the fringe phase is shifted four times, four images are acquired, and the phase shift method is applied has been described. However, the present technology can be applied if the number of phase shifts and the number of images are three or more.

The present technology can have the following configurations.
(1) A projection unit that has illumination capable of changing illuminance, and projects a stripe on a measurement object by light from the illumination;
An imaging unit;
The imaging unit captures an image of the measurement object, acquires a luminance value from the captured image of the measurement object, and performs a plurality of inspections on the measurement object based on the acquired luminance value A block is allocated, and for each of the allocated inspection blocks, a measurement illuminance of the illumination is determined, and with the determined measurement illuminance, a stripe is projected onto the inspection block by the projection unit, and the stripe is A three-dimensional measurement apparatus comprising: a control unit that images a projected fringe image of the inspection block by the imaging unit and measures the measurement object three-dimensionally based on the captured stripe image.
(2) The three-dimensional measuring apparatus according to (1) above,
The measurement object has a plurality of inspection objects on the measurement object,
When assigning the plurality of inspection blocks, the control unit acquires a luminance value of an inspection object surrounding area, which is an area around the inspection object, from an image of the measurement object, and acquires the acquired inspection object surrounding area. Based on the luminance value, setting a luminance attribute for each of the plurality of inspection objects, and assigning the inspection block to each area of the measurement object where the inspection object having the same luminance attribute exists, A three-dimensional measurement apparatus that assigns the plurality of inspection blocks to a measurement object.
(3) The three-dimensional measuring apparatus according to (2) above,
When the control unit determines the measurement illuminance for each inspection block, the projection unit projects a stripe on the inspection block, and the imaging unit captures the fringe image of the inspection block on which the stripe is projected. To obtain a luminance value from the fringe image, calculate an error rate in three-dimensional measurement based on the luminance value, change the illuminance of the illumination to calculate the error rate for each illuminance, A three-dimensional measuring apparatus that determines the measured illuminance based on the error rate for each illuminance.
(4) The three-dimensional measuring apparatus according to (3) above,
The control unit, when calculating the error rate, obtains a luminance value of an inspection object formation region that is an area where the inspection object is formed and a luminance value of the surrounding area of the inspection object from the fringe image, A three-dimensional measuring apparatus that calculates the error rate based on a luminance value of the inspection object region and a luminance value of the surrounding region.
(5) The three-dimensional measuring apparatus according to (4) above,
When calculating the error rate, the control unit determines an inspection object having a luminance attribute associated with the inspection block among the plurality of inspection objects included in the inspection block, and relates to the inspection block. A three-dimensional measurement apparatus that calculates the error rate based on a luminance value of the inspection object region and a luminance value of the surrounding region for an inspection object having a luminance attribute having a property.
(6) The three-dimensional measurement apparatus according to any one of (3) to (5) above,
The control unit determines an illuminance that minimizes the error rate as the measured illuminance of the inspection block.
(7) The three-dimensional measuring apparatus according to (2) above,
When the three-dimensional measurement of the measurement object is performed based on the fringe image, the control unit obtains a luminance value of an inspection object formation area, which is an area where the inspection object is formed, and a luminance value of the surrounding area. A three-dimensional measuring apparatus that obtains from the fringe image and measures the measurement object three-dimensionally based on a luminance value of the inspection object region and a luminance value of the surrounding region.
(8) The three-dimensional measuring apparatus according to (7) above,
When the control unit performs three-dimensional measurement of the measurement object based on the fringe image, the inspection object having a luminance attribute having an association with the inspection block among the plurality of inspection objects included in the inspection block And measuring the measurement object three-dimensionally based on the luminance value of the inspection object region and the luminance value of the surrounding region for the inspection object having a luminance attribute related to the inspection block. Dimensional measuring device.
(9) The three-dimensional measuring apparatus according to (1) or (2) above,
A storage unit that stores a table in which the luminance value of the measurement object and the measurement illuminance are associated;
The control unit, when determining the measurement illuminance for each inspection block, refers to the table stored in the storage unit, the measurement corresponding to the luminance value acquired from the image of the measurement object A three-dimensional measuring apparatus that determines the measured illuminance by determining illuminance.
(10) An image of the measurement object is taken,
Obtaining a luminance value from the image of the measured object to be imaged;
Based on the acquired luminance value, assign a plurality of inspection blocks to the measurement object,
For each inspection block assigned, determine the measured illuminance of the illumination,
With the determined measured illuminance, respectively, project a stripe on the inspection block;
Capture a stripe image of the inspection block on which the stripe is projected,
A three-dimensional measurement method that three-dimensionally measures the measurement object based on the captured stripe image.
(11) In the three-dimensional measuring device,
Capturing an image of the measurement object;
Obtaining a luminance value from the imaged image of the measurement object;
Assigning a plurality of inspection blocks to the measurement object based on the acquired luminance value;
Determining a measured illuminance of illumination for each of the assigned inspection blocks;
Projecting stripes on the inspection block, respectively, with the determined measured illuminance;
Capturing a fringe image of the inspection block on which the fringes are projected;
A step of performing a three-dimensional measurement of the measurement object based on the captured stripe image.
(12) First and second color densities corresponding to the first and second areas, respectively, of a substrate having a first area and a second area having a color density different from that of the first area. Get information,
Measuring the first region by irradiating a checkered pattern with illuminance based on the first color density information,
A three-dimensional measurement method in which measurement is performed by irradiating the second region with a lattice pattern with illuminance based on the second color density information.
(13) The three-dimensional measurement method according to (12) above,
The acquisition of the color density is performed by irradiating the first and second regions with lattice stripes having a predetermined illuminance, and is set based on an error rate of the measurement result.
(14) irradiating the first substrate region of the substrate having the first region and the second region having a color density different from the first region with a grid pattern at a first illuminance; Make measurements,
A three-dimensional measurement method in which measurement is performed by irradiating the second substrate region with lattice fringes with a second illuminance different from the first illuminance.

DESCRIPTION OF SYMBOLS 1 ... Board | substrate 2 ... Solder 3a ... Solder formation area 3b ... Solder surrounding area 4 ... Inspection block 10 ... Stage 11 ... Stage moving mechanism 15 ... Imaging part 16 ... Control part 17 ... Memory | storage part 20 ... Projection part 21 ... Light source 100 ... 3 Dimensional measuring device

Claims (10)

A projection unit having illumination capable of changing illuminance, and projecting a stripe on a measurement object by light from the illumination;
An imaging unit;
The imaging unit captures an image of the measurement object, acquires a luminance value from the captured image of the measurement object, and performs a plurality of inspections on the measurement object based on the acquired luminance value A block is allocated, and for each of the allocated inspection blocks, a measurement illuminance of the illumination is determined, and with the determined measurement illuminance, a stripe is projected onto the inspection block by the projection unit, and the stripe is A control unit that captures a projected fringe image of the inspection block by the imaging unit, and three-dimensionally measures the measurement object based on the captured striped image ;
The measurement object has a plurality of inspection objects on the measurement object,
When assigning the plurality of inspection blocks, the control unit acquires a luminance value of an inspection object surrounding area, which is an area around the inspection object, from an image of the measurement object, and acquires the acquired inspection object surrounding area. Based on the luminance value, setting a luminance attribute for each of the plurality of inspection objects, and assigning the inspection block to each area of the measurement object where the inspection object having the same luminance attribute exists, Assigning the plurality of inspection blocks to the measurement object
3D measuring device. The three-dimensional measuring apparatus according to claim 1 ,
When the control unit determines the measurement illuminance for each inspection block, the projection unit projects a stripe on the inspection block, and the imaging unit captures the fringe image of the inspection block on which the stripe is projected. To obtain a luminance value from the fringe image, calculate an error rate in three-dimensional measurement based on the luminance value, change the illuminance of the illumination to calculate the error rate for each illuminance, A three-dimensional measuring apparatus that determines the measured illuminance based on the error rate for each illuminance. The three-dimensional measuring apparatus according to claim 2 ,
The control unit, when calculating the error rate, obtains a luminance value of an inspection object formation region that is an area where the inspection object is formed and a luminance value of the surrounding area of the inspection object from the fringe image, A three-dimensional measuring apparatus that calculates the error rate based on a luminance value of the inspection object region and a luminance value of the surrounding region. The three-dimensional measuring apparatus according to claim 3 ,
When calculating the error rate, the control unit determines an inspection object having a luminance attribute associated with the inspection block among the plurality of inspection objects included in the inspection block, and relates to the inspection block. A three-dimensional measurement apparatus that calculates the error rate based on a luminance value of the inspection object region and a luminance value of the surrounding region for an inspection object having a luminance attribute having a property. The three-dimensional measuring apparatus according to claim 2 ,
The control unit determines an illuminance that minimizes the error rate as the measured illuminance of the inspection block. The three-dimensional measuring apparatus according to claim 1 ,
When the three-dimensional measurement of the measurement object is performed based on the fringe image, the control unit obtains a luminance value of an inspection object formation area that is an area where the inspection object is formed and a luminance value of the surrounding area. A three-dimensional measuring apparatus that obtains from the fringe image and measures the measurement object three-dimensionally based on a luminance value of the inspection object region and a luminance value of the surrounding region. The three-dimensional measuring apparatus according to claim 6 ,
When the control unit performs three-dimensional measurement of the measurement object based on the fringe image, the inspection object having a luminance attribute having an association with the inspection block among the plurality of inspection objects included in the inspection block And measuring the measurement object three-dimensionally based on the luminance value of the inspection object region and the luminance value of the surrounding region for the inspection object having a luminance attribute related to the inspection block. Dimensional measuring device. The three-dimensional measuring apparatus according to claim 1,
A storage unit that stores a table in which the luminance value of the measurement object and the measurement illuminance are associated;
The control unit, when determining the measurement illuminance for each inspection block, refers to the table stored in the storage unit, the measurement corresponding to the luminance value acquired from the image of the measurement object A three-dimensional measuring apparatus that determines the measured illuminance by determining illuminance. Take an image of the measurement object with multiple inspection objects ,
From the captured image of the measurement object, obtain a luminance value of an inspection object surrounding area, which is an area around the inspection object ,
Based on the acquired brightness value of the surrounding area of the inspection object, a brightness attribute is set for each of the plurality of inspection objects,
By assigning an inspection block for each area of the measurement object where the inspection object having the same luminance attribute exists, a plurality of inspection blocks are assigned to the measurement object,
For each inspection block assigned, determine the measured illuminance of the illumination,
With the determined measured illuminance, respectively, project a stripe on the inspection block;
Capture a stripe image of the inspection block on which the stripe is projected,
A three-dimensional measurement method that three-dimensionally measures the measurement object based on the captured stripe image.
In the three-dimensional measuring device,
Capturing an image of a measurement object having a plurality of inspection objects ;
Obtaining a luminance value of an inspection object surrounding area, which is an area around the inspection object, from the imaged image of the measurement object;
Setting a luminance attribute for each of the plurality of inspection objects based on the acquired luminance value of the surrounding area of the inspection object;
Assigning a plurality of inspection blocks to the measurement object by assigning an inspection block to each area of the measurement object where the inspection object having the same luminance attribute exists ;
Determining a measured illuminance of illumination for each of the assigned inspection blocks;
Projecting stripes on the inspection block, respectively, with the determined measured illuminance;
Capturing a fringe image of the inspection block on which the fringes are projected;
A step of performing a three-dimensional measurement of the measurement object based on the captured stripe image.