JP7365477B2 - Three-dimensional measuring device and workpiece work device - Google Patents

Description

The technology disclosed in this specification relates to a three-dimensional measuring device and a workpiece working device.

Conventionally, a phase shift method is known as a method of measuring the height of a measurement target using an imaging unit such as a digital camera (see, for example, Patent Document 1). The phase shift method images the same area of the measurement target multiple times using light that changes black and white using sine waves, shifting the phase by 1/3 or 1/4, and measures the height of the measurement target from the phase difference. It's a method.

Furthermore, a light cutting method is also conventionally known as a method of measuring the height of a measurement target. The light sectioning method projects a spot light or line light onto a measurement target and measures the height based on the principle of triangulation from the position of a light receiving element that receives the light reflected from the measurement target.

Unexamined Japanese Patent Publication No. 2015-1381

However, in the phase shift method, it is necessary to image the same area of the measurement target multiple times while shifting the phase, so it takes time to measure. In addition, since the optical cutting method can only obtain height information only on the line, in order to obtain height information for the entire field of view, it is necessary to move the line by the number of pixels in the direction perpendicular to the line and take images, which requires multiple imaging times. will increase significantly.
This specification discloses a technique that can measure the height of a measurement target in a shorter time than the phase shift method or optical cutting method.

The three-dimensional measuring device disclosed in this specification is a three-dimensional measuring device that measures the height of a measurement target, and has a pattern in which the relative brightness between multiple wavelengths continuously changes in a predetermined direction. A pattern of light in which the calculated values of a predetermined calculation formula in which the brightness of light of each of the wavelengths is a variable does not overlap within one cycle of the change in brightness is used as a reference for the height of the measurement target. a first light source unit that projects diagonally from the predetermined direction toward a reference plane; a first light receiving unit that receives the patterned light reflected by the measurement target for each wavelength; A control unit that determines the height of the measurement target based on the amount of light received by the light receiving unit for each wavelength.

Even when light with multiple wavelengths is reflected from an achromatic surface (black, white, or gray with a brightness in between), the ratio of the brightness of each wavelength (relative brightness between multiple wavelengths) changes. do not. In other words, when multiple wavelengths of light are reflected by an achromatic surface, the ratio of the brightness of each reflected wavelength is the same as the brightness of the achromatic surface (black, white, or gray with intermediate brightness). etc.) and the brightness of the light itself.
Therefore, if the predetermined calculation formula is such that the calculated value will be the same if the ratio of the brightness of light of each wavelength is the same, then the relative brightness between multiple wavelengths will continue in the predetermined direction. Projecting pattern light on an achromatic surface, in which the calculated value of the predetermined calculation formula does not overlap within one cycle of the change in brightness of the light of each wavelength, the pattern light is changing. When calculating the calculated value of the predetermined calculation formula from the received amount of light of each wavelength reflected at each position of the projected area, the calculated value will depend on the brightness of the measurement target and the brightness of the pattern light itself. It becomes a unique value (unique value) for each position.
For this reason, for example, a patterned light is projected onto a reference plane that serves as a height reference in advance, and the amount of received light for each wavelength of the patterned light reflected at each position, or a calculated value calculated from the received light amount using a predetermined calculation formula. By storing , the height of each position can be determined from the amount of light received by the pattern light reflected by the measurement target and the amount of received light or the calculated value stored in advance.
In other words, when the patterned light is used, the calculated value becomes a unique value for each position regardless of the brightness of the measurement target or the brightness of the patterned light itself, so there is no need to image the same area multiple times as in the phase shift method. You can also measure height. Furthermore, the height can be measured without moving and imaging the line by the number of pixels in the direction perpendicular to the line, as in the optical section method.
Therefore, according to the three-dimensional measuring device described above, the height of the measurement target can be measured in a shorter time than with the phase shift method or the optical cutting method.
Note that the surface to be measured is not limited to an achromatic color. If the surface to be measured has a chromatic color, light outside the visible range (in other words, light in the invisible range) may be projected. If light in the invisible region is projected, the same effect can be obtained because the brightness ratio of the light of multiple wavelengths does not change even if it is reflected by a chromatic surface.

The control unit may calculate a calculated value of the predetermined calculation formula from the amount of light received by the first light receiving unit for each wavelength, and calculate the height of the measurement target based on the calculated value. good.

According to the above three-dimensional measuring device, for example, pattern light is projected in advance onto a reference plane that serves as a height reference, and the pattern light reflected at each position is calculated from the amount of light received for each wavelength using a predetermined calculation formula. The calculated value is stored, and the measurement target is calculated based on the calculated value calculated by a predetermined calculation formula from the amount of light received by the first light receiving section for each wavelength and the calculated value stored in advance. The height of can be found.

The pattern light may be projected onto a predetermined range of the reference plane.

According to the three-dimensional measuring device described above, the height of the measurement object can be measured by arranging the measurement object within the above-mentioned predetermined range.

The first light source unit projects the linear pattern light, the first light receiving unit is a plurality of line sensors extending in parallel in the main scanning direction, and the three-dimensional measuring device The measuring device may include a moving unit that moves the one light source unit and the line sensor relative to the measurement target in a sub-scanning direction perpendicular to the main-scanning direction.

According to the three-dimensional measuring device described above, by changing the amount of relative movement, the imaging range can be changed depending on the size of the measurement target.

The first light source section may project the planar pattern light, and the first light receiving section may be an area sensor.

According to the three-dimensional measuring device described above, since the entire measurement target can be imaged at once, the height can be measured in a shorter time than when using a line sensor.

The plurality of wavelengths may be wavelengths outside the visible range.

Wavelengths outside the visible range (hereinafter referred to as wavelengths in the invisible range) are not (or are not) affected by the color of the measurement target, so the height can be measured even if the color of the measurement target is a chromatic color.

In the patterned light, the relative brightness between the plurality of wavelengths may change continuously and periodically, and the fluctuation range of the brightness may vary from cycle to cycle.

If the height of the measurement target exceeds the width of one period of pattern light, if the pattern light is phase-connected and projected for multiple periods, the calculated value will overlap in the period, resulting in incorrect height measurement. there is a possibility.
If the brightness fluctuation range is made different for each period, even if the same calculated value is obtained for each period, it is possible to identify which period the calculated value is for each period based on the difference in the brightness fluctuation width. Therefore, even if the height of the measurement object exceeds the width of one cycle of the pattern light, the height of the measurement object can be measured by one imaging.

The control unit expresses the calculated value obtained from the amount of light received by the first light receiving unit for each wavelength, and the calculated value calculated from the brightness of light of each wavelength of the pattern light. The height of the measurement target may be determined based on a reference plane map.

According to the three-dimensional measuring device described above, the height of the measurement target can be determined by using the reference plane map.

The control unit may create the reference plane map by calculating the calculated value from the theoretical brightness of light of each wavelength of the patterned light using the predetermined calculation formula.

According to the three-dimensional measuring device described above, the reference plane map can be created without using a reference plate, so the reference plane map can be created with a simple configuration.

The control unit includes a reference plate arranged to match the reference plane, and the control unit projects the pattern light onto the reference plate using the first light source unit, and reflects the pattern light on the reference plate to cause the pattern light to be reflected on the reference plate. The reference plane map may be created by calculating the calculated value using the predetermined calculation formula from the amount of light received for each wavelength of the pattern light received by one light receiving section.

According to the above three-dimensional measuring device, since it is equipped with a reference plate, by periodically creating a reference plane map from the reference plate, the brightness of the first light source section, the light receiving sensitivity of the first light receiving section, etc. can be determined. Deterioration in measurement accuracy can be suppressed even if it changes over time.

The control unit includes a reference plate arranged to match the reference plane, and the control unit projects the pattern light onto the reference plate using the first light source unit, and reflects the pattern light on the reference plate to cause the pattern light to be reflected on the reference plate. A partial map is created by calculating the calculated value using the predetermined calculation formula from the amount of light received for each wavelength of the pattern light received by the light receiving section of 1, and the calculated value is calculated from the created partial map. The reference plane map may be created by interpolating other parts of the reference plane map.

According to the three-dimensional measuring device described above, the reference plate can be made smaller than when using a large reference plate that can create the entire reference plane map at once.

The first light source unit projects the pattern light onto a reference plate, which includes a storage unit and is arranged to coincide with the reference plane, and is reflected by the reference plate and received by the first light receiving unit. In the reference plane map representing the calculated value obtained from the received amount of light for each wavelength of the pattern light by the predetermined calculation formula, a plurality of the When the calculated values are defined as rows and the plurality of calculated values arranged in a direction orthogonal to the direction are defined as columns, the storage unit stores an average value of the calculated values for each column, The control unit is configured to control the amount of light received for each wavelength of the pattern light reflected by the measurement target and received by the first light receiving unit, and the average value for each column stored in the storage unit. The height of the measurement target may be determined based on the above.

Since the reference plane map has a large amount of data, storing the entire reference plane map in the storage unit requires a large capacity storage unit, which increases the manufacturing cost of the three-dimensional measuring device.
According to the three-dimensional measuring device described above, since the average value obtained by averaging the calculated values for each column is stored in the storage unit, the amount of data stored in the storage unit is the amount of data for one row of the reference plane map. Therefore, the storage area of the storage unit can be saved compared to the case where the entire reference plane map is stored.

The first light source unit projects the pattern light onto a reference plate, which includes a storage unit and is arranged to coincide with the reference plane, and is reflected by the reference plate and received by the first light receiving unit. In the reference plane map representing the calculated value obtained from the received amount of light for each wavelength of the pattern light by the predetermined calculation formula, a plurality of the When a calculated value is defined as a row, and a plurality of calculated values arranged in a direction orthogonal to the relevant direction are defined as a column, the storage unit stores the above data for each column for a predetermined number of rows at one end in the column direction. An average value obtained by averaging the calculated values is stored, and an average value obtained by averaging the calculated values for each column for a predetermined number of rows at the other end in the column direction is stored, and the control unit Each row of the reference plane map is calculated from the average value for each column of the predetermined number of rows at the one end and the average value for each column of the predetermined number of rows at the other end, which are stored in the storage unit. The reference plane map may be restored by interpolating .

When creating a reference plane map from an image captured by projecting pattern light onto a reference plate, the relative angle between the first light source section and the first light receiving section is tilted, so the reference plane map is created at an angle. may be done. In that case, the measurement target will also be imaged tilted, but since the reference plane map is also tilted, there will be no problem in height measurement.
However, if the average value obtained by averaging the calculated values for each column is stored in the storage section and the stored average value for each column is used as the reference plane map, a non-tilted reference plane map will be used.
According to the above three-dimensional measuring device, the average value for each column of a predetermined number of rows at one end in the column direction and the average value for each column of a predetermined number of rows at the other end are stored in the storage unit. Therefore, the storage area of the storage unit can be saved compared to the case where the entire reference plane map is stored. According to the above-mentioned three-dimensional measuring device, each row of the reference plane map is interpolated from these average values, so that the tilted reference plane map can be restored. Therefore, even if the relative angle between the first light source section and the first light receiving section is tilted, the height can be accurately measured.

The control unit creates a multivalued image representing the brightness of the measurement target from the amount of light received for each wavelength of the pattern light reflected by the measurement target and received by the first light receiving unit. It's okay.

There may be an area in the measurement target that has no level difference, and graphics such as letters or polarity marks are written in that area with a brightness different from the brightness of the area. A three-dimensional measuring device measures the height of a component based on the relative brightness of multiple wavelengths of light, so it is not affected by the brightness of the measurement target. A multivalued image representing the brightness of the measurement target can be created. That is, by capturing an image of the entire part once, it is possible to measure the height of the part and recognize the figure written on the measurement target.

The first light source unit includes a changing unit that relatively changes the direction in which the pattern light is projected onto the measurement target, and the control unit relatively changes the direction in which the first light source unit projects the pattern light onto the measurement target, and the control unit is configured to The pattern light may be sequentially projected onto the first light source section from at least two directions.

If the pattern light is projected onto the measurement target in only one direction, depending on the shape of the measurement target, there may be a shaded area where the pattern light is not projected, making it impossible to measure the entire height of the measurement target.
According to the above-mentioned three-dimensional measuring device, the direction in which the pattern light is projected onto the measurement target is relatively changed and the pattern light is projected sequentially from at least two directions, so when the direction in which the pattern light is projected is only one direction. Compared to this, it is more likely that the height of the object to be measured can be measured over the entire surface.

a second light source unit that projects the pattern light having a different wavelength from the pattern light projected by the first light source unit obliquely toward the reference plane from a direction different from that of the first light source unit; a second light receiving section that receives the pattern light projected by the second light source section and reflected by the measurement target for each of the wavelengths; The pattern light may be simultaneously projected onto the second light source section.

If the pattern light is projected in only one direction, depending on the shape of the object to be measured, there may be a shaded area where the pattern light is not projected, making it impossible to measure the height of the entire surface of the object.
According to the above three-dimensional measuring device, pattern light is projected onto the measurement target from multiple directions, so the height of the measurement target can be measured over the entire surface, compared to when the pattern light is projected in only one direction. It is more likely that you can do it.
Furthermore, according to the three-dimensional measuring device, the wavelength of the pattern light projected by the first light source section and the wavelength of the pattern light projected by the second light source section are different, so they are simultaneously projected onto the measurement target. However, each wavelength of light can be received individually. Therefore, the measurement target can be imaged by simultaneously projecting pattern light from the first light source section and the second light source section. Therefore, the time required for imaging can be shortened, and the height of the measurement target can be measured in a short time.

The workpiece work device disclosed in this specification includes a work unit that performs a predetermined work on the workpiece, and a work unit that measures the height of an object related to the work. A three-dimensional measuring device.

According to the above-mentioned workpiece working device, the height of the object to be measured can be measured in a shorter time than the phase shift method or the optical cutting method.

Schematic diagram of a component mounting line according to Embodiment 1 Schematic diagram of a surface mounter viewed from above Schematic diagram of the head unit viewed from the front Schematic diagram showing a component imaging camera viewed from the X direction Schematic diagram showing a component imaging camera viewed from the Y direction Block diagram showing the electrical configuration of the surface mounter Schematic diagram showing the color wheel (A) is a schematic diagram of a trapezoidal wave, (B) is a schematic diagram of a color image (A) is a schematic diagram of a sine wave, (B) is a schematic diagram of a color image Schematic diagram to explain height measurement of parts Schematic diagram to explain the height measurement procedure Schematic diagram to explain height calculation Schematic diagram showing the bottom side of the part (A) is a schematic diagram for explaining the first method of reducing the amount of data according to the second embodiment, and (B) is a schematic diagram for explaining the second method of reducing the amount of data according to the second embodiment. Schematic diagram for explaining another method 2 of creating a reference plane hue map according to Embodiment 3 (A) is a schematic diagram of a trapezoidal wave according to Embodiment 4, (B) is a schematic diagram of a color image (A) is a schematic diagram of a sine wave, (B) is a schematic diagram of a color image (A) is a schematic diagram of independent waves, (B) is a schematic diagram of a color image Schematic diagram to explain the height measurement procedure (A) is a schematic diagram of a color image according to Embodiment 5, (B) is a schematic diagram of another color image Schematic diagram of a component imaging camera according to Embodiment 6 (A) is a graph of hue values according to another embodiment, and (B) is a graph obtained by correcting the phase of the graph shown in (A).

<Embodiment 1>
Embodiment 1 will be described based on FIGS. 1 to 13. In the following description, reference numerals in the drawings may be omitted for the same structural members except for some.

(1) Component Mounting Line The component mounting line 10 will be explained with reference to FIG. The component mounting line 10 is a line for mounting components E (see FIG. 2, an example of objects to be measured and objects related to work) on a substrate W (see FIG. 2, an example of a workpiece). The component mounting line 10 includes a loader 11, a screen printer 12, a print inspection machine 13, a dispenser 14, a plurality of surface mounting machines 15 (an example of workpiece work equipment), a post-mounting appearance inspection machine 16, a reflow device 17, and an appearance after curing. It includes an inspection device 18 and an unloader 19, which are connected in series via a plurality of conveyors 20.

The loader 11 is a device that supplies substrates W stored in a rack to the screen printing machine 12.
The screen printer 12 is a device that forms a circuit by screen printing solder paste on the surface of the substrate W.
The print inspection machine 13 is a device that inspects the solder screen printed by the screen printing machine 12.

The dispenser 14 is a device that applies adhesive to the substrate W.
The surface mounter 15 is a device that performs a mounting operation (an example of a predetermined operation) of mounting the component E on the substrate W. The configuration of the surface mounter 15 will be described later.
The post-mounting appearance inspection machine 16 is a device that inspects the appearance of the board W after the component E is mounted by the surface mounter 15.

The reflow device 17 is a device that melts solder paste at high temperature and electrically connects the component E and the electrode (so-called land) on the substrate W.
The post-curing appearance inspection device 18 is a device that inspects the appearance of the substrate W after the solder paste melted by the reflow device 17 is cured.
The unloader 19 is a device that stores the substrate W sent out from the post-curing appearance inspection device 18 in a rack.

(1-1) Configuration of surface mounter The configuration of the surface mounter 15 will be described with reference to FIG. 2. In the following description, the X direction shown in FIG. 2 will be referred to as the left-right direction, the Y direction will be referred to as the front-back direction, and the Z direction shown in FIG. 3 will be referred to as the up-down direction. In the following description, the right side shown in FIG. 2 will be referred to as the upstream side, and the left side will be referred to as the downstream side.

The surface mounter 15 is supplied with a base 29, a board transport device 30 that transports the board W, a backup device (not shown), four tape component supply devices 31 that supply components E to be mounted on the board W, and a tape component supply device 31. The device includes a component mounting device 32 for mounting the component E on the board W, a control section 33 (see FIG. 6), and an operation section 34 (see FIG. 6). The board transport device 30, the backup device, the tape component supply device 31, and the component mounting device 32 are examples of the work section.

The board transport device 30 transports the board W from the upstream side in the X direction to the work position A, and transports the board W on which the component E is mounted at the work position A to the downstream side. The substrate transport device 30 includes a pair of conveyor belts 30A and 30B that are driven in circulation in the X direction, a conveyor drive motor 60 (see FIG. 6) that drives the conveyor belts 30A and 30B, and the like. The rear conveyor belt 30A is movable in the front-rear direction, and the interval between the two conveyor belts 30A and 30B can be adjusted according to the width of the substrate W.

A backup device (not shown) is located below the work position A. The backup device includes a plurality of backup pins set at positions depending on the type of substrate W, and when the substrate W is transported to the work position A, the backup pins are raised to support the substrate W from below.

The tape component supply devices 31 are arranged at two locations on each side in the X direction on both sides of the component mounting device 32 in the Y direction, for a total of four locations. A plurality of feeders 35 are attached to these tape component supply devices 31 in a horizontally aligned manner in the X direction. Each feeder 35 is equipped with a reel around which a component tape containing a plurality of components E is wound, an electric tape feeding device for drawing out the component tape from the reel, and the feeder 35 is provided at the end on the working position A side. Components E are supplied one by one from the designated component supplying position.

Note that although the tape component supply device 31 will be described as an example of the component supply device here, the component supply device may be a so-called tray feeder that feeds a tray on which components E are placed, or a tray feeder that feeds a semiconductor wafer. It may be something that does.

The component mounting apparatus 32 includes a head unit 36, a head transport section 37 (an example of a moving section), a board imaging camera 38, and two component imaging cameras 39 (an example of an imaging section). The component imaging camera 39 and the control unit 33 (see FIG. 6) constitute a three-dimensional measuring device according to the first embodiment.

The head unit 36 includes a plurality of (five in this case) mounting heads 40, and these mounting heads 40 attract and release the component E. The head unit 36 according to the present embodiment is of a so-called in-line type, and a plurality of mounting heads 40 are provided side by side in the X-axis direction. The configuration of the head unit 36 will be described later.

The head transport section 37 transports the head unit 36 in the X direction and the Y direction within a predetermined movable range. The head transport section 37 includes a beam 41 that supports the head unit 36 so that it can reciprocate in the X direction, a pair of Y-axis guide rails 42 that supports the beam 41 so that it can reciprocate in the Y direction, and It includes an X-axis servo motor 56 for reciprocating the beam 41 in the Y direction, a Y-axis servo motor 57 for reciprocating the beam 41 in the Y direction, and the like.

A board imaging camera 38 is provided in the head unit 36. The board imaging camera 38 is used to take an image of a fiducial mark (not shown) attached to the board W from above to recognize the position and inclination of the board W, and is arranged with the imaging surface facing down. has been done.

The two component imaging cameras 39 are each provided between the two tape component supply devices 31 arranged in the X-axis direction. The component imaging camera 39 images the component E being attracted to the mounting head 40 from below, and detects the shape of the component E, the position of the component E with respect to the mounting head 40, the rotation angle of the component E around the central axis of the mounting head 40, etc. It is used for recognition purposes, and is placed with the imaging surface facing upward. Further, in this embodiment, the component imaging camera 39 is also used to measure the height of the component E. The configuration of the component imaging camera 39 will be described later.

The configuration of the head unit 36 will be described with reference to FIG. 3. The head unit 36 includes five mounting heads 40, a Z-axis servo motor 58 (see FIG. 6) that raises and lowers each mounting head 40 individually, and an R-axis servo motor 59 (see FIG. 6) that rotates each mounting head 40 around an axis in unison. 6, an example of a change section), etc.

Each mounting head 40 has a nozzle shaft 40A and a suction nozzle 40B detachably attached to the lower end of the nozzle shaft 40A. Negative pressure and positive pressure are supplied to the suction nozzle 40B from an air supply device (not shown) via the nozzle shaft 40A. The suction nozzle 40B suctions the component E when negative pressure is supplied thereto, and releases the component E when positive pressure is supplied thereto.

Although the in-line type head unit 36 has been described here as an example, the head unit 36 may be, for example, a so-called rotary head in which a plurality of mounting heads 40 are arranged on the circumference.

The configuration of the component imaging camera 39 will be described with reference to FIG. 4. The component imaging camera 39 includes a first light source section 39A that projects line-shaped light extending in the Y direction (main scanning direction) onto the lower surface of the component E from diagonally below, and a light receiving section 39B that receives the light reflected by the component E. It is equipped with

As described above, the component imaging camera 39 is also used to measure the height of the component E. Although details will be described later, in this embodiment, a line-shaped pattern light 65 (relative relationship between multiple wavelengths) whose hue, which is one of the three color attributes (hue, saturation, and brightness), continuously changes, is used. An example of patterned light whose brightness is continuously changing) is projected onto the component E and the height is measured. That is, the patterned light 65 can also be said to be patterned light whose hue changes continuously in one direction on a plane having an inclination angle with respect to the optical axis of the patterned light 65.

The first light source section 39A is configured as a color liquid crystal projector to project pattern light 65. Note that the first light source section 39A is not limited to a color liquid crystal projector as long as it can project the patterned light 65. For example, the first light source section 39A may be a projector that projects a pattern image drawn on a transparent sheet.

The light receiving section 39B has three rows of line sensors (not shown) in which a plurality of light receiving elements are arranged in one row in the Y direction (main scanning direction). Each row is arranged in parallel with each other, and each row is provided with a color filter that transmits only light of a different wavelength (color) from among R (red), G (green), and B (blue). There is. The three rows of linear sensors are an example of the first light receiving section.

One pixel from which the density used for calculation is detected is the adjacent light receiving element of the three line sensors mentioned above. As will be described in detail later, the component imaging camera 39 images the component E passing above in time series. At this time, the component imaging camera 39 receives light with the timing at which each line sensor receives the light being slightly shifted so that the light reflected at the same location on the component E is incident on each line sensor. Therefore, the three light receiving elements can be regarded as one pixel. Note that if higher accuracy is required, a configuration may be adopted in which light on one line is simultaneously distributed to each line sensor using a prism or the like.

The pattern light 65 reflected by the component E is received by the line sensor, and an analog voltage corresponding to the amount of light received by each light receiving element is output to the image processing section 53 (see FIG. 6). Note that the component imaging camera 39 may convert the analog voltage into digital data (density) and output it to the image processing section 53.

As shown in FIG. 5, the control unit 33 controls the head conveyance unit 37 so that the component E moves above the component imaging camera 39 from the upstream side to the downstream side (or from the downstream side to the upstream side) in the X direction (sub-scanning direction). The head unit 36 is conveyed so as to pass toward. The component imaging camera 39 images the entire component E by photographing the component E passing above in time series.

(1-2) Electrical configuration of surface mounter The electrical configuration of the surface mounter 15 will be described with reference to FIG. The surface mounter 15 includes a control section 33 and an operation section 34.
The control section 33 includes an arithmetic processing section 50, a motor control section 51, a storage section 52, an image processing section 53, an external input/output section 54, a feeder communication section 55, and the like.

The arithmetic processing unit 50 includes a CPU, ROM, RAM, and the like. The ROM stores control programs and various data. The CPU controls each part of the surface mounter 15 by executing a control program. The RAM is used as a main storage device for the CPU to execute various processes.

The motor control unit 51 rotates each motor such as an X-axis servo motor 56, a Y-axis servo motor 57, a Z-axis servo motor 58, an R-axis servo motor 59, and a conveyor drive motor 60 under the control of the arithmetic processing unit 50.
The storage unit 52 is an external storage device that uses a hard disk, nonvolatile memory, or the like as a storage medium. The storage unit 52 stores various data such as a production program that defines the operation of the surface mounter 15. The production program defines information regarding the number and types of boards W to be produced, information regarding the mounting coordinates and mounting angles of the components E, information regarding the mounting order of the components E, and the like.

The image processing unit 53 creates color image data by converting analog voltages output from the board imaging camera 38 and the component imaging camera 39 into digital data (density) of 256 gradations from 0 to 255 for each RGB. The image processing unit 53 is adjusted so that the maximum gradation is output when the amount of light received at each wavelength is a predetermined value. Furthermore, the first light source section 39A of the component imaging camera 39 is also adjusted so that the maximum amount of light of each wavelength of the pattern light 65 projected becomes the maximum gradation of 256 gradations.
Note that if the board imaging camera 38 or the component imaging camera 39 directly outputs digital data (density), the image processing unit 53 is not necessary.

The external input/output unit 54 is a so-called interface, and is configured to receive detection signals output from various sensors 67 provided in the surface mounter 15. Further, the external input/output unit 54 is configured to control the operation of various actuators 68 based on control signals output from the arithmetic processing unit 50.

The feeder communication unit 55 is an interface for the arithmetic processing unit 50 to communicate with the feeder 35.
The operation unit 34 includes a display device such as a liquid crystal display, and an input device such as a touch panel, a keyboard, and a mouse. The operator can operate the operation unit 34 to make various settings.

(2) Coplanarity FIG. 4 shows an SOP (Small Outline Package) as an example of the component E. The SOP has lead electrodes 61 on two opposing sides of the component body. If there is variation in the height of the bottom surface of each lead electrode 61, when the component E is mounted on the board W, some of the lead electrodes 61 may not come into contact with the board W, which may result in a mounting failure.

Therefore, the control unit 33 measures the height of the lowermost surface of each lead electrode 61 using the component imaging camera 39, and determines the uniformity of the height of the lowermost surface of each lead electrode 61 (so-called coplanarity). When the coplanarity is poor (that is, when the variation in the height of the lowest surface is large), the control unit 33 discards the component E as a defective component in the disposal box.

Here, in FIG. 4, a plane 62 is a plane on which the lower end surface of the suction nozzle 40B is located when measuring the height of the component E. In the following description, the plane 62 will be referred to as a reference plane 62. The reference plane 62 must be perpendicular to the optical axis of the light receiving part 39B, that is, the straight line of the light receiving elements of the three line sensors (or the plane of the light receiving element of the area sensor if the light receiving part 39B has an area sensor). ) is preferably parallel. Note that if there is a tilt with respect to a plane perpendicular to the optical axis of the light receiving section 39B, the tilt may be corrected.

In the following description, the vertical distance between an arbitrary point on the lower surface of the component E and the reference plane 62 will be referred to as the height of that point. In this embodiment, the height can be measured whether the lower surface of the component E is above or below the reference plane 62. If the lower surface of component E is above the reference plane 62, the height will be negative. The height can also be said to be the amount of displacement with respect to the reference plane 62.

Here, the explanation has been given using an SOP as an example of the part E, but the part E is not limited to the SOP. For example, the component E may be a QFP (Quad Flat Package) or a BGA (Ball Grid Array) having a plurality of solder balls on the bottom surface.

(3) Height measurement using a component imaging camera In the following explanation, it is assumed that the color of the lower surface of the component E (the surface onto which the pattern light 65 is projected) is achromatic. Achromatic colors are colors obtained by mixing white and black, and include white, black, and gray. The reason why it is limited to achromatic colors is that when the pattern light 65 consisting of three wavelengths of RGB changes its hue (in other words, the relative brightness of each wavelength of light) when reflected from a chromatic surface, This is because it cannot be measured accurately.

(3-1) Hue First, hue will be explained with reference to FIG. 7. As mentioned above, hue is one of the three attributes of color (hue, saturation, and lightness), and is also called hue or tone. Saturation is the vividness of a color, and value is the brightness (brightness) of a color. Hue can also be said to be the remainder after removing saturation and brightness elements from a color.

・・・ 式１ The hue ring schematically shown in FIG. 7 is a ring-shaped representation of hue. In FIG. 7, R represents red, Y represents yellow, G represents green, C represents cyan, B represents blue, and M represents magenta. In the following explanation, the counterclockwise angle with red as the starting point on the hue wheel will be referred to as the hue value. In the case of the HSV color system, the hue value can be calculated from Equation 1 below. Equation 1 is an example of a predetermined arithmetic expression, and the hue value is an example of a calculated value of the predetermined arithmetic expression.

... Formula 1

The pattern light 65 shown in FIG. 4 is obtained by repeating two cycles of continuously and uniquely changing the hue from 0 degrees to 360 degrees from the front side to the rear side in the Y direction (an example of a predetermined direction). . Since the hue changes continuously and uniquely within the same cycle (in other words, the same hue does not appear twice), if the pattern light for one cycle of hue is received and the hue value is calculated for each pixel, all The hue value of is a unique value.

In addition, since hue is the remainder after removing the saturation element and lightness element from the color, the calculated hue value is the brightness of part E (the brightness of whether the surface color is white, black, or gray). Brightness of the light source (This is the brightness of the light source as a whole, including cases where the brightness differs due to differences in distance from the light source, etc., and even if the height of the imaged object differs partially and the brightness differs. not affected by

For example, when projecting light of a predetermined hue onto component E (light with a predetermined ratio of light intensity of each wavelength of R, G, and B), and calculating the hue value by receiving the light reflected by component E. If the hue of the projected light is the same, the calculated hue value will be the same even if the brightness of the component E or the brightness of the light source is changed.

(3-2) Generation of patterned light A method for generating patterned light 65 will be described with reference to FIGS. 8 and 9. There are various methods for generating the pattern light 65, and here, a method using a trapezoidal wave shown in FIG. 8 and a method using a sine wave shown in FIG. 9 will be explained.

(3-2-1) Method using trapezoidal wave FIG. 8(A) is an example of a trapezoidal wave. FIG. 8(B) shows a color image captured by projecting the patterned light 65 generated using the trapezoidal wave shown in FIG. 8(A) onto the reference plane 62. Here, the brightness of light is expressed in 256 gradations from 0 (black) to 255 (white).

As shown in FIG. 8A, in the method using a trapezoidal wave, the brightness of each color of RGB is changed in a trapezoidal manner, and their phases are shifted by 1/3 (=120 degrees) and overlapped. Specifically, in the example shown in FIG. 8A, one period (360 degrees) of hue is divided into six equal parts. The brightness of the red light changes linearly from 255 to 0 in the range 0 degrees to 60 degrees, 255 to 0 in the range 60 degrees to 120 degrees, 0 in the range 120 degrees to 240 degrees, and 240 degrees to 300 degrees. In the section, it changes linearly from 0 to 255, and in the section from 300 degrees to 360 degrees, it becomes 255.

The brightness of green light changes linearly from 0 to 255 in the range of 0 degrees to 60 degrees, 255 in the range of 60 degrees to 180 degrees, and linearly from 255 to 0 in the range of 180 degrees to 240 degrees. The change is 0 in the range of 240 degrees to 360 degrees.
The brightness of blue light changes linearly from 0 to 255 in the range 0 degrees to 120 degrees, 0 to 255 in the range 120 degrees to 180 degrees, 255 in the range 180 degrees to 300 degrees, and 255 in the range 300 degrees to 360 degrees. In the section, it changes linearly from 255 to 0.

Note that although a trapezoidal wave has been described here as an example, other waveforms may be used as long as either RGB waveform changes continuously. For example, it may be an isosceles triangle (desirably symmetrical). Moreover, it does not have to be symmetrical (in the extreme, it may be a sawtooth wave). Further, like the trapezoidal wave described above, in a section where the brightness of at least one of the RGB lights changes continuously, the brightness of the other colors of light does not need to change.

(3-2-2) Method using sine waves FIG. 9(A) is an example of a sine wave. FIG. 9(B) shows a color image captured by projecting the patterned light 65 generated using the sine wave shown in FIG. 9(A) onto the reference plane 62. As shown in FIG. 9(A), in the method using sine waves, the brightness of each color of RGB light is changed by a sine wave, and the phase is changed by 1/3 so that the sum of the RGB brightnesses is always constant. (=120 degrees) and overlap.

In the example shown in FIG. 9A, the brightness of red light is 255 at 0 degrees and 360 degrees, and 0 at 180 degrees. Green light is 120 degrees out of phase with red light, with a brightness of 255 at 120 degrees and 0 at 300 degrees. Blue light is 240 degrees out of phase with red light, with a brightness of 0 at 60 degrees and a brightness of 255 at 240 degrees.

Note that the light source unit 39A repeats two cycles of projecting one cycle of trapezoidal or sine wave pattern light 65 over a predetermined length onto a reference plane 62 that is a predetermined distance apart, but this predetermined length is determined by design. It is stored in the storage unit 52 as a value. Furthermore, since the light source section 39A is fixed relative to the reference plane 62, pattern light 65 is formed at a predetermined position on the reference plane 62. Therefore, by determining a predetermined origin position in the direction in which the brightness of each wavelength of the pattern light 65 changes continuously, a predetermined phase position of the pattern light 65 is located at a corresponding predetermined distance from the origin. It turns out.

(3-3) Height measurement procedure As shown in FIG. 10, for convenience, here we will explain the case where the parts E1 and E2 are imaged simultaneously and their heights are measured (note that normally, The components E being attracted to the mounting head 40 are imaged one by one). Further, here, an example will be described in which one period of pattern light 65 is phase-connected and two periods of pattern light 65 (trapezoidal wave shown in FIG. 8 or sine wave shown in FIG. 9) is projected.

An image 70 shown in FIG. 11 is a color image (an example of an image) taken by the component imaging camera 39 of the component E1 and the component E2 on which the patterned light 65 shown in FIG. 10 is projected. The density of each RGB of each pixel of the color image 70 is expressed by 256 gradations from 0 to 255, respectively. In the color image 70, a rectangular area 71 indicates the lower surface of the component E1, and a rectangular area 72 indicates the lower surface of the component E2.

Note that since the pattern light 65 is projected obliquely, a portion that becomes a shadow of the component E appears in the color image 70, but the shadow is omitted in the color image 70 for the sake of simplicity. Furthermore, depending on the shape of the component E, a shadow may appear on the rectangular area 71 or the rectangular area 72, but since the lower surface of the component E shown in FIG. .

The image 73 is obtained by arranging an achromatic (for example, white) reference plate (not shown) so as to coincide with the reference plane 62, and in this state, the component imaging camera 39 images the reference plate onto which the patterned light 65 shown in FIG. 10 is projected. This is an image that is displayed by converting the color image into hue values using the above-mentioned equation 1, and then converting the hue values into brightness (density). Hereinafter, a map in which hue values are stored for each position within the reference plane 62 will be referred to as a reference plane hue map. Note that the position within the reference plane 62 is represented by the position of a pixel of the component imaging camera 39.

The density of each pixel of the image 73, which represents the reference plane hue map in lightness, is expressed in 360 gradations from 0 to 359 degrees. In the first embodiment, it is assumed that a reference plane hue map is created and stored in the storage unit 52 in advance, such as when the surface mounter 15 is shipped from the factory.
In creating the reference plane hue map, an elongated achromatic (for example, white) reference plate extending in the Y direction and having a size on which one line of pattern light 65 is projected is arranged so as to overlap with the reference plane 62. Then, one line of pattern light 65 is projected onto the reference plate by the component imaging camera 39, and the reference plane hue for one line is determined from the amount of light received by the line sensor for each wavelength of the pattern light 65 reflected by the reference plate. A map is created. An image 73 shown in FIG. 7 is a plurality of images in which reference plane hue maps for one line extending in the Y direction are arranged in parallel in the X direction, and the reference plane hue map stored in the storage unit 52 is for one line. It's only a minute.

As described above, the image 73 shows an example of the reference plane map as an image. The reference plane hue map is obtained by projecting pattern light 65 having a waveform according to the theoretical value shown in FIG. 8 or 9 onto the reference plane 62 without imaging the pattern light projected onto the reference plate that matches the reference plane 62 The RGB values for each position may be calculated using Equation 1 and stored for each position. Each position may be stored for each assumed pixel of the component imaging camera 39, or may be stored for each different distance interval.
Furthermore, instead of storing the reference plane map in advance, the hue value at each position may be determined by calculation when calculating the height of the object.

A graph 74 is a graph representing the hue values of pixels on the straight line 75 of the image 73 indicating the reference plane hue map. The horizontal axis of the graph 74 is the number of pixels indicating the position on the reference plane (that is, the distance from the reference position on the reference plane 62), and the vertical axis is the hue value from 0 to 359 degrees.
As shown in the graph 74, the hue of the patterned light 65 changes approximately linearly within one period (that is, the hue changes continuously and uniquely within one period). Note that the patterned light 65 only needs to have a hue that changes continuously and uniquely within one period, and is not necessarily limited to one that changes linearly.

The image 76 is an image obtained by converting the density of each RGB of each pixel of the color image 70 into a hue value using Equation 1 described above (more precisely, it is a black and white image in which the hue value is further converted into brightness (density), and hereinafter referred to as hue conversion. (referred to as image 76). The density of each pixel in the hue-converted image 76 is also expressed in 360 gradations.
A graph 77 is a graph representing the hue values of pixels on the straight line 78 of the hue-converted image 76. The horizontal axis of the graph 77 is the number of pixels indicating the position on the reference plane, and the vertical axis is the hue value from 0 to 359 degrees.

The image 79 is an image obtained by subtracting the hue value of the corresponding pixel of the image 73 representing the reference plane hue map from the hue value of each pixel of the hue conversion image 76 (hereinafter referred to as the hue difference image 79).
A graph 80 is a graph representing the hue values of pixels on the straight line 81 of the hue difference image 79. The horizontal axis of the graph 80 is the number of pixels, and the vertical axis is the hue value from 0 to 359 degrees. It is assumed that the straight lines 75, 78, and 81 are the same straight line on the reference plane 62.

For example, consider the position (pixel number) P1 in the X direction (horizontal axis direction) of the graph 77 of the hue conversion image 76. For convenience, it is assumed here that the hue value at position P1 is 200 degrees. In the graph 74 of the image 73 showing the reference plane hue map, the position where the hue value is 200 degrees is position P2. That is, the light that would have been received at position P2 if component E1 was not present is now received at position P1 due to the presence of component E1.

In this case, as shown in FIG. 12, if the inclination of the patterned light 65 projected from the first light source section 39A is θ, then the distance (number of pixels) between the positions P1 and P2 and the inclination θ of the patterned light 65 are The height of component E1 at position P1 can be calculated from . Specifically, the height can be calculated using Equation 2 shown below.
Height = distance between position P1 and position P2 x tanθ... Formula 2

The unit of the height calculated by the above equation 2 is the number of pixels. Note that the unit can also be converted from the number of pixels to the distance [m] on the reference plane 62 by multiplying by a predetermined proportionality coefficient.

Note that when the pattern light 65 is not parallel light, the inclination θ of the pattern light 65 differs depending on the position within the region onto which the pattern light 65 is projected. Therefore, if the pattern light 65 is not parallel light, the inclination θ may be corrected depending on the position.

By the way, as shown in the graph 74 of the reference plane hue map of the image 73, in this embodiment, the position (pixel number) and the hue value correspond approximately linearly. The difference (hue difference) between the hue value of P1 and the hue value of position P1 in the hue conversion image 76 is approximately directly proportional to the distance between position P1 and position P2. Therefore, in the present embodiment, the control unit 33 calculates the height of the position P1 from the hue difference rather than from the distance between the positions P1 and P2.

Specifically, when the control unit 33 considers that the difference (hue difference) between the hue value at the position P1 and the hue value at the position P1 in the hue conversion image 76 is directly proportional to the distance between the positions P1 and P2, acquires the hue difference at position P1 from the hue difference image 79, and calculates the height using Equation 3 below.
Height = Hue difference x tanθ... Formula 3

Since there is a proportional relationship between the hue difference and the distance, the unit of height calculated by Equation 3 above is equivalent to the number of pixels. Therefore, the unit can also be converted into the number of pixels by multiplying by a predetermined proportionality coefficient. Furthermore, it can also be converted to a distance [m] on the reference plane 62 by multiplying by another proportionality coefficient.

Note that the position (pixel number) and the hue value only need to correspond one-to-one, and do not necessarily have to correspond linearly. If the position and hue value do not correspond linearly, the height may be calculated using Equation 2 described above. That is, the hue value at position P1 may be obtained, and the position P2 having the same hue value as this hue value may be searched from the hue values stored in the reference plane hue map, and the calculation may be performed using Equation 2.

(4) Creation of a multivalued image representing the brightness of the component As shown in FIG. It may be written as . The control unit 33 creates a multivalued image representing the brightness of the lower surface of the component E from the color image 70 created in the process of measuring the height of the component E, analyzes the created multivalued image, and generates the figure 85. recognize.

A method for creating a multivalued image representing the brightness of the lower surface of the component E from the color image 70 will be described below. The method for creating a multivalued image differs depending on the method for creating the patterned light 65. Here, the method of creating a multivalued image will be explained for each method of creating the patterned light 65.

(4-1) When creating a patterned light using a trapezoidal wave As shown in FIG. 8(A) described above, the trapezoidal wave always has a maximum value of one of RGB. Therefore, the control unit 33 creates a multivalued image by obtaining the maximum value of RGB brightness (density) for each pixel from the color image 70, as shown in Equation 4 below. In the case of the trapezoidal wave in FIG. 8A, the maximum value for each position (pixel) is always the maximum density, so a constant brightness can be obtained.
Brightness = Max (R, G, B) ... Formula 4

(4-2) When creating pattern light using a sine wave As shown in FIG. 9(A) described above, the sum of RGB brightness of a sine wave is always constant. Therefore, the control unit 33 creates a multivalued image by obtaining the sum of RGB brightness (density) for each pixel from the color image 70, as shown in Equation 5 below.
Brightness=R+G+B... Formula 5

(5) Effects of Embodiment According to the three-dimensional measuring device (component imaging camera 39 and control unit 33) according to the first embodiment, patterned light 65 whose hue is continuously changing is projected onto the component E. When the patterned light 65 is used, the hue value becomes a unique value for each position regardless of the brightness of the component E or the brightness of the patterned light 65 itself, so there is no need to image the same area multiple times as in the phase shift method. Can measure height. Furthermore, the height can be measured without moving and imaging the line by the number of pixels in the direction perpendicular to the line, as in the optical section method. Therefore, the height of the component E can be measured in a shorter time than with the phase shift method or the optical cutting method.

According to the three-dimensional measuring device, since a line sensor is used as the light receiving section 39B, the imaging range can be changed according to the size of the component E by changing the amount of relative movement between the component imaging camera 39 and the component E. can. Furthermore, since the irradiation range of the patterned light 65 can be narrowed, the size of the three-dimensional measuring device can be reduced.

According to the three-dimensional measuring device, a multivalued image representing the brightness of the lower surface of the component E is created from the color image 70 created in the process of measuring the height of the component E, so by imaging the entire component E at once, , the height of the component E can be measured and the figure 85 written on the bottom surface of the component E can be recognized.

<Embodiment 2>
In the first embodiment described above, the first light source section 39A projects a line-shaped pattern of light, and a line sensor is used as the light receiving section 39B. In the first embodiment, the reference plane hue map for one line is stored in the storage unit 52.

On the other hand, the first light source section 39A according to the second embodiment projects planar pattern light, and the light receiving section 39B is a color light receiving section in which light receiving elements of each color of RGB are two-dimensionally arranged in a predetermined arrangement pattern. This is an area sensor (hereinafter simply referred to as an area sensor). In the second embodiment, a reference plane hue map is created using a planar reference plate. Specifically, planar pattern light is projected onto a planar reference plate by the first light source unit 39A, and the area sensor receives the pattern light reflected by the reference plate based on the amount of light received for each wavelength. A reference plane hue map is created.

Since the reference plane hue map according to the second embodiment is two-dimensional data, the amount of data is larger than that of the reference plane hue map according to the first embodiment. Therefore, in the second embodiment, the amount of data of the reference plane hue map is reduced and stored. Here, two methods will be described as methods for reducing the amount of data of the reference plane hue map.

(1) Method 1
Method 1 will be explained with reference to FIG. 14(A). In method 1, in the reference plane hue map created by imaging the reference plate, the direction in which the brightness of each wavelength of pattern light changes (the left-right direction in FIG. 14) is defined as the row direction, and the direction in which the brightness of each wavelength of pattern light changes is defined as the row direction. When the orthogonal direction (vertical direction in FIG. 14) is defined as the column direction, the average value (hereinafter referred to as representative hue value) obtained by averaging the hue values for each column is stored in the storage unit 52.

The control unit 33 uses the representative hue value for each column stored in the storage unit 52 as a reference plane hue map. Specifically, the control unit 33 creates the hue difference image 79 by subtracting from each pixel of the hue conversion image 76 the representative hue value of the column in which the pixel is located.

(2) Method 2
Method 2 will be explained with reference to FIG. 14(B). When capturing an image of the reference plane 62, the relative angle between the first light source section 39A and the light receiving section 39B is shifted, so that the reference plane hue is different from the oblique plane part as shown in FIG. 14(B). A map may be created. In this case, if only the representative hue values of each column are stored in the storage unit 52 as in Method 1, the hue values at the top of the reference plane hue map (an example of one end in the column direction) and the bottom part of the reference plane hue map (an example of the other end in the column direction) is significantly different from the representative hue value.

Therefore, in method 2, in the reference plane hue map created by imaging the reference plate, the average value of hue values is stored for each column for a predetermined number of rows (for example, 2 to 3 rows) at the top of the reference plane hue map. In addition, the average value of hue values for each column of a predetermined number of rows at the bottom of the reference plane hue map is stored in the storage unit 52.
The control unit 33 determines the reference plane from the average value for each column of a predetermined number of rows at the upper part of the reference plane hue map and the average value for each column of a predetermined number of rows at the lower part of the reference plane hue map, which are stored in the storage unit 52. By linearly interpolating each row of the hue map, the oblique reference plane hue map is restored.

(3) Effects of Embodiment According to method 1, the average value (representative hue value) obtained by averaging the hue values for each column is stored in the storage unit 52, so the amount of data stored in the storage unit 52 is equal to that of the reference plane hue map. This is the amount of data for one line. Therefore, the storage area of the storage unit 52 can be saved compared to the case where the entire reference plane hue map is stored.

According to method 2, the average value for each column of a predetermined number of rows at one end in the column direction and the average value for each column of a predetermined number of rows at the other end are stored in the storage unit 52. , the storage area of the storage unit 52 can be saved compared to the case where the entire reference plane hue map is stored. According to method 2, the reference plane hue map is restored from those average values, so that the reference plane hue map in a tilted state can be restored. Therefore, even if the relative angle between the first light source section 39A and the light receiving section 39B is tilted, the height can be accurately measured.

<Embodiment 3>
In the first embodiment described above, the case where the reference plane hue map is created by capturing an image of the reference plate has been described as an example. In the third embodiment, another method for creating a reference plane hue map will be described.

(1) Other method 1
Another method 1 is to create a reference plane hue map by calculation. Specifically, for example, the control unit 33 converts the brightness (0 to 255) of the light of each RGB color shown in FIG. Create hue maps logically. For example, in the case of 120 degrees as shown in FIG. 8A, the control unit 33 converts the brightness of each RGB color light (0, 255, 0) at 120 degrees into the above-mentioned equation 1 to convert it into a hue value.

The above-mentioned 120 degrees is a phase value. The phase value is the position on the reference plane 62, that is, the distance (for example, X) from the phase origin. The brightness of each RGB color light at distance X is a function of a trapezoidal wave or a sine wave. Therefore, the hue value is expressed as a function of distance X. Since the hue value is a function of the distance X, the position where the hue value should be can be calculated from the hue value. As described above, it may be stored in the reference plane hue map, or only the calculation formula may be stored without being stored in the reference plane hue map.

Another method 1 is that the first light source section 39A can faithfully reproduce the pattern light 65 of the calculated hue value (design value), and the light receiving section 39B can also receive the pattern light 65 and reproduce the above-mentioned design value. It can be applied when it can be faithfully reproduced (or when it can be considered that it can be faithfully reproduced).

(2) Other method 2
Other method 2 will be described with reference to FIG. 15. In another method 2, an elongated achromatic (for example, white) reference plate 87 extending in the Y direction is arranged on the left side of the imaging range 86 of the component imaging camera 39, on the right side of the imaging range 86, or both. The control unit 33 creates a partial map by calculating a hue value from the density of each pixel converted from the amount of light received for each wavelength of the pattern light 65 reflected by the reference plate 87. Then, the control unit 33 creates a reference plane hue map by interpolating other parts of the reference plane hue map from the created partial map in the same manner as method 1 and method 2 of the second embodiment described above.

(3) Effects of the Embodiment In other method 1, it is not necessary to store the reference plane hue map in the storage unit 52, so the storage area of the storage unit 52 can be saved. In addition, in the other method 1, the reference plane hue map is created without using a reference plate, so the reference plane hue map can be created with a simpler configuration than when using a reference plate.

In the other method 2, it is not necessary to store the reference plane hue map in the storage unit 52, so the storage area of the storage unit 52 can be saved. Further, in the other method 2, the reference plate 87 can be made smaller than when using a large reference plate that can create the entire reference plane hue map at once. In another method 2, the reference plate 87 is imaged periodically to create a reference plane hue map (or the reference plate 87 is imaged each time the height of the component E is measured and the reference plane hue map is created). By creating a map), even if the brightness of the first light source section 39A or the light receiving sensitivity of the light receiving section 39B changes over time, a decrease in measurement accuracy can be suppressed.

<Embodiment 4>
In the first embodiment described above, one period of hue is phase-connected to project a plurality of periods of pattern light 65. On the other hand, in the fourth embodiment, a pattern of light whose hue changes continuously and periodically and whose saturation value (width of variation in brightness) differs for each cycle is projected.

(1) Generation of patterned light Methods for generating the patterned light described above include a method using a trapezoidal wave, a method using a sine wave, a method using an independent wave, and the like. Each method will be explained below. Note that in the following description, RGB will be used as an example of the wavelength of the pattern light, but the wavelength is not limited to RGB.

(1-1) Method using trapezoidal wave FIG. 16(A) is an example of a trapezoidal wave. FIG. 16(B) shows a color image captured by projecting pattern light generated using the trapezoidal wave shown in FIG. 16(A) onto the reference plane 62.
As shown in FIG. 16(A), in the method using a trapezoidal wave, the brightness of the upper side of the trapezoid is set to 255 in every cycle, and the brightness of the lower side of the trapezoid is gradually lowered as each cycle passes. do. Specifically, in the example shown in FIG. 16A, the brightness of the lower side of the trapezoid is 150 in the first cycle, 100 in the second cycle, 50 in the third cycle, and 0 in the fourth cycle. The brightness at the bottom of the image gradually decreases.

・・・ 式６ When using a trapezoidal wave, the hue value, brightness value, and saturation value can be calculated from the following formula. Equation 6 is an example of a predetermined arithmetic expression.

... Formula 6

・・・ 式８ Brightness value = MAX (R, G, B) ... Formula 7

... Formula 8

(1-2) Method using sine waves FIG. 17(A) is an example of a sine wave. FIG. 17(B) shows a color image captured by projecting the pattern light generated using the sine wave shown in FIG. 17(A) onto the reference plane 62. As shown in FIG. 17A, in the method using a sine wave, the amplitude of the sine wave (width of variation in brightness) is increased stepwise every time one cycle passes.

・・・ 式９ When using a sine wave, the hue value, brightness value, and saturation value can be calculated from the following equations. Equation 9 is an example of a predetermined arithmetic expression.

... Formula 9

・・・ 式１１ Brightness value = R + G + B ... Formula 10

... Formula 11

(1-3) Method using independent waves FIG. 18(A) is an example of independent waves. FIG. 18(B) shows a color image captured by projecting the patterned light generated using the independent waves shown in FIG. 18(A) onto the reference plane 62. As shown in FIG. 18A, in the method using independent waves, the brightness is changed in different change patterns for each RGB. Specifically, in the example shown in FIG. 18(A), the brightness of red is constant at 255. The brightness of green is 0 at the beginning of the cycle and changes linearly to 255 at the end of the cycle. The brightness of blue increases step by step as each cycle passes.

When using independent waves, the hue value, brightness value, and saturation value can be calculated from the following formulas. Equation 12 is an example of a predetermined arithmetic expression.
Hue value=G/R... Formula 12
Brightness value = R... Formula 13
Saturation value = B/R... Formula 14

Note that in the above example, R (red) is set to a constant value (reference) as brightness, G (green) is changed continuously as hue, and B (blue) is changed as saturation in stages. , which color (wavelength) is to be used as the hue, brightness, and saturation can be determined as appropriate.

(2) Height measurement procedure An image 90 shown in FIG. 19 is a color image taken of the reference plane 62 onto which the patterned light described above is projected. Note that for convenience, part E is omitted in FIG. 19.
The image 91 is an image converted from the color image 90 (hereinafter referred to as a hue-converted image 91). A graph 92 is a graph representing the hue values of pixels on the straight line 93 of the hue-converted image 91. As shown in the graph 92, the hue value of the pixel of the hue conversion image 91 changes linearly from 0 degrees to 360 degrees every cycle.

The image 94 is an image representing the saturation value converted from the color image 90 (hereinafter referred to as the saturation converted image 94). In the case of the HSV color system, the saturation value can be calculated from Equation 8 described above. A graph 95 is a graph representing the saturation values of pixels on the straight line 96 of the saturation-converted image 94. As shown in the graph 95, the saturation value of the pixel of the saturation-converted image 94 is constant within one cycle, and increases stepwise as each cycle passes.

The image 97 is an image obtained by correcting the hue-converted image 76 based on the saturation-converted image 94 (hereinafter referred to as the corrected hue image 97). Specifically, as shown in Equations 15 to 17 below, the corrected hue image 97 changes the hue value of each pixel of the hue conversion image 91 by 360 every time the saturation value of the saturation conversion image 94 changes. This is an image corrected by adding .
S0: Corrected hue value = hue value + 0... Equation 15
S1: Corrected hue value = hue value + 360... Equation 16
S2: Corrected hue value = hue value + 720... Equation 17

A graph 98 is a graph representing the hue values of pixels on the straight line 99 of the corrected hue image 97. As shown in the graph 98, the hue value of each pixel of the corrected hue image 97 becomes a unique value over all cycles. The graph 98 becomes a perfectly linear linear function if the pattern light 65 is as theoretical and the light receiving section 39B is as theoretical.

(2) Effects of Embodiment According to the three-dimensional measuring device according to Embodiment 4, the hue of the pattern light changes continuously and periodically, and the saturation value (brightness fluctuation range) changes periodically. ) are different, so even if the same calculated value is calculated in each cycle, it is possible to identify which cycle the calculated value is from based on the difference in the saturation value. Therefore, even if the height of the component E exceeds the width of one cycle of the pattern light, the height of the object to be measured can be measured with one imaging.

<Embodiment 5>
In the fifth embodiment, the component imaging camera 39 relatively changes the direction in which the pattern light 65 is projected onto the component E, and the component E is imaged by the component imaging camera 39 in each direction. Specifically, as described above, the head unit 36 includes the R-axis servo motor 59 that rotates the mounting head 40 that picks up the component E around the axis. The control unit 33 rotates the component E by rotating the mounting head 40 around the axis. As a result, the direction in which the component imaging camera 39 projects the pattern light 65 onto the component E is changed. The control unit 33 images the component E using the component imaging camera 39 in a plurality of directions (for example, 0 degrees and 180 degrees).

Note that the direction in which the pattern light 65 is projected is not limited to two directions, and may be projected from three or more directions. However, in order to accurately measure the height, it is desirable to include at least two opposing directions (for example, 0 degrees and 180 degrees).

FIG. 20(A) shows a color image taken at 0 degrees, and FIG. 20(B) shows a color image taken at 180 degrees. In FIG. 20(A), there is a shaded area on the right side of the component E where the pattern light 65 is not projected, but in FIG. 20(B), the pattern light 65 is projected from the opposite side, so there is a shadow on the right side of the component E. has disappeared. The control unit 33 measures the height of the component E by using these two color images.

According to the three-dimensional measuring device according to the fifth embodiment, the direction in which the pattern light 65 is projected onto the component E is relatively changed and the pattern light 65 is sequentially projected from at least two directions. It is more likely that the height of the component E can be measured over the entire surface than when measuring only in one direction.

Furthermore, according to the three-dimensional measuring device, the direction in which the component imaging camera 39 projects the pattern light 65 onto the component E is relatively changed by using the R-axis servo motor 59. There is no need to provide a separate configuration. Therefore, the cost for relatively changing the direction can be suppressed.

<Embodiment 6>
As shown in FIG. 21, the component imaging camera 39 according to the sixth embodiment includes a second light source section 101. The second light source section 101 is also configured as a projector. The second light source section 101 generates a pattern of light 102 in which the relative brightness between a plurality of wavelengths is continuously changing, and which has a different wavelength from the pattern light 65 projected by the first light source section 39A. Light 102 is projected onto component E from a direction different from that of first light source section 39A (for example, a direction rotated by 180 degrees around the axis of mounting head 40 from first light source section 39A).

Here, the different wavelengths refer to wavelengths in a range that does not overlap with the RGB range, such as wavelengths in the ultraviolet region and wavelengths in the infrared region.
Note that the pattern light 102 may have a wavelength within the RGB range as long as it does not overlap with the pattern light 65 projected by the first light source section 39A. Here, "not overlapping" means that none of the plurality of wavelengths of the patterned light 102 overlaps between the minimum value and the maximum value of the plurality of wavelengths of the patterned light 65. Furthermore, the pattern light 102 may be visible light (wavelength in the visible range) or invisible light (wavelength in the invisible range).

Further, both the first light source section 39A and the second light source section 101 may project invisible light. For example, even if the first light source section 39A projects a pattern light consisting of light of two or more wavelengths in the ultraviolet region, and the second light source section 101 projects a pattern light consisting of light of two or more wavelengths in the infrared region. good.

In addition to the three rows of RGB line sensors (an example of the first light receiving section) described above, the light receiving section 39B includes a plurality of line sensors that receive pattern light 102 projected by the second light source section 101 and reflected by the component E. line sensor (an example of the second light receiving section). These line sensors are provided with filters that transmit only light of wavelengths different from those of other line sensors among the wavelengths of light constituting the pattern light 102.

Since the pattern light 65 projected by the first light source section 39A and the pattern light 102 projected by the second light source section 101 have different wavelengths, even if they are projected simultaneously, each line sensor It can only receive light with wavelengths corresponding to . Therefore, the control unit 33 projects the pattern lights 65 and 102 onto the component E simultaneously from the first light source section 39A and the second light source section 101 to image the component E in order to shorten the time required for imaging.
The control unit 33 then generates a color image created by receiving the pattern light 65 projected by the first light source unit 39A and an image created by receiving the pattern light 102 projected by the second light source unit 101. The height of part E is determined using

According to the three-dimensional measuring device according to the sixth embodiment, the pattern lights 65 and 102 are projected onto the component E from two directions, so that the height of the component E can be more likely to be measured over the entire surface. Furthermore, according to the three-dimensional measuring device, the pattern lights 65 and 102 are simultaneously projected onto the component E from the first light source section 39A and the second light source section 101 to image the component E, thereby reducing the time required for imaging. can. Therefore, the height of the component E can be measured in a short time.

<Other embodiments>
The technology disclosed by this specification is not limited to the embodiments described above and illustrated in the drawings; for example, the following embodiments are also included within the technical scope disclosed by this specification.

(1) In the first embodiment, three visible lights of RGB are used as an example of the plurality of wavelengths, but the plurality of wavelengths may be wavelengths in an invisible region (for example, near-infrared light). Since the wavelength in the invisible region is not affected (or hardly affected) by the color of the component E, the height can be measured even if the color of the bottom surface of the component E is a chromatic color. Note that when using a wavelength in an invisible region, the light receiving wavelength of the light receiving section 39B must also be matched to that wavelength.

(2) In the above embodiment, a projector is used as an example of the first light source section 39A and the second light source section 101, but these light source sections are not limited to a projector. For example, the light source section may be a diffraction grating, a prism, an optical filter, a sequential array of multi-color LEDs, or the like.

(3) In the above embodiment, three wavelengths have been described as an example of a plurality of wavelengths, but the plurality of wavelengths is not limited to three wavelengths, and may be two or more wavelengths.

(4) In the above embodiment, the HSV color system is used as an example of the color system for color images, but the color system is not limited to the HSV color system. For example, the color system may be YIQ color system, Lab color system, or the like.

・・・ 式１８ In the case of the YIQ color system, the hue value can be calculated using Equation 18 below. Equation 18 is an example of a predetermined arithmetic expression.

... Formula 18

・・・ 式２２ In the case of the Lab color system, the hue value can be calculated using Equations 19 to 22 below. In Equation 22, Xn, Yn, and Zn are the values of XYZ in the reference white color. Equations 19 to 22 are examples of predetermined arithmetic expressions.
X=0.412R+0.358G+0.181B... Formula 19
Y=0.213R+0.715G+0.072B... Formula 20
Z=0.019R+0.119G+0.951B... Formula 21

... Formula 22

FIG. 22(A) is a graph showing hue values calculated using the HSV color system, the YIQ color system, and the Lab color system. As shown in the figure, each color system is out of phase. FIG. 22(B) is a graph corrected so that the phases of each color system match.

(5) In the first embodiment, the case where a reference plane hue map created in advance is stored in the storage unit 52 has been described as an example. On the other hand, a large reference plate that can create the entire reference plane hue map at once may be provided, and the reference plane hue map may be created from the reference plate. In this way, the height can be accurately measured even if the accuracy with which the first light source section 39A faithfully reproduces the patterned light and the accuracy with which the light receiving section 39B faithfully reproduces the patterned light are low.

(6) In the above embodiment, the component imaging camera 39 has been described as an example of the imaging section, but the imaging section may also be the board imaging camera 38.

(7) In the above embodiment, the surface mounter 15 has been described as an example of the workpiece working device, but the workpiece working device is not limited to the surface mounter 15. For example, the workpiece processing device may be a screen printer 12, a print inspection device 13, a dispenser 14, a post-mounting visual inspection device 16, or a post-curing visual inspection device 18.
For example, in the case of the screen printing machine 12, it is equipped with an imaging section with the imaging surface facing downward, and a transport section that transports the imaging section in a horizontal direction above the substrate W, and transports the imaging section and transfers the imaging section to the substrate W. The height of the solder paste printed on the substrate W may be measured by capturing images of each part from above.
Further, in the case of the dispenser 14, since it is equipped with a head unit 36 that holds a dispenser head for applying adhesive so as to be movable in the vertical direction, and a conveying section that conveys the head unit 36 in the horizontal direction, it is possible to take an image. The height of the adhesive applied to the substrate W is measured by disposing the imaging section with its surface facing down in the head unit 36 and transporting the imaging section to image each part of the substrate W from above. It's okay.
The same applies to the printing inspection machine 13, the post-mounting visual inspection machine 16, the post-curing visual inspection machine 18, and the like.

15... Surface mounting machine (an example of a workpiece working device), 30... Board transport device (an example of a working part), 31... Tape component supply device (an example of a working part), 32... Component mounting device (an example of a working part), 33... Control section (an example of a three-dimensional measuring device), 37... Head transport section (an example of a moving section), 39... Component imaging camera (an example of an imaging section, three-dimensional measuring device), 39A... First light source section, 39B...First light receiving section, 52...Storage section, 59...R-axis servo motor (an example of a changing section), 62...Reference plane, 65...Pattern light, 70...Color image (an example of an image), 73...Reference plane Hue map (an example of a reference plane map), 87... Reference plate, 90... Color image (an example of an image), 100... Pattern light, 101... Second light source section, 102... Pattern light, E (E1, E2)... Parts (an example of measurement target)

Claims (15)

A three-dimensional measuring device that measures the height of a measurement target,
Pattern light in which the relative brightness between multiple wavelengths continuously changes in a predetermined direction, and the calculated value of a predetermined calculation formula using the brightness of the light of each wavelength as a variable is the brightness. a first light source unit that projects pattern light that does not overlap within one period of change obliquely from the predetermined direction toward a reference plane that serves as a reference for the height of the measurement target;
a first light receiving unit that receives the pattern light reflected by the measurement target for each wavelength;
a control unit that determines the height of the measurement target based on the amount of light received by the first light receiving unit for each wavelength;
Equipped with
The predetermined calculation formula is such that the calculated value will be the same if the ratio of the brightness of the light of each wavelength is the same,
The control unit calculates a calculated value of the predetermined calculation formula from the amount of light received by the first light receiving unit for each wavelength, and calculates the height of the measurement target based on the calculated value,
In the three-dimensional measurement device, the pattern light has a relative brightness between the plurality of wavelengths that continuously and periodically changes, and a range of variation in the brightness differs for each period. The three-dimensional measuring device according to claim 1,
A three-dimensional measurement device in which the pattern light is projected onto a predetermined range of the reference plane. The three-dimensional measuring device according to claim 1 or claim 2,
The first light source unit projects the linear pattern light,
The first light receiving section is a plurality of line sensors extending in parallel in the main scanning direction,
The three-dimensional measuring device includes a moving unit that moves the first light source unit and the line sensor relative to the measurement target in a sub-scanning direction perpendicular to the main-scanning direction. The three-dimensional measuring device according to claim 1 or claim 2,
The first light source unit projects the planar pattern light,
A three-dimensional measuring device, wherein the first light receiving section is an area sensor. The three-dimensional measuring device according to any one of claims 1 to 4,
A three-dimensional measuring device, wherein the plurality of wavelengths are wavelengths outside the visible range. The three-dimensional measuring device according to claim 1,
The control unit expresses the calculated value obtained from the amount of light received by the first light receiving unit for each wavelength, and the calculated value calculated from the brightness of light of each wavelength of the pattern light. A three-dimensional measurement device that calculates the height of the measurement target based on a reference plane map. The three-dimensional measuring device according to claim 6 ,
The control unit is a three-dimensional measuring device that creates the reference plane map by determining the calculated value using the predetermined calculation formula from the theoretical brightness of light of each wavelength of the pattern light. The three-dimensional measuring device according to claim 6 ,
a reference plate arranged to match the reference plane;
The control unit projects the pattern light onto the reference plate using the first light source unit, and controls the wavelength of the pattern light reflected by the reference plate and received by the first light receiving unit. A three-dimensional measurement device that creates the reference plane map by calculating the calculated value from the amount of received light using the predetermined calculation formula. The three-dimensional measuring device according to any one of claims 1 to 8 ,
The control unit creates a multivalued image representing the brightness of the measurement target from the amount of light received for each wavelength of the pattern light reflected by the measurement target and received by the first light receiving unit. , three-dimensional measuring device. A three-dimensional measuring device according to any one of claims 1 to 9 ,
The first light source unit includes a changing unit that relatively changes the direction in which the pattern light is projected onto the measurement target,
The control section is a three-dimensional measurement device, wherein the control section causes the first light source section to project the pattern light sequentially from at least two directions by relatively changing the direction using the changing section. a working part that performs a predetermined work on the work;
The three-dimensional measuring device according to any one of claims 1 to 10, which measures the height of an object related to the work;
A workpiece handling device comprising: A three-dimensional measuring device that measures the height of a measurement target,
Pattern light in which the relative brightness between multiple wavelengths continuously changes in a predetermined direction, and the calculated value of a predetermined calculation formula using the brightness of the light of each wavelength as a variable is the brightness. a first light source unit that projects pattern light that does not overlap within one period of change obliquely from the predetermined direction toward a reference plane that serves as a reference for the height of the measurement target;
a first light receiving unit that receives the pattern light reflected by the measurement target for each wavelength;
a control unit that determines the height of the measurement target based on the amount of light received by the first light receiving unit for each wavelength;
Equipped with
The predetermined calculation formula is such that the calculated value will be the same if the ratio of the brightness of the light of each wavelength is the same,
The control unit calculates a calculated value of the predetermined calculation formula from the amount of light received by the first light receiving unit for each wavelength, and calculates the height of the measurement target based on the calculated value,
In the three-dimensional measurement device, the pattern light has a relative brightness between the plurality of wavelengths that continuously and periodically changes, and a chroma value that differs for each period. A three-dimensional measuring device according to any one of claims 1 to 10 ,
The three-dimensional measuring device, wherein the calculated value is a hue value. The three-dimensional measuring device according to claim 9 ,
The pattern light is light in which the brightness of each color of red, blue, and green light is changed in a trapezoidal shape, and their phases are shifted by 120 degrees and superimposed, and it is always one of red, blue, and green. is the light with the maximum brightness,
The control unit creates a color image from the amount of light received for each wavelength of the pattern light reflected by the measurement target and received by the first light receiving unit, and from the created color image, displays a red image for each pixel. , a three-dimensional measuring device that creates the multivalued image by obtaining maximum brightness values of blue and green. The three-dimensional measuring device according to claim 9 ,
The pattern light changes the brightness of each color of red, blue, and green light using a sine wave, and superimposes the light by shifting the phase by 120 degrees so that the sum of the brightness of red, blue, and green is always constant. It is a light,
The control unit creates a color image from the amount of light received for each wavelength of the pattern light reflected by the measurement target and received by the first light receiving unit, and from the created color image, displays a red image for each pixel. , a three-dimensional measurement device that creates the multivalued image by acquiring the sum of brightness of blue and green.

Images