JP2020091136A - Projection device and three-dimensional measuring device - Google Patents

Abstract

To provide a projection device and a three-dimensional measuring device which can improve the accuracy of measurement when performing three-dimensional measurement that utilizes a pattern projection method.SOLUTION: The projection device comprises: a light source for emitting prescribed light; a grid unit 20 for converting the light from the light source into a stripe pattern; a projection lens unit for forming an image of the stripe pattern generated by the grid unit 20 on a printed circuit board; and a grid unit movement mechanism 22 for changing the grid unit 20 to be displaced and the phase of the stripe pattern projected to the printed circuit board. The grid unit 20 includes a fixed grid plate 25 and a movable grid plate 26, and a grid plate movement mechanism 27 for causing the movable grind plate 26 to be displaced relatively to the fixed grid plate 25 and changing the cycle of the stripe pattern projected to the printed circuit board.SELECTED DRAWING: Figure 7

Description

The present invention relates to a projection device that projects a predetermined pattern of light when performing three-dimensional measurement using a pattern projection method such as a phase shift method, and a three-dimensional measurement device including the projection device.

Generally, when an electronic component is mounted on a printed circuit board, cream solder is first printed on a predetermined electrode pattern arranged on the printed circuit board. Next, the electronic component is temporarily fixed on the printed board based on the viscosity of the cream solder. After that, the printed circuit board is introduced into a reflow furnace and soldered by performing a predetermined reflow process. Nowadays, it is necessary to inspect the printed state of the cream solder before it is introduced into the reflow furnace, and a three-dimensional measuring device may be used for such inspection.

Conventionally, various three-dimensional measuring devices have been proposed that project a predetermined pattern of light to perform three-dimensional measurement. Among them, a three-dimensional measuring device using the phase shift method is well known.

A three-dimensional measurement device using the phase shift method is a projection device that projects pattern light having a striped light intensity distribution (hereinafter, referred to as “striped pattern”) onto an object to be measured such as a printed circuit board from diagonally above. , And an image pickup device for picking up an image of the measured object on which the stripe pattern is projected.

The projection device includes a light source that emits a predetermined light and a pattern generation unit that converts the light from the light source into a striped pattern, and the striped pattern generated here is projected through a projection optical system including a projection lens or the like. It is projected on the measured object.

Under such a configuration, the phase of the stripe pattern projected on the object to be measured is shifted in a plurality of ways (for example, four ways), and imaging is performed under each of the stripe patterns having different phases, so that a plurality of patterns related to the object to be measured are obtained. Get image data. Then, three-dimensional measurement of the object to be measured is performed based on these image data.

However, some of the measurement targets whose heights are actually measured are high in height and low in height. For example, regarding cream solder, the height of the cream solder printed on a conventional general printed circuit board is usually about 100 μm. Since the power circuit and the like are mounted, the height of the cream solder may be about 300 to 400 μm.

Here, for example, if a three-dimensional measuring device in which the period of the projected stripe pattern is made longer than in the past according to the vehicle printed circuit board is used, the height dynamic range is increased and the vehicle printed circuit board can be measured. However, when this is used for the measurement of the conventional general printed circuit board, the height resolution becomes rough and the measurement accuracy may be deteriorated.

Therefore, in order to make the three-dimensional measuring device versatile, a striped pattern having a long cycle is projected when the degree of unevenness of an object to be measured such as a printed circuit board is large, and a short cycle when the degree of unevenness is small. It is necessary to project a striped pattern according to the degree of unevenness of the measured object, such as projecting a striped pattern.

However, when a conventional grid plate in which a grid pattern is printed on a film or a glass plate is used as the pattern generation unit, the width and pitch of the printed grid pattern cannot be changed, so that the pattern is projected onto the measured object. The stripe pattern is constant.

Therefore, if an attempt is made to project different stripe patterns depending on the degree of unevenness of the object to be measured by a three-dimensional measuring device using a grid plate, a plurality of grid plates with different widths or pitches of the printed grid patterns are prepared in advance. It is necessary to prepare and use these lattice plates properly according to the degree of unevenness of the measured object. As described above, the three-dimensional measuring device in which the grid plate has to be replaced each time is inconvenient and may cause a decrease in productivity.

On the other hand, as a pattern generation unit, a three-dimensional measurement device using a liquid crystal element in which a plurality of pixels are two-dimensionally arranged in a matrix is also found.

However, since the conventional liquid crystal element has a dark portion between pixels, the generated stripe pattern is microscopically discontinuous, so that the stripe pattern projected on the measured object is assumed. The striped pattern is not formed, and the measurement accuracy of the three-dimensional measurement may be reduced.

On the other hand, in recent years, in order to solve the above problems, a special liquid crystal element is used to change the width and pitch of the lattice pattern according to the degree of unevenness of the object to be measured, and stripe patterns with different periods can be projected. A three-dimensional measuring device is also found (for example, refer to Patent Document 1).

Specifically, the three-dimensional measuring apparatus described in Patent Document 1 forms N stripe-shaped electrodes having a constant pitch and width on a liquid crystal element, and the stripes are formed at a number n of electrodes that is a multiple of 3 or 4. The live electrode is divided into N/n groups, one grating having a sinusoidal intensity distribution is created for each group, and one cycle of the sinusoidal wave is n or the like according to the number of electrodes n. And a liquid crystal drive signal corresponding to the sum of the amplitude of the sine wave of each divided region and the bias strength of the sine wave is applied to each of the stripe electrodes to obtain the sine wave strength. N/n grid patterns having a distribution are generated, and a voltage of the liquid crystal drive signal to be applied to the stripe electrodes is applied in units of a cycle obtained by dividing one cycle of the grid pattern into three or four. Is sequentially changed, the phase of the lattice pattern is shifted by 2π/3 or π/2 pitch, and the number n of electrodes is changed to form a lattice pattern suitable for the surface shape of the object to be measured. Is configured.

JP, 11-83454, A

However, the configuration according to Patent Document 1 requires the special liquid crystal element described above, which may increase the manufacturing cost of the projection apparatus.

Further, since the liquid crystal element passes through the polarization filter, the stripe pattern projected on the measured object may be dark. As a result, accurate luminance image data cannot be acquired, and the measurement accuracy of the three-dimensional measurement may decrease.

The above problem is not limited to three-dimensional measurement of cream solder or the like printed on a printed circuit board, but is inherent in other three-dimensional measurement fields. Of course, the problem is not limited to the phase shift method.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a projection apparatus and a three-dimensional measurement apparatus capable of improving the measurement accuracy when performing three-dimensional measurement using the pattern projection method. To do.

Hereinafter, each means suitable for solving the above-mentioned problems will be described by itemizing. In addition, the action and effect peculiar to the corresponding means will be additionally described as needed.

Means 1. A projection device for projecting a predetermined pattern light onto the object to be measured when performing three-dimensional measurement of the object to be measured (for example, a printed circuit board),
A light source that emits predetermined light,
A pattern generation unit that converts the light incident from the light source into pattern light and emits the light.
A projection optical system for forming an image of the pattern light emitted from the pattern generation unit on the object to be measured,
The pattern generation unit,
A plurality of grid members having a grid pattern in which a light-transmitting portion that transmits light with a predetermined transmittance and a light-shielding portion that blocks at least a part of light are arranged alternately in a first direction (for example, a horizontal direction), While being arranged to face each other in a second direction (for example, a vertical direction) orthogonal to one direction,
By providing a grid moving means capable of changing the relative positional relationship of the plurality of grid members with respect to the first direction,
A projecting device, characterized in that the cycle of the pattern light projected onto the object to be measured can be changed.

The "lattice member" is, for example, one in which a lattice pattern is printed (deposited) on a flat or film-shaped substrate made of a translucent material such as glass or acrylic resin, or an opaque resin or metal. Those in which a lattice pattern is formed by processing the above and forming openings such as slits are included.

According to the above means 1, by configuring the pattern generation unit that converts the light from the light source into the pattern light using a plurality of grating members, it is possible to project the pattern light that is brighter than when a liquid crystal grating or the like is used. Become.

Further, by providing the grating moving means for changing the relative positional relationship of the plurality of grating members, it is possible to change the cycle (pitch) of the pattern light projected on the object to be measured without replacing the grating member. ..

Furthermore, since an inexpensive optical member such as an existing lattice plate in which a lattice pattern is printed on a substrate such as a glass plate can be used, when an expensive optical control element such as a liquid crystal element is used as the pattern generation unit. It is possible to suppress the manufacturing cost of the pattern generation unit as compared with the above.

In addition, unlike the case where an existing liquid crystal element or the like is used, it is not necessary to control the pixel, the control can be simplified, and the generated pattern light becomes microscopically discontinuous. Since this is not the case, it is possible to project a more ideal pattern light onto the object to be measured.

Means 2. The projection device according to means 1, wherein the grid patterns formed on the plurality of grid members are the same.

According to the above means 2, by using a plurality of lattice members having the same lattice pattern, it is possible to simplify the configuration of the pattern generation unit, simplify the movement control of the lattice member, and suppress the increase in manufacturing cost. it can.

Here, "the same lattice pattern" means that the width of the light transmitting portion in the first direction is the same, the width of the light shielding portion in the first direction is the same, the first direction. It means that the ratio of the light-transmitting portion and the light-shielding portion in is the same, and the formation pitch of the light-transmitting portion and the light-shielding portion in the first direction is the same.

It is preferable that the ratios of the light-transmitting portion and the light-shielding portion in the synthetic lattice pattern in which the lattice patterns of a plurality of lattice members are overlapped are completely the same, but they may be substantially the same. If they are substantially the same, it is possible to generate pattern light with sufficient accuracy for performing three-dimensional measurement using the pattern projection method.

Means 3. The pattern generation unit,
A light-shielding portion of the lattice pattern in one of the two lattice members facing each other in the second direction and a light-shielding portion of the lattice pattern in the other lattice member are continuous in the first direction. By arranging the two grating members, it is possible to generate long-period pattern light,
By arranging the two lattice members such that the light shielding portion of the lattice pattern of the one lattice member and the light shielding portion of the lattice pattern of the other lattice member are separated in the first direction, 3. The projection apparatus according to means 1 or 2, which is configured to be able to generate periodic pattern light.

According to the above means 3, the pattern light having a long period in which the dark portion of the pattern light generated by the light shielding portion of the one lattice member and the dark portion of the pattern light generated by the light shielding portion of the other lattice member are continuous, Switching between two types of pattern light of a short cycle, in which the dark portion of the pattern light generated by the light shielding portion of one grating member and the dark portion of the pattern light generated by the light shielding portion of the other grating member are separated from each other Can be projected.

Means 4. The pattern generation unit,
An end position on one end side in the first direction of the light shielding portion of the grid pattern in the one grid member and an end position on the other end side in the first direction of the light shielding portion of the grid pattern in the other grid member are first. 4. The projection apparatus according to means 3, wherein the two grating members are arranged so as to be at the same position in the direction so that the long-period pattern light can be generated.

According to the above means 4, it is possible to make the ratio of the bright portion and the dark portion the same for both the long-period pattern light and the short-period pattern light. As a result, it becomes possible to project more ideal pattern light onto the object to be measured.

Means 5. The pattern generation unit,
The predetermined range including one end in the first direction of the light shielding portion of the lattice pattern in the one grid member, and the predetermined range including the other end in the first direction of the light shielding portion of the grid pattern in the other lattice member are 4. The projection apparatus according to means 3, wherein the two grating members are arranged so as to overlap in the first direction so that the long-period pattern light can be generated.

According to the above means 5, the light-shielding portions of the two lattice members facing each other are partially overlapped with each other, so that the leakage of light from between the both light-shielding portions can be reduced. As a result, it becomes possible to project more ideal pattern light onto the object to be measured.

Means 6. Any one of the means 1 to 5 characterized in that the plurality of lattice members are constituted by one fixed lattice member and at least one movable lattice member provided so as to be relatively displaceable with respect to the fixed lattice member. The projection device according to claim 1.

According to the above means 6, the movement control of the grating member can be simplified, and the projection position (projection reference position) of the pattern light can be stabilized by the fixed grating member.

Means 7. 7. The projection device according to any one of means 1 to 6, wherein the light shielding portion is composed of a plurality of portions having different transmittances.

According to the above-mentioned means 7, between the portion having a high transmittance (for example, the light transmitting portion) and the portion having a low transmittance (for example, the portion having the lower transmittance in the light shielding portion), the transmittance is medium. A site can be provided, and more ideal pattern light can be projected onto the object to be measured.

Means 8. 8. The projection device according to any one of means 1 to 7, wherein pattern light having a striped (eg, sinusoidal) light intensity distribution can be projected as the pattern light.

According to the above means 8, the three-dimensional measurement by the phase shift method can be performed by projecting the pattern light having the striped light intensity distribution. As a result, it is possible to improve the measurement accuracy of the three-dimensional measurement.

In the configuration such as the phase shift method in which the three-dimensional measurement is performed based on the difference in the brightness value of the plurality of image data acquired by capturing under the pattern light having different phases, even if the error in the brightness value is small, , The measurement accuracy may be greatly affected. Therefore, under the configuration according to the present means, the action and effect of each of the above means will be more successful. In particular, pattern light having a sinusoidal light intensity distribution is likely to collapse the light intensity distribution (waveform), and thus high projection accuracy is required.

Means 9. A projection device according to any one of means 1 to 8;
An image capturing unit capable of capturing an image of a predetermined range of the measured object onto which the pattern light is projected;
A three-dimensional measuring device comprising: an image processing unit capable of performing three-dimensional measurement of the object to be measured based on the image data captured and acquired by the image capturing unit.

According to the means 9, the three-dimensional measurement can be performed by using the pattern light projected from the projection device according to any one of the means 1 to 8. Normally, when performing three-dimensional measurement using the pattern projection method, the light emitted from a predetermined light source is converted into a predetermined pattern light in the pattern generation unit and projected onto the object to be measured through the projection optical system. To do. Then, the object to be measured onto which the pattern light is projected is imaged by the image pickup means, and the three-dimensional measurement of the object to be measured is performed based on the acquired image data.

More specifically, as a three-dimensional measurement device that performs three-dimensional measurement by the phase shift method using the pattern light projected from the projection device according to the above means 8,
"A projection device according to means 8,
An image capturing unit capable of capturing an image of a predetermined range of the measured object onto which the pattern light is projected;
Pattern light displacing means for changing the relative positional relationship (phase) between the pattern light projected by the projection device and the object to be measured;
In a state where the relative positional relationship between the pattern light and the measured object is different, the measured object is related to the measured object by a phase shift method based on a plurality of image data of the measured object captured and captured by the imaging unit. A three-dimensional measuring apparatus, comprising: an image processing unit capable of performing three-dimensional measurement. Is given as an example.

Examples of the "measurement object" include a printed circuit board on which cream solder is printed. That is, by using the projection device described in each of the above means, it is possible to perform three-dimensional measurement of the cream solder printed on the printed circuit board. As a result, in the inspection of the cream solder, the quality of the cream solder can be judged based on the measured value. Therefore, in such an inspection, the effects of each of the above-described means are exhibited, and it is possible to accurately determine the quality. As a result, it is possible to improve the inspection accuracy in the solder printing inspection device.

It is a schematic diagram which shows schematic structure of a board|substrate inspection apparatus. It is a plane schematic diagram which shows schematic structure of a printed circuit board. It is a cross-sectional schematic diagram of a printed circuit board. It is a schematic diagram which shows the aspect of the striped pattern projected on the printed circuit board. It is a schematic diagram which shows schematic structure of a projection apparatus. It is a block diagram which shows the electric constitution of a board|substrate inspection apparatus. It is a schematic diagram which shows schematic structure of a lattice unit. It is a figure for demonstrating the change of the relative positional relationship of a fixed grating board and a movable grating board, (a) is a model which shows the relative positional relationship of a fixed grating board and a movable grating board at the time of projecting a fringe pattern of a long period. FIG. 3B is a perspective view schematically showing a relative positional relationship between the fixed lattice plate and the movable lattice plate when projecting a short-period stripe pattern. FIG. 6 is a diagram for explaining a change in relative positional relationship between the fixed grid plate and the movable grid plate, and FIG. 6A shows a relative positional relationship between the fixed grid plate and the movable grid plate when projecting a long-period fringe pattern. It is a schematic diagram and (b) is a schematic diagram which shows the relative positional relationship of a fixed lattice plate and a movable lattice plate at the time of projecting a striped pattern of a short period. It is a figure for demonstrating the change of the relative positional relationship of the fixed grid plate and movable grid plate in 2nd Embodiment, Comprising: (a) is a fixed grid plate and movable grid plate at the time of projecting a long period stripe pattern. It is a schematic diagram which shows a relative positional relationship, and (b) is a schematic diagram which shows a relative positional relationship between a fixed grating plate and a movable grating plate when projecting a striped pattern of a short cycle. It is a figure for demonstrating the change of the relative positional relationship of a fixed grid plate and a movable grid plate in 3rd Embodiment, Comprising: (a) is a fixed grid plate and a movable grid plate at the time of projecting a long period stripe pattern. It is a schematic diagram which shows a relative positional relationship, and (b) is a schematic diagram which shows a relative positional relationship between a fixed grating plate and a movable grating plate when projecting a striped pattern of a short cycle. It is a figure for demonstrating the change of the relative positional relationship of the fixed grid plate and movable grid plate in 4th Embodiment, Comprising: (a) is a fixed grid plate at the time of projecting a long period stripe pattern, and a movable grid plate. It is a schematic diagram which shows a relative positional relationship, and (b) is a schematic diagram which shows a relative positional relationship between a fixed grating plate and a movable grating plate when projecting a striped pattern of a short cycle. It is a figure for demonstrating the change of the relative positional relationship of a fixed grid plate and a movable grid plate in 5th Embodiment, Comprising: (a) is a fixed grid plate and a movable grid plate of a long period stripe pattern is projected. It is a schematic diagram which shows a relative positional relationship, and (b) is a schematic diagram which shows a relative positional relationship between a fixed grating plate and a movable grating plate when projecting a striped pattern of a short cycle. It is a figure for demonstrating the change of the relative positional relationship of a fixed lattice plate and a movable lattice plate in 6th Embodiment, Comprising: (a) is a fixed lattice plate and a movable lattice plate at the time of projecting a long period stripe pattern. It is a schematic diagram which shows a relative positional relationship, and (b) is a schematic diagram which shows a relative positional relationship between a fixed grating plate and a movable grating plate when projecting a striped pattern of a short cycle.

[First Embodiment]
Hereinafter, an embodiment will be described with reference to the drawings. First, the configuration of the printed circuit board 1 which is the object to be measured in this embodiment will be described in detail (see FIGS. 2 and 3). FIG. 2 is a schematic plan view showing a schematic configuration of the printed board 1. FIG. 3 is a schematic sectional view of the printed circuit board 1.

As shown in FIGS. 2 and 3, the printed circuit board 1 is formed by forming an electrode pattern 3A made of copper foil and a land 3B on the surface of a flat base substrate 2 made of glass epoxy resin or the like. A resist film 4 is coated on the surface of the base substrate 2 except the land 3B and the vicinity thereof. Then, the solder paste 5 is printed on the land 3B.

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

Next, the board inspection apparatus 10 that constitutes the three-dimensional measurement apparatus according to this embodiment will be described in detail (see FIG. 1 ). FIG. 1 is a schematic diagram showing a schematic configuration of the board inspection apparatus 10. In the following description, the horizontal direction of the paper surface of FIG. 1 will be referred to as the “X-axis direction”, the front-back direction of the paper surface will be referred to as the “Y-axis direction”, and the vertical direction of the paper surface (vertical direction) will be referred to as the “Z-axis direction”.

The board inspection device 10 is a solder printing inspection device that inspects the printing state of the cream solder 5 printed on the printed board 1. The board inspection device 10 includes a transfer mechanism 11 that transfers and positions the printed board 1, an inspection unit 12 that inspects the printed board 1, and a drive control of the transfer mechanism 11 and the inspection unit 12. The control device 13 (see FIG. 6) for performing various controls, image processing, and arithmetic processing in the inside.

The transport mechanism 11 includes a pair of transport rails 11a arranged along the transport direction of the printed circuit board 1 (Y-axis direction), an endless conveyor belt 11b rotatably disposed with respect to each transport rail 11a, The controller 13 includes drive means (not shown) such as a motor for driving the conveyor belt 11b, and a chuck mechanism (not shown) for positioning the printed circuit board 1 at a predetermined position.

Under the above configuration, the printed circuit board 1 carried into the board inspection apparatus 10 has both side edges in the width direction (X-axis direction) orthogonal to the carrying direction inserted into the carrying rails 11a and on the conveyor belt 11b. Placed. Then, the conveyor belt 11b starts operating, and the printed circuit board 1 is conveyed to a predetermined inspection position. When the printed circuit board 1 reaches the inspection position, the conveyor belt 11b stops and the chuck mechanism operates. By the operation of the chuck mechanism, the conveyor belt 11b is pushed up, and both side edges of the printed circuit board 1 are clamped by the conveyor belt 11b and the upper side of the transport rail 11a. As a result, the printed circuit board 1 is positioned and fixed at the inspection position. When the inspection is completed, the fixing by the chuck mechanism is released, and the conveyor belt 11b starts operating. As a result, the printed board 1 is unloaded from the board inspection apparatus 10. Of course, the configuration of the transport mechanism 11 is not limited to the above-mentioned form, and other configurations may be adopted.

The inspection unit 12 is arranged above the transport path of the printed circuit board 1 (a pair of transport rails 11a). The inspection unit 12 projects a stripe pattern W (see FIG. 4) obliquely from above onto a predetermined inspection range on the printed board 1, and a predetermined area on the printed board 1 onto which the stripe pattern W is projected. A camera 15 as an image pickup unit that images the inspection range from directly above, an X-axis moving mechanism 16 (see FIG. 6) that enables movement in the X-axis direction, and a Y-axis that enables movement in the Y-axis direction. A moving mechanism 17 (see FIG. 6) is provided, and drive control is performed by the control device 13.

As shown in FIG. 2, the predetermined inspection range on the printed circuit board 1 includes a plurality of areas (previously set on the printed circuit board 1 with the size of the imaging field of view (imaging range) K of the camera 15 as one unit. It is one of the inspection ranges “1” to “15”).

The control device 13 drives and controls the X-axis moving mechanism 16 and the Y-axis moving mechanism 17 so that the inspection unit 12 (imaging field of view K) is positioned and fixed at the inspection position in an arbitrary inspection range on the printed circuit board 1. Can be moved to the upper position. Then, while sequentially moving the inspection unit 12 to a plurality of inspection ranges set on the printed circuit board 1, the inspection processing for each inspection range is executed, thereby performing the solder print inspection for the entire printed circuit board 1. It is configured to do.

As shown in FIG. 5, the projection device 14 includes a light source 19 that emits predetermined light, a lattice unit 20 as a pattern generation unit that converts the light from the light source 19 into a striped pattern W, and the lattice unit 20 that generates the light. A projection lens unit 21 as a projection optical system that forms an image of the striped pattern W formed on the printed circuit board 1, and a grating for displacing the grating unit 20 to change the phase of the striped pattern W projected on the printed circuit board 1. A unit moving mechanism 22 (see FIG. 7) is provided, and drive control is performed by the control device 13.

The projection device 14 is arranged such that its optical axis J1 is parallel to the X-Z plane and is inclined by a predetermined angle α (for example, 30°) with respect to the Z-axis direction.

The light source 19 is composed of a halogen lamp that emits white light. The light emitted from the light source 19 is incident on the grating unit 20 along the optical axis J1 in the state of being collimated through a pretreatment lens group or the like (not shown).

Here, the configuration of the lattice unit 20 will be described in detail with reference to FIG. 7. FIG. 7 is a schematic diagram showing a schematic configuration of the lattice unit 20.

When describing the lattice unit 20 alone, for convenience, the horizontal direction of the paper of FIG. 7 is referred to as the “X′ axis direction”, the longitudinal direction of the paper is referred to as the “Y′ axis direction”, and the vertical direction of the paper is referred to as the “Z′ axis. Direction”.

However, the coordinate system (X′, Y′, Z′) for explaining the lattice unit 20 alone and the coordinate system (X, Y, Z) for explaining the substrate inspection apparatus 10 (projection apparatus 14) as a whole are Different coordinate system. Here, the “X′ axis direction” corresponds to the “first direction” in the present embodiment, and the “Z′ axis direction” corresponds to the “second direction”.

As shown in FIG. 7, the lattice unit 20 includes a main body case portion 24 forming an outer shell thereof, a fixed lattice plate 25 as a fixed lattice member provided in the main body case portion 24, and a movable lattice member movable. A lattice plate 26, and a lattice plate moving mechanism (pattern period changing mechanism) 27 for changing the period of the stripe pattern W projected on the printed circuit board 1 by displacing the movable lattice plate 26 relative to the fixed lattice plate 25. Is equipped with. The lattice plate moving mechanism 27 constitutes the lattice moving means in this embodiment.

The main body case portion 24 has a light-transmitting property, and a front surface thereof serves as an entrance surface 20a of the grating unit 20 that allows the light emitted from the light source 19 to enter the inside of the grating unit 20, and a back surface thereof serves as the grating unit 20. It becomes the emission surface 20b of the grating unit 20 that emits the light (stripe pattern W) that has passed through the inside.

The fixed grating plate 25 and the movable grating plate 26 face each other with respect to their own optical axis J3 (the vertical direction in FIG. 7, which is the Z′ axis direction) orthogonal to the entrance surface 20a and the exit surface 20b of the grating unit 20. It is arranged.

The fixed lattice plate 25 is fixed to the main body case portion 24 such that it cannot be displaced relative to the main body case portion 24. On the other hand, the movable grating plate 26 is provided so as to be displaceable along the X'axis direction (the left-right direction in FIG. 7) orthogonal to the optical axis J3.

The lattice plate moving mechanism 27 is provided on one side (left side in FIG. 7) of the movable lattice plate 26 in the X′-axis direction and serves as an urging means for urging the movable lattice plate 26 toward the other side (right side in FIG. 7). The control device 13 includes a spring member 27a and a solenoid 27b that is provided on the other side of the movable lattice plate 26 in the X′-axis direction and that slides the movable lattice plate 26 along the X′-axis direction. Drive controlled.

On each of the lattice plates 25 and 26, a light-transmitting portion 31 that transmits light with a predetermined transmittance and a light-shielding portion 32 that shields at least a part of light are arranged so as to be alternately arranged in the X′-axis direction. A lattice pattern 30 is formed [see FIGS. 8(a) and 8(b)]. 8A and 8B are schematic diagrams for explaining changes in the relative positional relationship between the fixed lattice plate 25 and the movable lattice plate 26.

Specifically, in each of the lattice plates 25 and 26 of the present embodiment, the light shielding portion 32 is provided on the base material 28 formed in a flat plate shape or a film shape with a predetermined light transmitting material (for example, glass or acrylic resin). The grid pattern 30 is formed by printing (evaporating) at predetermined intervals in the X′-axis direction.

In the present embodiment, the grid plates 25 and 26 are arranged so that the printed surface (grid surface) of the grid pattern 30 faces the light source 19 side, that is, the light incident side [FIG. b)]]. However, in FIG. 7, for the sake of clarity, not only the surface of each grid plate 25, 26 but also the entire thickness direction of each grid plate 25, 26 is shown in black for the portion corresponding to the light shielding portion 32. (The same applies to FIGS. 9 to 14 described later).

Further, in the present embodiment, the grid patterns 30 formed on the fixed grid plate 25 and the movable grid plate 26 are the same. That is, in both grid plates 25 and 26, the width of the light transmitting portion 31 in the X′ axis direction is the same, the width of the light shielding portion 32 in the X′ axis direction is the same, and the light transmitting portion 31 and the light shielding portion in the X′ axis direction are light shielded. The ratio of the portions 32 is the same, and the light-transmitting portions 31 and the light-shielding portions 32 are formed at the same pitch in the X′-axis direction.

Specifically, in each of the lattice plates 25 and 26 according to the present embodiment, the width of the light transmitting portion 31 in the X′ axis direction is “600 (30×20) μm” and the width of the light shielding portion 32 in the X′ axis direction is. It is set to “200 (10×20) μm”, and the ratio of the light transmitting portion 31 and the light shielding portion 32 is “3:1” [see FIGS. 9(a) and 9(b)]. In addition, the notation mode of the widths of the light transmitting part 31 and the light shielding part 32 in FIG. 9 is a notation mode that is easy to compare with other embodiments shown in FIGS. 10 to 14 described later.

With the above configuration, the lattice unit 20 can switch the generated stripe pattern W to two kinds of stripe patterns W having different periods (stripe pitches).

Specifically, in the present embodiment, two types of stripe patterns W, a first stripe pattern W1 having a first cycle of 800 μm (height resolution 8 μm) and a second stripe pattern W2 having a second cycle of 400 μm (height resolution 4 μm). Can be switched to. The “first cycle 800 μm” corresponds to the “long cycle” in the present embodiment, and the “second cycle 400 μm” corresponds to the “short cycle”.

Here, in the case of generating the first striped pattern W1 having a long period, the lattice plate moving mechanism 27 is drive-controlled to slide the movable lattice plate 26 in the X′-axis direction, as shown in FIG. Then, align the other end (left end) of the light shield 32 on the movable lattice plate 26 side with the other end (left end) of the light shield 32 on the fixed lattice plate 25 side with the position of one end (right end) on the X′ axis side. To do.

As a result, in the grating unit 20, the width of the light transmitting portion in the X′-axis direction is “400 (20×20) μm”, which is a composite grating pattern in which the grating patterns 30 of both grating plates 25 and 26 are superposed. A virtual lattice pattern is formed in which the width of the light-shielding portion in the direction of the axis is “400 (20×20) μm” and the ratio of the light-transmitting portion to the light-shielding portion is “1:1”.

Then, the first stripe pattern W1 having the first period of 800 μm is generated by the synthetic lattice pattern. By projecting the first striped pattern W1 on the printed circuit board 1, the cream solder 5 in the height range of 0 μm to 800 μm can be measured with an accuracy of “8 μm”.

It should be noted that the light passing through the grating is not a perfect parallel light, and the "bright part" and "dark part" of the projected stripe pattern are caused by the diffraction effect at the boundary between the light transmitting part and the light shielding part. An intermediate gradation area is generated at the boundary. Therefore, the striped pattern W projected on the printed circuit board 1 becomes pattern light having a sinusoidal light intensity distribution along the direction (X axis direction) orthogonal to the transport direction (Y axis direction) of the printed circuit board 1. (See Figure 4).

However, in FIG. 4 and FIG. 9, for simplification, the intermediate gradation region is omitted, and the striped pattern W is illustrated as a bright and dark binary striped pattern. Therefore, the notation of the width of the bright portion and the dark portion of the striped pattern W in FIG. 9 indicates the width of the light-transmitting portion and the light-shielding portion in the composite lattice pattern (the same applies to FIGS. 10 to 14 described later).

On the other hand, when the second striped pattern W2 having a short cycle is generated, the lattice plate moving mechanism 27 is drive-controlled to slidably displace the movable lattice plate 26 in the X′-axis direction, as shown in FIG. 9B. The light shielding portion 32 on the movable lattice plate 26 side is aligned with the central portion of the light transmitting portion 31 on the fixed lattice plate 25 side in the X′-axis direction.

As a result, in the grating unit 20, the width of the light-transmitting portion in the X′-axis direction is “200 (10×20) μm” as a composite grating pattern in which the grating patterns 30 of both the grating plates 25 and 26 are superposed. A virtual lattice pattern is formed in which the width of the light-shielding portion in the “axis direction” is “200 (10×20) μm” and the ratio of the light-transmitting portion to the light-shielding portion is “1:1”.

Then, the second grid pattern W2 having the second cycle of 400 μm is generated by the combined grid pattern. By projecting the second striped pattern W2 on the printed circuit board 1, the cream solder 5 in the height range of 0 μm to 400 μm can be measured with an accuracy of “4 μm”.

In the present embodiment, the example in which the projection magnification of the projection optical system (projection lens unit 21) is set to 1 is shown, but the projection magnification is not limited to this. Depending on the projection magnification, the size of the grid pattern 30 on each grid plate 25, 26 (the size of the composite grid pattern on the emission surface 20b of the grid unit 20) and the size of the stripe pattern W projected on the printed board 1 change. To do.

Further, as shown in FIG. 7, a lattice unit moving mechanism 22 for displacing the lattice unit 20 is provided on one side (left side in FIG. 7) in the X′-axis direction of the lattice unit 20 and the lattice unit 20 is arranged on the other side (see FIG. 7). 7) a spring member 22a as a biasing means for biasing the grid unit 20 and a drive means provided on the other side of the lattice unit 20 in the X'-axis direction and slidingly displacing the lattice unit 20 along the X'-axis direction. And a piezo element 22b, which is driven and controlled by the controller 13. The grating unit moving mechanism 22 constitutes the pattern light displacement means in this embodiment.

Returning to the description of FIG. 5, the projection lens unit 21 has an entrance side lens 35 and an exit side lens 36, and these two lenses 35, 36 are configured as a both-side telecentric optical system (both-side telecentric lens).

Here, the incident side lens 35 condenses the light (stripe pattern W) emitted from the grating unit 20, and has a telecentric structure in which the optical axis J1 and the principal ray are parallel on the incident side.

The exit side lens 36 is for forming an image of the light (stripe pattern W) transmitted through the entrance side lens 35 on the printed board 1, and the optical axis J1 and the principal ray are parallel to each other on the exit side. It has a telecentric structure.

Further, in the projection device 14 according to the present embodiment, the optical axis J1 is set so that the stripe pattern W projected on the printed board 1 is focused in the entire projection range (the same range as the imaging visual field K in the present embodiment). On the other hand, the grating unit 20 (optical axis J3) is set to be inclined (see FIGS. 5 and 7).

Specifically, with respect to the printed circuit board 1, the emission surface (composite grating surface) 20b of the grating unit 20 and the main surface of the projection lens unit 21 are set so as to satisfy the Scheimpflug condition.

Here, the principle of Scheimpflug will be described with reference to FIG. The Scheimpflug principle is that a plane S1 including the exit surface 20b of the grating unit 20 and a plane S2 including the main surface of the projection lens unit 21 are on the same straight line C (a straight line perpendicular to the plane of the paper at the point C on FIG. 5). In the case of intersecting with each other, the object plane S3 onto which the stripe pattern W is projected in focus also intersects on the same straight line C. Therefore, the condition based on the Scheimpflug principle is that the plane S1 including the emission surface 20b of the grating unit 20, the plane S2 including the main surface of the projection lens unit 21, and the surface (projection surface) of the printed circuit board 1 are used. That is, the included planes S3 intersect with each other on the same straight line C.

With the above configuration, in the projection device 14, the light emitted from the light source 19 enters the entrance surface 20a of the grating unit 20. The light transmitted through the lattice unit 20 is emitted as a striped pattern W from the emission surface 20b of the lattice unit 20. Then, it is projected onto the printed circuit board 1 via the projection lens unit 21. As a result, in the present embodiment, as shown in FIG. 4, the stripe pattern W parallel to the transport direction (Y-axis direction) of the printed circuit board 1 is projected.

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

The imaging lens unit 15b is composed of a both-side telecentric lens (both-side telecentric optical system) integrally including an object-side lens, an aperture stop, an image-side lens, and the like. However, in FIG. 1, the imaging lens unit 15b is illustrated as one lens for simplification.

Here, the object side lens collects the reflected light from the printed circuit board 1 and has a telecentric structure in which the optical axis J2 and the principal ray are parallel on the object side. The image-side lens is used to form an image of the light transmitted through the aperture stop from the object-side lens on the light-receiving surface of the image sensor 15a, and has a telecentric structure in which the optical axis J2 and the principal ray are parallel on the image side. Have.

The image data captured and acquired by the camera 15 is converted into a digital signal inside the camera 15 at any time, and then input to the control device 13 in the form of a digital signal and stored in an image data storage device 44 described later. It Then, the control device 13 executes image processing, arithmetic processing, and the like, which will be described later, based on the image data. The control device 13 constitutes the image processing means in this embodiment.

Next, the electrical configuration of the control device 13 will be described with reference to FIG. FIG. 6 is a block diagram showing the electrical configuration of the board inspection apparatus 10.

As shown in FIG. 6, the control device 13 includes a microcomputer 41 that controls the entire board inspection device 10, an input device 42 as an “input unit” including a keyboard, a mouse, a touch panel, a CRT, a liquid crystal, and the like. A display device 43 as a “display unit” having a display screen, an image data storage device 44 for storing image data captured by the camera 15 and the like, a three-dimensional measurement result obtained based on the image data, and the like. A calculation result storage device 45 for storing various calculation results, a setting data storage device 46 for storing various information such as Gerber data in advance, and the like.

The microcomputer 41 includes a CPU 41a as an arithmetic means, a ROM 41b for storing various programs, a RAM 41c for temporarily storing various data such as arithmetic data and input/output data, and the like electrically connected to the above-mentioned devices 42 to 46. It is connected to the. Further, it has a function of controlling input/output of various data and signals with the respective devices 42 to 46 and the like.

The setting data storage device 46 stores a plurality of inspection ranges set on the printed circuit board 1, information regarding the moving order of the imaging visual field K of the camera 15 with respect to the inspection ranges, and the like. Here, the “moving order of the imaging field of view K” defines in what order the imaging field of view K of the camera 15 is moved with respect to a plurality of inspection ranges set on the printed circuit board 1.

The plurality of inspection ranges on the printed circuit board 1 and the moving order of the imaging visual field K for these are set automatically in advance by a predetermined program based on Gerber data or the like or manually by an operator.

For example, in the example shown in FIG. 2, the movement order (inspection order) of the imaging visual field K is set with the inspection range in the upper right corner as a starting point. In FIG. 2, the area surrounded by the chain double-dashed line frame indicates the imaging visual field K (inspection range), and the circled numbers “1” to “15” in the frame indicate the inspection order. Further, in FIG. 2, the moving direction (moving path) of the imaging visual field K is indicated by a dotted arrow.

Next, the inspection routine of the printed board 1 performed by the board inspection device 10 will be described in detail. This inspection routine is executed by the control device 13 (microcomputer 41).

As described above, when the printed circuit board 1 carried into the board inspection device 10 is positioned and fixed at a predetermined inspection position, the control device 13 first executes the position detection process of the printed circuit board 1.

More specifically, the control device 13 detects a positioning mark (not shown) provided on the printed circuit board 1, detects the position information (coordinates) of the detected mark, and the position information of the mark stored in the Gerber data. Based on the (coordinates), position information (tilt, position shift, etc.) of the printed circuit board 1 is calculated. As a result, the position detection process of the printed circuit board 1 is completed. Then, based on the position information of the printed circuit board 1, a correction process for correcting the deviation of the relative positional relationship between the inspection unit 12 (camera 15) and the printed circuit board 1 is executed.

After that, according to the inspection order stored in the setting data storage device 46, a movement process for moving the inspection unit 12 to the position corresponding to the “1”th inspection range on the printed circuit board 1 is executed.

During this time, the control device 13 executes a process of adjusting the cycle of the stripe pattern W projected on the “1”-th inspection range to a cycle corresponding to the inspection range based on the Gerber data stored in the setting data storage device 46. To do.

As shown in FIG. 2, in the present embodiment, the “1”-th inspection range is the control circuit unit PB, and therefore the second stripe pattern W2 having a short cycle is set here.

When the moving process of the inspection unit 12 is completed and the imaging visual field K of the camera 15 is adjusted to the "1"th inspection range on the printed circuit board 1, the second stripe pattern W2 is projected from the projection device 14 to print the printed circuit board. The inspection process related to the “1”-th inspection range above 1 is executed. Details of the inspection process will be described later (the same applies to inspection processes related to other inspection ranges).

After that, when the inspection process related to the “1”-th inspection range on the printed circuit board 1 is completed, the inspection unit 12 is moved to the “2”-th inspection on the printed circuit board 1 in accordance with the inspection order stored in the setting data storage device 46. The movement process of moving to the position corresponding to the range is started.

During this time, the control device 13 executes the process of adjusting (changing) the cycle of the stripe pattern W projected on the “2”-th inspection range to the cycle corresponding to the inspection range, as described above.

As shown in FIG. 2, in the present embodiment, the “2”-th inspection range is the power circuit unit PA, so here, the first stripe pattern W1 having a long period is set.

When the moving process of the inspection unit 12 is completed and the imaging visual field K of the camera 15 is adjusted to the “2”-th inspection range on the printed board 1, the projection device 14 projects the first stripe pattern W1 to print the printed board. The inspection process related to the “2”-th inspection range above 1 is executed.

After that, when the inspection process related to the "2"th inspection range on the printed circuit board 1 is completed, the inspection unit 12 is moved to the "3"th inspection range on the printed circuit board 1 in accordance with the inspection order stored in the setting data storage device 46. The movement process of moving to the position corresponding to the range is started.

Similarly, thereafter, the inspection processing is executed for the “3”th to “15th” inspection ranges on the printed circuit board 1 by the stripe pattern W (first stripe pattern W1 or second stripe pattern W2) corresponding to the inspection range. As a result, the solder printing inspection for the entire printed circuit board 1 is completed.

Next, the inspection process performed in each inspection range of the printed circuit board 1 will be described. The inspection process is executed by the control device 13 (microcomputer 41).

In the present embodiment, for each inspection range, while changing the phase of the stripe pattern W projected from the projection device 14, the imaging processing is performed four times under the stripe pattern W having different phases, so that the light intensity distribution Acquire four different types of image data. The details will be described below.

As described above, the control device 13 first drives and controls the X-axis moving mechanism 16 and the Y-axis moving mechanism 17 to move the inspection unit 12, so that the imaging visual field K of the camera 15 falls within a predetermined inspection range of the printed circuit board 1. Align. At the same time, the movement of the grating unit 20 of the projection device 14 is controlled, and the position of the grating unit 20 is set to a predetermined reference position (for example, the position of the phase “0°”).

When the positioning of the lattice unit 20 is completed, the control device 13 causes the light source 19 of the projection device 14 to emit light, projects a predetermined stripe pattern W (first stripe pattern W1 or second stripe pattern W2), and causes the camera 15 to operate. The drive is controlled to execute the first imaging process under the stripe pattern W.

After that, the control device 13 turns off the light source 19 and executes the moving process of the grating unit 20 at the same time as the end of the first imaging process under the predetermined stripe pattern W. Specifically, the position of the lattice unit 20 is moved from the reference position to the second position where the phase of the stripe pattern W is shifted by a quarter pitch (90°).

When the moving process of the lattice unit 20 is completed, the control device 13 causes the light source 19 to emit light, projects a predetermined striped pattern W, and drives and controls the camera 15 for the second time under the striped pattern W. The imaging process is executed.

After that, by repeating the same process, four types of image data having different light intensity distributions are acquired under the stripe pattern W having different phases by 90° (each quarter pitch). This makes it possible to acquire four types of image data in which the phase of the fringe pattern W having a sinusoidal light intensity distribution is shifted by 90°.

Then, the control device 13 performs three-dimensional measurement of the cream solder 5 (height of each coordinate) by a known phase shift method based on the four types of image data (four luminance values of each coordinate) acquired as described above. (Measurement) is performed, and the measurement result is stored in the calculation result storage device 45.

Here, a known phase shift method will be described. Light intensities (luminances) I0, I1, I2, and I3 at predetermined coordinate positions on the printed circuit board 1 in the above four types of image data are expressed by the following equations (1), (2), (3), and (4), respectively. be able to.

I0=αsinθ+β (1)
I1=αsin(θ+90°)+β=αcos θ+β (2)
I2=αsin(θ+180°)+β=−αsinθ+β (3)
I3=αsin(θ+270°)+β=−αcos θ+β (4)
However, α: gain, β: offset, θ: phase of fringe pattern.

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

θ=tan ⁻¹ {(I0-I2)/(I1-I3)} ··· (5)
By using the phase θ calculated in this way, the height (Z) at each coordinate (X, Y) on the printed circuit board 1 can be obtained based on the principle of triangulation.

Next, the control device 13 performs quality determination processing of the printing state of the cream solder 5 based on the three-dimensional measurement result (height data at each coordinate) obtained as described above. Specifically, the control device 13 determines a predetermined height from a height reference plane determined for each inspection range (power circuit unit PA, control circuit unit PB) based on the measurement result of the inspection range obtained as described above. The amount of the printed cream solder 5 is calculated by detecting the printing range of the cream solder 5 that has become longer than the length and integrating the height of each part within this range.

Subsequently, the control device 13 uses the data of the position, the area, the height, or the amount of the cream solder 5 thus obtained as the reference data (gerber data or the like) stored in the setting data storage device 46 in advance. A comparison judgment is made, and whether the print state of the cream solder 5 in the inspection range is good or bad is judged depending on whether or not the comparison result is within the allowable range.

After the acquisition of the four types of image data, the control device 13 moves the inspection unit 12 to the next inspection range while the quality determination processing is being performed. Thereafter, the series of processes described above is repeatedly performed in all the inspection ranges on the printed circuit board 1, and the solder print inspection for the entire printed circuit board 1 is completed.

As described above in detail, according to the present embodiment, the projection device 14 projects the stripe pattern W onto the printed circuit board 1 and acquires four types of image data in which the phases of the stripe pattern W are different, Three-dimensional measurement of the printed circuit board 1 by the phase shift method is performed based on these image data.

At this time, in this embodiment, the cycle (pitch) of the stripe pattern W projected from the projection device 14 is changed according to the degree of unevenness of the inspection range on the printed circuit board 1. Specifically, two types of stripe patterns W, a long stripe first stripe pattern W1 and a short cycle second stripe pattern W2, are switched and projected.

Particularly, according to the projection device 14 according to the present embodiment, a liquid crystal lattice or the like is used by using the lattice unit 20 (the lattice plates 25 and 26) as a pattern generation unit that converts the light from the light source 19 into the stripe pattern W. A brighter stripe pattern W can be projected than in the case.

Further, by providing the grid plate moving mechanism 27 that changes the relative positional relationship between the two grid plates 25 and 26, the cycle of the stripe pattern W projected on the printed board 1 can be changed without replacing the grid plates 25 and 26. It is possible to change.

Further, in the present embodiment, since inexpensive optical members such as the existing lattice plates 25 and 26 in which the lattice pattern 30 is printed on the substrate 28 such as a glass plate can be used, an expensive optical element such as a liquid crystal element can be used. The manufacturing cost of the pattern generation unit can be suppressed as compared with the case where the control element is used as the pattern generation unit.

In addition, unlike the case where an existing liquid crystal element or the like is used, it is not necessary to control the pixels, the control can be simplified, and the generated stripe pattern W is microscopically discontinuous. Therefore, the more ideal stripe pattern W can be projected onto the printed circuit board 1.

[Second Embodiment]
Next, the second embodiment will be described in detail with reference to FIG. In addition, about the part which overlaps with the said 1st Embodiment, the detailed description is abbreviate|omitted using the same member name and the same code|symbol, and below, focusing on the part different from 1st Embodiment. This will be described (the same applies to the third to sixth embodiments described later).

In the fixed grid plate 25 and the movable grid plate 26 according to the present embodiment, the width of the light transmitting portion 31 in the X′ axis direction is “580 (29×20) μm” and the width of the light shielding portion 32 in the X′ axis direction is ““. 220 (11×20) μm”, and the ratio of the light transmitting portion 31 and the light shielding portion 32 is “29:11” (see FIGS. 10A and 10B).

When the first striped pattern W1 having a long period is generated, the lattice plate moving mechanism 27 is drive-controlled to slide the movable lattice plate 26 in the X′-axis direction, and as shown in FIG. A predetermined range including one end (right end) of the light shield 32 on the fixed grid plate 25 side, and the other end (left end) of the light shield 32 on the movable grid plate 26 side in the X′ axis. Positioning is performed so that the predetermined range overlaps with the X'-axis direction.

As a result, in the grating unit 20, the width of the light transmitting portion in the X′-axis direction is “400 (20×20) μm”, which is a composite grating pattern in which the grating patterns 30 of both grating plates 25 and 26 are superposed. A virtual lattice pattern is formed in which the width of the light-shielding portion in the direction of the axis is “400 (20×20) μm” and the ratio of the light-transmitting portion to the light-shielding portion is “1:1”. Then, the first stripe pattern W1 having the first period of 800 μm is generated by the synthetic lattice pattern.

On the other hand, when the second striped pattern W2 having a short cycle is generated, the lattice plate moving mechanism 27 is drive-controlled to slidably displace the movable lattice plate 26 in the X′-axis direction, as shown in FIG. The light shielding portion 32 on the movable lattice plate 26 side is aligned with the central portion of the light transmitting portion 31 on the fixed lattice plate 25 side in the X′-axis direction.

As a result, in the grating unit 20, the width of the light-transmitting portion in the X′-axis direction is “180 (9×20) μm”, which is a composite grating pattern in which the grating patterns 30 of both grating plates 25 and 26 are superposed. A virtual lattice pattern is formed in which the width of the light-shielding portion in the “axis direction” is “220 (11×20) μm” and the ratio of the light-transmitting portion to the light-shielding portion is “9:11”. Then, the second grid pattern W2 having the second cycle of 400 μm is generated by the combined grid pattern.

As described in detail above, according to this embodiment, the same operational effects as those of the above-described first embodiment are exhibited.

In particular, according to the present embodiment, when the long-period first stripe pattern W1 is generated, a part of the light shielding part 32 on the fixed lattice plate 25 side and a part of the light shielding part 32 on the movable lattice plate 26 side are formed. By overlapping, light leakage can be suppressed. As a result, a more ideal stripe pattern W can be projected onto the printed board 1.

In the present embodiment, when the second striped pattern W2 having a short cycle is generated, the ratio of the light-transmitting portion and the light-shielding portion in the synthetic grating pattern is not “1:1”, but the ratio is not the same. If they are substantially the same as "9:11", it is possible to generate the fringe pattern W having a sinusoidal light intensity distribution with sufficient accuracy for performing three-dimensional measurement by the phase shift method.

[Third Embodiment]
Next, a third embodiment will be described in detail with reference to FIG. In the fixed grid plate 25 and the movable grid plate 26 according to the present embodiment, the width of the light transmitting portion 31 in the X′ axis direction is “600 (30×20) μm” and the width of the light shielding portion 32 in the X′ axis direction is “ 200 (10×20) μm”, and the ratio of the light transmitting portion 31 and the light shielding portion 32 is “3:1” (see FIGS. 11A and 11B).

Then, when the first striped pattern W1 having a long period is generated, the lattice plate moving mechanism 27 is drive-controlled to slide the movable lattice plate 26 in the X′-axis direction, and as shown in FIG. A predetermined range including one end (right end) of the light shield 32 on the fixed grid plate 25 side, and the other end (left end) of the light shield 32 on the movable grid plate 26 side in the X′ axis. Positioning is performed so that the predetermined range overlaps with the X'-axis direction.

As a result, in the grating unit 20, the width of the light-transmitting portion in the X′-axis direction is “420 (21×20) μm”, which is a composite grating pattern in which the grating patterns 30 of both grating plates 25 and 26 are superposed. A virtual lattice pattern is formed in which the width of the light-shielding portion in the “axis direction” is “380 (19×20) μm” and the ratio of the light-transmitting portion to the light-shielding portion is “21:19”. Then, the first stripe pattern W1 having the first period of 800 μm is generated by the synthetic lattice pattern.

On the other hand, when the second striped pattern W2 having a short cycle is generated, the lattice plate moving mechanism 27 is drive-controlled to slidably displace the movable lattice plate 26 in the X′-axis direction, as shown in FIG. The light shielding portion 32 on the movable lattice plate 26 side is aligned with the central portion of the light transmitting portion 31 on the fixed lattice plate 25 side in the X′-axis direction.

As a result, in the grating unit 20, the width of the light-transmitting portion in the X′-axis direction is “200 (10×20) μm” as a composite grating pattern in which the grating patterns 30 of both the grating plates 25 and 26 are superposed. A virtual lattice pattern is formed in which the width of the light-shielding portion in the “axis direction” is “200 (10×20) μm” and the ratio of the light-transmitting portion to the light-shielding portion is “1:1”. Then, the second grid pattern W2 having the second cycle of 400 μm is generated by the combined grid pattern.

As described above in detail, according to this embodiment, the same operational effects as those of the first and second embodiments can be obtained.

[Fourth Embodiment]
Next, a fourth embodiment will be described in detail with reference to FIG. The lattice unit 20 according to this embodiment includes one fixed lattice plate 25 and two movable lattice plates 26. Specifically, the first movable grid plate 26A located above the fixed grid plate 25 and the second movable grid plate 26B located below the fixed grid plate 25 are provided.

In the fixed lattice plate 25 and the movable lattice plate 26 (26A, 26B) according to the present embodiment, the width of the light transmitting portion 31 in the X′ axis direction is “1000 (50×20) μm” and the light shielding portion in the X′ axis direction. The width of 32 is set to “200 (10×20) μm”, and the ratio of the light transmitting portion 31 and the light shielding portion 32 is “5:1” [see FIGS. 12(a) and 12(b)].

When the first striped pattern W1 having a long period is generated, the lattice plate moving mechanism 27 is drive-controlled to slidably displace the first movable lattice plate 26A and the second movable lattice plate 26B in the X′-axis direction. As shown in FIG. 12A, at the position of one end (left end) in the X′-axis direction of the light shield 32 on the fixed grid plate 25 side, the X′ axis of the light shield 32 on the first movable grid plate 26A side is formed. The other end (right end) in the direction is aligned, and at the other end (right end) in the X′-axis direction of the light shield 32 on the fixed grid plate 25 side, the light shield 32 on the second movable grid plate 26B side is located. Align one end (left end) of the X'-axis direction.

As a result, in the grating unit 20, the width of the light transmitting portion in the X′-axis direction is “600 (30×20) μm as a composite grating pattern in which the grating patterns 30 of the three grating plates 25, 26A, and 26B are superposed. , The width of the light-shielding portion in the X′-axis direction is “600 (30×20) μm”, and a virtual lattice pattern in which the ratio of the light-transmitting portion to the light-shielding portion is “1:1” is formed. Then, the first stripe pattern W1 having the first cycle of 1200 μm is generated by the combined grid pattern.

On the other hand, when the second striped pattern W2 having a short cycle is generated, the lattice plate moving mechanism 27 is drive-controlled to slidably displace the first movable lattice plate 26A and the second movable lattice plate 26B in the X′ axis direction. As shown in FIG. 12B, the light shielding portion 32 on the side of the first movable lattice plate 26A is moved from the light shielding portion 32 on the side of the fixed lattice plate 25 to one side (left side) in the X′-axis direction by a predetermined amount [200(10 X 20) μm] and the light shielding portion 32 on the side of the second movable lattice plate 26B is moved from the light shielding portion 32 on the side of the fixed lattice plate 25 to the other side (right side) in the X'-axis direction by a predetermined amount [200 (10×20). ) Μm] Separated.

As a result, in the grating unit 20, a width of the light transmitting portion in the X′-axis direction is “200 (10×20) μm as a composite grating pattern in which the grating patterns 30 of the three grating plates 25, 26A, and 26B are superposed. , A width of the light shielding portion in the X′-axis direction is “200 (10×20) μm”, and a virtual lattice pattern in which the ratio of the light transmitting portion and the light shielding portion is “1:1” is formed. Then, the second grid pattern W2 having the second cycle of 400 μm is generated by the combined grid pattern.

As described in detail above, according to this embodiment, the same operational effects as those of the above-described first embodiment are exhibited. Particularly, according to the present embodiment, by using the three grating plates 25, 26A, and 26B, it is possible to increase the difference in the cycle between the long-period first stripe pattern W1 and the short-period second stripe pattern W2. it can.

[Fifth Embodiment]
Next, a fifth embodiment will be described in detail with reference to FIG. In the fixed grid plate 25 and the movable grid plate 26 according to the present embodiment, the width of the light transmitting portion 31 in the X′-axis direction is “500 (25×20) μm” and the width of the light shielding portion 32 in the X′-axis direction is “ It is set to "300 (15×20) μm", and the ratio of the light transmitting portion 31 and the light shielding portion 32 is "5:3" [see FIGS. 13(a) and 13(b)].

However, the light shielding portion 32 in the present embodiment is composed of a plurality of portions having different transmittances. More specifically, a medium-transmittance portion is provided between the high-transmittance portion (the light-transmitting portion 31) and the low-transmittance portion (the light-shielding portion 32 having the lower transmittance). ing.

Specifically, a high light-shielding portion with a transmittance of 25% is provided in the “100 (5×20) μm” range in the central portion of the light-shielding portion 32 in the X′-axis direction, and the high light-shielding portion is provided on both sides of the high light-shielding portion in the X′-axis direction. In the range of “100 (5×20) μm”, middle light-shielding portions with a transmittance of 50% are provided. On the other hand, the transmissivity of the translucent portion 31 in this embodiment is 100%.

Then, when the first striped pattern W1 having a long period is generated, the lattice plate moving mechanism 27 is drive-controlled to slidably displace the movable lattice plate 26 in the X′-axis direction, as shown in FIG. , A predetermined range (a portion having a transmittance of 50%) including one end (right end) in the X′-axis direction of the light-shielding portion 32 on the fixed grid plate 25 side, and the X′-axis direction of the light-shielding portion 32 on the movable grid plate 26 side and the like. Positioning is performed so that a predetermined range (portion having a transmittance of 50%) including the end portion (left end portion) overlaps in the X′-axis direction.

As a result, in the grating unit 20, the width of the light-transmitting portion in the X′-axis direction is “300 (15×20) μm”, which is a composite grating pattern in which the grating patterns 30 of both grating plates 25 and 26 are superposed. A virtual lattice pattern is formed in which the width of the light-shielding portion in the “axis direction” is “500 (25×20) μm” and the ratio of the light-transmitting portion to the light-shielding portion is “3:5”.

However, in the light shielding portion of the synthetic lattice pattern, the “300 (15×20) μm” range in the central portion in the X′-axis direction is a high light shielding portion having a transmittance of 25%, and the light shielding portion on both sides of the high light shielding portion in the X′-axis direction. The range of “100 (5×20) μm” is the middle light-shielding portion with a transmittance of 50%.

Then, the first stripe pattern W1 having the first period of 800 μm is generated by the synthetic lattice pattern.

On the other hand, when the second striped pattern W2 having a short cycle is generated, the lattice plate moving mechanism 27 is drive-controlled to slidably displace the movable lattice plate 26 in the X′-axis direction, as shown in FIG. The light shielding portion 32 on the movable lattice plate 26 side is aligned with the central portion of the light transmitting portion 31 on the fixed lattice plate 25 side in the X′-axis direction.

As a result, in the grating unit 20, the width of the light transmitting portion in the X′-axis direction is “100 (5×20) μm”, and X is a composite grating pattern in which the grating patterns 30 of both grating plates 25 and 26 are superposed. A virtual lattice pattern is formed in which the width of the light-shielding portion in the “axis direction” is “300 (15×20) μm” and the ratio of the light-transmitting portion to the light-shielding portion is “1:3”.

However, in the light shielding part of the synthetic grating pattern, the “100 (5×20) μm” range in the central part in the X′-axis direction is a high light-shielding part with a transmittance of 25%, and the high light-shielding part on both sides in the X′-axis direction. The range of “100 (5×20) μm” is the middle light-shielding portion with a transmittance of 50%.

Then, the second grid pattern W2 having the second cycle of 400 μm is generated by the combined grid pattern.

As described in detail above, according to this embodiment, the same operational effects as those of the above-described first embodiment are exhibited. In particular, according to the present embodiment, since the light shielding portion 32 is composed of a plurality of portions having different transmittances, it is possible to project a more ideal stripe pattern W on the printed board 1.

[Sixth Embodiment]
Next, a sixth embodiment will be described in detail with reference to FIG. In the fixed grid plate 25 and the movable grid plate 26 according to the present embodiment, the width of the light transmitting portion 31 in the X′-axis direction is “500 (25×20) μm” and the width of the light shielding portion 32 in the X′-axis direction is “ It is set to "300 (15×20) μm", and the ratio of the light transmitting portion 31 and the light shielding portion 32 is "5:3" [see FIGS. 14(a) and 14(b)].

However, the light shielding portion 32 in the present embodiment is composed of a plurality of portions having different transmittances. More specifically, a medium-transmittance portion is provided between the high-transmittance portion (the light-transmitting portion 31) and the low-transmittance portion (the light-shielding portion 32 having the lower transmittance). ing.

Specifically, an intermediate light-shielding portion having a transmittance of 50% is provided in the “200 (10×20) μm” range in the central portion of the light-shielding portion 32 in the X′-axis direction, and the intermediate light-shielding portion on both sides in the X′-axis direction of the intermediate light-shielding portion is provided. Low light-shielding portions each having a transmittance of 75% are provided in the “50 (2.5×20) μm” range. On the other hand, the transmissivity of the translucent portion 31 in this embodiment is 100%.

When the first striped pattern W1 having a long period is generated, the lattice plate moving mechanism 27 is drive-controlled to slide the movable lattice plate 26 in the X′-axis direction, and as shown in FIG. , A predetermined range (100 μm range) including one end (right end) in the X′-axis direction of the light shield portion 32 on the fixed grid plate 25 side, and the other end (left end) in the X′ axis direction of the light shield portion 32 on the movable grid plate 26 side. (A part) and a predetermined range (100 μm range) are aligned so as to overlap in the X′-axis direction.

As a result, in the grating unit 20, the width of the light-transmitting portion in the X′-axis direction is “300 (15×20) μm”, which is a composite grating pattern in which the grating patterns 30 of both grating plates 25 and 26 are superposed. A virtual lattice pattern is formed in which the width of the light-shielding portion in the “axis direction” is “500 (25×20) μm” and the ratio of the light-transmitting portion to the light-shielding portion is “3:5”.

However, the light-shielding portion of the synthetic grating pattern is a high light-shielding portion having a transmittance of 38% in the “100 (5×20) μm” range in the central portion in the X′-axis direction, and the high light-shielding portion on both sides in the X′-axis direction. The “150 (7.5×20) μm” range serves as a medium light-shielding portion with a transmittance of 50%, and the “50 (2.5×20) μm” range outside thereof has a low light-shielding portion with a transmittance of 75%. Has become.

Then, the first stripe pattern W1 having the first period of 800 μm is generated by the synthetic lattice pattern.

On the other hand, when the second striped pattern W2 having a short cycle is generated, the lattice plate moving mechanism 27 is drive-controlled to slidably displace the movable lattice plate 26 in the X′-axis direction, as shown in FIG. The light shielding portion 32 on the movable lattice plate 26 side is aligned with the central portion of the light transmitting portion 31 on the fixed lattice plate 25 side in the X′-axis direction.

As a result, in the grating unit 20, the width of the light transmitting portion in the X′-axis direction is “100 (5×20) μm”, and X is a composite grating pattern in which the grating patterns 30 of both grating plates 25 and 26 are superposed. A virtual lattice pattern is formed in which the width of the light-shielding portion in the “axis direction” is “300 (15×20) μm” and the ratio of the light-transmitting portion to the light-shielding portion is “1:3”.

However, in the light-shielding portion of the composite lattice pattern, the "200 (10×20) μm" range in the central portion in the X′-axis direction is the middle light-shielding portion with a transmittance of 50%, and the light-shielding portion on both sides of the middle light-shielding portion in the X′-axis direction is located. The range of “50 (2.5×20) μm” is a low light-shielding portion with a transmittance of 75%.

Then, the second grid pattern W2 having the second cycle of 400 μm is generated by the combined grid pattern.

As described in detail above, according to this embodiment, the same operational effects as those of the first and fifth embodiments can be obtained.

It should be noted that the present invention is not limited to the contents described in the above embodiment, and may be implemented as follows, for example. Of course, other application examples and modification examples not illustrated below are naturally possible.

(A) In each of the above embodiments, the projection device and the three-dimensional measuring device according to the present invention are embodied in the board inspection device 10 that inspects the printing state of the cream solder 5 printed on the printed board 1. The invention is not limited to this, and may be embodied in an apparatus for inspecting another target such as an electronic component mounted on a printed circuit board. Of course, it may be configured to perform three-dimensional measurement by using an object different from the printed circuit board as the object to be measured.

(B) In each of the above-described embodiments, the printed circuit board 1 in which the power circuit unit PA and the control circuit unit PB are mixed is used as the object to be measured, and the power circuit unit PA on the printed circuit board 1 has a long first stripe. For example, the pattern W1 is projected to perform three-dimensional measurement, and the second stripe pattern W2 having a short period is projected to the control circuit portion PB to perform three-dimensional measurement. The cycle of the striped pattern W is switched according to the degree of unevenness.

Not limited to this, a printed circuit board having only the power circuit section PA is used as an object to be measured, and only the first striped pattern W1 having a long period is projected on the object to be three-dimensionally measured, and only the control circuit section PB is provided. The measured printed circuit board is used as the object to be measured, and only the second striped pattern W2 having a short period is projected on the measured circuit board to perform three-dimensional measurement. The cycle may be switched.

In addition, a plurality of long-period first striped patterns W1 and short-period second striped patterns W2 may be projected on the power circuit unit PA in plural ways, and the two may be combined to perform three-dimensional measurement. Good. Thereby, although the measurement time is increased, the dynamic range can be expanded without lowering the height resolution.

(C) In each of the above-described embodiments, in performing three-dimensional measurement by the phase shift method, four types of image data in which the phase of the stripe pattern W differs by 90° are acquired. The phase shift amount is not limited to these. Other number of phase shifts and amount of phase shift that can be three-dimensionally measured by the phase shift method may be adopted. For example, three-dimensional measurement may be performed by acquiring three types of image data having different phases by 120° or 90°.

(D) In each of the above-described embodiments, the pattern light having the sinusoidal light intensity distribution is projected as the stripe pattern W when performing three-dimensional measurement by the phase shift method, but the present invention is not limited to this. As the stripe pattern W, for example, a pattern light having a non-sinusoidal light intensity distribution such as a rectangular wave shape or a triangular wave shape may be projected.

However, rather than projecting the pattern light having the non-sinusoidal light intensity distribution and performing the three-dimensional measurement, it is better to project the pattern light having the sinusoidal light intensity distribution and perform the three-dimensional measurement. Therefore, in order to improve the measurement accuracy, it is preferable that the pattern light having a sinusoidal light intensity distribution is projected to perform three-dimensional measurement.

(E) In each of the above-described embodiments, the stripe pattern W is projected on the printed circuit board 1 and the three-dimensional measurement is performed by the phase shift method. However, the present invention is not limited to this. For example, the spatial code method or the moire method is used. Alternatively, the configuration may be such that three-dimensional measurement is performed using another pattern projection method. However, when measuring a small measurement target such as the cream solder 5, it is more preferable to adopt a measurement method with high measurement accuracy such as a phase shift method.

(F) In each of the above-described embodiments, the inspection unit 12 (the projection device 14 and the camera 15) is sequentially moved with respect to a plurality of inspection ranges on the printed circuit board 1 fixed at predetermined positions, so that the entire area of the printed circuit board 1 is covered. It is configured to inspect. The configuration is not limited to this, and the inspection unit 12 may be fixed, and the printed circuit board 1 may be moved to inspect the entire area of the printed circuit board 1.

Further, in each of the above-described embodiments, the projection device 14 is provided with the lattice unit moving mechanism 22 that displaces the lattice unit 20, so that the inspection unit 12 and the printed circuit board 1 are not moved relative to each other, and the print fixed at a predetermined position is performed. Although the relative positional relationship between the substrate 1 and the striped pattern W projected thereon is changed (phase shift), the striped pattern W and the printed circuit board 1 are relatively displaced (pattern light displacement means). Is not limited to the above embodiment.

For example, as described above, when the period of the projected stripe pattern W is not switched over the entire printed circuit board, the printed circuit board is continuously moved by a conveyor or the like, or the inspection unit 12 is continuously moved with respect to the fixed printed circuit board. Thus, the relative positional relationship between the printed circuit board and the stripe pattern W projected on the printed circuit board may be changed (phase shift).

(G) In each of the above embodiments, the light source 19 is composed of a halogen lamp that emits white light. The configuration is not limited to this, and a configuration using another light source such as a white LED may be used.

(H) The configuration of the pattern generation unit is not limited to the lattice unit 20 according to each of the above embodiments.

For example, in each of the above embodiments, the fixed lattice plate 25 and the movable lattice plate 26 are housed in the light-transmitting main body case portion 24. However, the present invention is not limited to this, and the fixed lattice plate may be a frame frame or the like. The plate 25, the movable grid plate 26, and the like may be unitized.

In each of the above-described embodiments, one fixed grid plate 25 is fixed and one or two movable grid plates 26 are provided. However, the present invention is not limited to this, and four or more grid plates face each other. It may be configured to be arranged.

Further, all the lattice plates may be movable lattice plates. For example, the configuration may be such that a first movable lattice plate and a second movable lattice plate are provided, and the relative positional relationship between the two is changed by moving them.

(I) In the lattice unit 20 according to each of the above-described embodiments, the first stripe pattern W1 having a long period is generated corresponding to the power circuit unit PA on the printed circuit board 1, and the short stripe corresponding to the control circuit unit PB is generated. Although the second stripe pattern W2 having a cycle is generated, the number (type) of the stripe patterns W generated by the lattice unit 20 and the specific cycle are not limited to those in the above embodiments. ..

For example, it may be configured such that three or more types of stripe patterns W having different cycles can be generated according to the degree of unevenness of the inspection range on the printed circuit board 1.

(J) The configuration related to the lattice moving means is not limited to the lattice plate moving mechanism 27 according to each of the above embodiments. For example, the grid plate moving mechanism 27 uses the solenoid 27b as a driving means for slidingly displacing the movable grid plate 26, but the invention is not limited to this, and another actuator such as a piezo element may be adopted.

(K) The configuration related to the pattern light displacement means is not limited to the grating unit moving mechanism 22 according to each of the above-described embodiments. For example, the lattice unit moving mechanism 22 uses the piezo element 22b as a driving unit for slidingly displacing the lattice unit 20, but not limited to this, other actuators such as a solenoid may be adopted.

(L) The configurations of the lattice member and the lattice pattern are not limited to the fixed lattice plate 25, the movable lattice plate 26, and the lattice pattern 30 according to each of the above embodiments.

For example, the grid plates 25 and 26 according to the above-described embodiments are configured such that the printing surface of the grid pattern 30 faces the incident side. However, the present invention is not limited to this. It may be arranged so as to face the emitting side.

The fixed grid plate 25 and the movable grid plate 26 may be arranged such that the printing surfaces of the grid pattern 30 face each other, or the non-printing surfaces of the grid pattern 30 face each other. The configuration may be changed. It is preferable to arrange the grid patterns 30 so that the printing surfaces thereof face each other in terms of facilitating focusing of the striped pattern W.

Although not particularly mentioned in each of the above-described embodiments, the fixed lattice plate 25 and the movable lattice plate 26 may be arranged in contact with each other as shown in FIG. 7, or as shown in FIG. The configuration may be such that they are arranged in a state of being separated (close to).

(M) In the lattice plates 25 and 26 according to each of the above-described embodiments, the light-shielding portion 32 is provided on the base material 28 formed in a flat plate shape or a film shape with a predetermined light-transmitting material (eg, glass or acrylic resin). The grid pattern 30 is formed by printing (vapor deposition).

The present invention is not limited to this, and the lattice pattern may be formed by another method such as laser processing.

Alternatively, a grid plate having a grid pattern formed by processing opaque resin, metal, or the like and forming slits or the like may be employed.

Further, the transmissivities of the light transmitting portion 31 and the light shielding portion 32 are not limited to those in the above embodiments. For example, the transmissivity of the light transmitting portion 31 is not limited to 100%, and may be about 95%.

In each of the above embodiments, the fixed grid plate 25 and the movable grid plate 26 have the same grid pattern 30. Not limited to this, as long as a plurality of stripe patterns W having different periods can be generated by these lattice plates 25 and 26, the lattice patterns 30 formed on these lattice plates 25 and 26 may not be the same.

Further, the specific size of the grid pattern 30 such as the width of the light transmitting portion 31 and the light shielding portion 32 is not limited to the above-described embodiments.

(N) The configuration related to the projection optical system is not limited to the projection lens unit 21 according to each of the above embodiments.

For example, the projection lens unit 21 according to each of the above-described embodiments has an entrance side lens 35 and an exit side lens 36, and these lenses 35 and 36 are configured as a both-side telecentric optical system (both-side telecentric lens). Not limited to this, an object side telecentric lens (object side telecentric optical system) may be adopted as the projection lens unit 21. In addition, the configuration may not have a telecentric structure.

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

Further, the imaging lens unit 15b is composed of a both-side telecentric lens (both-side telecentric optical system). Not limited to this, an object side telecentric lens (object side telecentric optical system) may be adopted as the imaging lens unit 15b. In addition, the configuration may not have a telecentric structure.

(P) In the projection device 14 according to each of the above embodiments, the emission surface 20b of the grating unit 20 and the main surface of the projection lens unit 21 are set so as to satisfy the Scheimpflug condition with respect to the printed circuit board 1.

Not limited to this, the Scheimpflug condition may not necessarily be set depending on the focused state of the stripe pattern W in the entire projection range.

Further, it is preferable that the Scheimpflug condition takes into consideration the arrangement and the like of the lattice plates 25 and 26.

Since the synthetic lattice pattern formed on the emission surface 20b of the lattice unit 20 is a lattice pattern in which the lattice patterns 30 of the lattice plates 25 and 26 are superposed, the arrangement configuration of the lattice plates 25 and 26 is not considered, When the exit surface 20b of the grating unit 20 and the main surface of the projection lens unit 21 are arranged so as to satisfy the Scheimpflug condition, a slight error may occur.

DESCRIPTION OF SYMBOLS 1... Printed circuit board, 5... Cream solder, 10... Substrate inspection device, 12... Inspection unit, 13... Control device, 14... Projector, 15... Camera, 19... Light source, 20... Lattice unit, 21... Projection lens unit, 22... Lattice unit moving mechanism, 25... Fixed lattice plate, 26... Movable lattice plate, 27... Lattice plate moving mechanism, 30... Lattice pattern, 31... Translucent part, 32... Shading part, J1... Optical axis of projection device, J3... Optical axis of grating unit, PA... Power circuit section, PB... Control circuit section, W(W1, W2)... Stripe pattern.

Claims (9)

In performing three-dimensional measurement of a predetermined object to be measured, a projection device for projecting a predetermined pattern light onto the object to be measured,
A light source that emits predetermined light,
A pattern generation unit that converts the light incident from the light source into pattern light and emits the light.
A projection optical system for forming an image of the pattern light emitted from the pattern generation unit on the object to be measured,
The pattern generation unit,
A plurality of lattice members having a lattice pattern in which a light-transmitting portion that transmits light with a predetermined transmittance and a light-shielding portion that blocks at least a part of light are alternately arranged in the first direction are orthogonal to the first direction. While being arranged to face each other in the second direction,
By providing a grid moving means capable of changing the relative positional relationship of the plurality of grid members with respect to the first direction,
A projecting device, characterized in that the cycle of the pattern light projected onto the object to be measured can be changed. The projection device according to claim 1, wherein the plurality of lattice members have the same lattice pattern. The pattern generation unit,
A light-shielding portion of the lattice pattern in one of the two lattice members facing each other in the second direction and a light-shielding portion of the lattice pattern in the other lattice member are continuous in the first direction. By arranging the two grating members, it is possible to generate long-period pattern light,
By arranging the two lattice members such that the light shielding portion of the lattice pattern of the one lattice member and the light shielding portion of the lattice pattern of the other lattice member are separated in the first direction, The projection device according to claim 1 or 2, wherein the projection device is configured to be capable of generating periodic pattern light. The pattern generation unit,
An end position on one end side in the first direction of the light shielding portion of the grid pattern in the one grid member and an end position on the other end side in the first direction of the light shielding portion of the grid pattern in the other grid member are first. The projection device according to claim 3, wherein the two grating members are arranged so as to be in the same position in the direction, and the long-period pattern light can be generated. The pattern generation unit,
The predetermined range including one end in the first direction of the light shielding portion of the lattice pattern in the one grid member, and the predetermined range including the other end in the first direction of the light shielding portion of the grid pattern in the other lattice member are The projection device according to claim 3, wherein the two grating members are arranged so as to be overlapped in the first direction so that the long-period pattern light can be generated. 6. The plurality of lattice members are constituted by one fixed lattice member and at least one movable lattice member provided so as to be relatively displaceable with respect to the fixed lattice member. The projection device according to any one of claims. The projection device according to any one of claims 1 to 6, wherein the light-shielding portion includes a plurality of portions having different transmittances. 8. The projection device according to claim 1, wherein pattern light having a striped light intensity distribution can be projected as the pattern light. A projection device according to claim 1,
An image capturing unit capable of capturing an image of a predetermined range of the measured object onto which the pattern light is projected;
A three-dimensional measuring device comprising: an image processing unit capable of performing three-dimensional measurement of the object to be measured based on the image data captured and acquired by the image capturing unit.

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