JP3446741B2 - Light beam deflection control method and optical shaping apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light beam deflection control method and a stereolithography apparatus. Specifically, for example, a method of controlling the deflection of the light beam used in a stereolithography method for forming a three-dimensional shape by stacking a plurality of solidified layers formed by irradiating and solidifying a solid material with a light beam, and the light The present invention relates to a stereolithography apparatus using a beam deflection control method.

[0002]

2. Description of the Related Art An inorganic powder (metal) or an organic powder (resin) is irradiated with a light beam (directional energy beam, laser) to be cured, and a cured layer is laminated to manufacture a three-dimensional shaped object. The method is, for example, Japanese Patent No. 2620353.
It is shown in the publication.

Usually, the design of parts manufactured by the above method is performed by three-dimensional CAD. The laser path of each layer is determined based on the cross-sectional shape data of each layer generated by slicing the designed three-dimensional CAD model to a desired layer thickness, and the powder for one layer is sintered (cured). At the same time, it is also sintered (bonded) to the immediately preceding layer,
It is a method of manufacturing component shapes by continuously stacking.

On the other hand, a surface finishing method for a modeled object manufactured by the method is disclosed in Japanese Patent Laid-Open No. 2000-73108. According to this method, the stepped portion where the edge of each sintered layer forming the surface of the metal powder sintered component is protruding is finished by laser irradiation or the like after or during the production of the metal powder sintered component.

However, since the irradiated laser beam (light beam) usually uses an optical scanner, the search of the processed surface is distorted, and the search is performed in order to search the laser beam along the path obtained by the three-dimensional CAD. The route needs to be corrected.

[0006] As this correction method, when a measuring device for calculating the correction amount is not provided, a basic pattern is drawn, an off-line deviation amount is measured, and a correction term by manual input is added and drawn again. The above-mentioned work is repeated until the laser beam can be irradiated to a desired position. However, with this method, it is necessary to repeat the drawing of the basic pattern, the measurement of the shift amount, and the correction by manual input, and this correction requires a great deal of time and labor.

Further, a conventional technique having a measuring device for calculating a correction amount is disclosed in, for example, Japanese Patent No. 2979431. The method comprises the steps of generating a test pattern by exposing a photosensitive medium to a laser beam at a predetermined desired position as a function of position coordinates, and producing a digitized partial image of the portion of the test pattern. The step of assembling the digitized partial image into the entire test pattern image, the step of comparing the actual position of the laser beam on the entire image with the position coordinates, and the laser based on the comparison. And a step for calculating and providing correction data for the beam deflection controller.

In this method, the area for obtaining the partial image may be at any position of the test pattern, and even the positional relationship between the reference position information (center code: point R in FIG. 24) and the area is grasped. If you have. Further, it is possible to cope even if the area for obtaining the partial image does not include the position information indicating the coordinates. Therefore, even if the deviation of the test pattern is large, it can be dealt with.

[0009]

However, in the above-mentioned conventional technique, the correction amount cannot be calculated unless the positional relationship between the area where the partial image is obtained and the center code is known. That is, in order to process one screen of the entire image, two pieces of information, that is, the positional information of the area where the partial image is obtained and the positional information of the center code are required.

Further, as shown in FIG. 24, it is general that a camera moving coordinate system for imaging and a laser irradiation coordinate system for correction are formed as different coordinate systems. There is a problem that it takes much time to assemble the whole image. Further, there is a possibility that the camera visual field coordinate axes may be displaced due to the mounting offset with respect to the camera mounting base, and in this case as well, there is a problem that it takes much time and effort to assemble the entire image.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to correct the search path of the light beam by a simple method.

[0012]

A light beam deflection control method according to the present invention is a light beam deflection control method for irradiating an object to perform shaping or processing, and is arranged on a predetermined plane. Capturing a reference pattern with a camera to acquire a partial image of the reference pattern and an imaging position of the camera; and emitting a light beam to the position of the reference image data obtained by acquiring the partial image of the reference pattern. Illuminating and drawing an irradiation pattern on the top surface of the marking object aligned on the plane, and photographing with a camera corresponding to the imaging position.
Acquires partial <br/> image of radiation patterns the drawing by the image to obtain a radiation image data, thus obtained
Reference image data with partial images corresponding to the same imaging position
Image data comparison step of comparing the irradiation data with the image data, and a correction data calculation step of calculating deflection correction data of the light beam based on the comparison result obtained by the image data comparison .

[0013]

At this time, it is preferable that the center of the partial image coincides with the center of image pickup by the camera.

Further, in each of the above inventions, it is desirable that the plane on which the reference pattern is arranged coincides with the processing plane of the object.

In these inventions, it is preferable to use grid points arranged in a grid pattern at a predetermined equal pitch as the reference pattern. When acquiring a partial image,
It is preferable that the partial image to be acquired include one grid point arranged in a grid pattern at a predetermined equal pitch.

As the reference pattern, it is possible to use, for example, a plate-shaped body or a film-shaped body stamped or printed.

As the material to be marked, a material such as a resin plate whose surface layer can be engraved by irradiation with a light beam can be used, and can be peeled off by the light beam irradiated on the upper surface of the base material layer. It is desirable to have a surface layer that is different from the color of the certain substrate layer. Alternatively, a heat sensitive body whose surface color is changed by irradiation with a light beam can be used.

Further, in the present invention, it is convenient that the irradiation pattern and the reference pattern are the same pattern.

Further, in the present invention, based on the image data, an image density change point is searched along the outer circumference of the obtained image area, and then the image is drawn along a line inside a certain distance from the outer circumference. It is possible to find grid point coordinates in the image data by repeating the search for the gradation change points.

Alternatively, based on the image data, after searching for an image density change point along the outer periphery of the obtained image area, a region defined by the coordinates obtained from the image density change point on the outer periphery is searched. It is also possible to find grid point coordinates in the image data by repeating the search on the boundary line.

Further, after searching for an image density change point along the outer periphery of the obtained image area on the basis of the image data, it is then located on the opposite side 2 obtained from the image density change point on the outer periphery. The grid point coordinates in the image data can also be obtained by repeatedly calculating the intersection of line segments formed from the set of coordinates and searching the outer peripheral line of the area at a constant distance with the intersection as the center.

Further, based on the image data, after searching for an image density change point along the outer periphery of the obtained image area, an image density change point is searched for along a line which is inside a certain distance from the outer periphery. However, the grid point coordinates may be obtained from the simultaneous equations obtained from the vertical line segment and the horizontal line segment obtained from these change points.

At this time, with respect to the two image grayscale change points corresponding to the line segment width, the grid point coordinates are obtained using the midpoint coordinates of the two points, or the image area is calculated based on the image data. It is possible to search for image grayscale change points along the outer peripheral portion or the inner circumference that is separated from the image grayscale change points by a plurality of lines at constant small distance intervals and use them as coordinate values of the image grayscale change points.

Further, in the present invention, it is preferable to change the deflection correction data in correspondence with the image acquisition position of the irradiation pattern or the reference pattern.

The stereolithography apparatus according to the present invention is a stereolithography apparatus for stacking a plurality of solidified layers formed by irradiating and solidifying a material to be solidified with a light beam to form a desired three-dimensional shape on a predetermined plane. portions of placed reference pattern image and,
The reference of the upper surface of the object to be marked arranged on the plane
Reference image data obtained by acquiring the partial image of the pattern
Of the irradiation pattern drawn by irradiating the position of
Partial images, acquired at the same imaging position, the reference image data
And obtained Ru image acquiring means and the data and the irradiation image data, the image
Partial image corresponding to the same imaging position obtained by the acquisition means
Compare the reference image data with the image and the irradiation image data,
A correction data calculation unit that calculates the deflection correction data of the light beam based on the comparison result, and a deflection control unit that controls the deflection of the light beam based on the deflection correction data obtained by the correction data calculation unit. It is characterized by having.

[0027]

1 and 2 are schematic configuration diagrams of a stereolithography apparatus according to an embodiment of the present invention. The optical modeling apparatus is a tank-shaped supply unit 20 in which a powder material used for modeling is stored, and a molded product is manufactured adjacent to the supply unit 20.
It is provided with a modeling unit 10 having a tank shape similar to the supply unit 20. The modeling unit 10 and the supply unit 20 have the same planar shape.

A modeling table 11 which constitutes the bottom surface of the modeling section 10.
Can be moved up and down by a table drive mechanism.
A hardened layer formed by photo-curing a powder material is sequentially stacked on the modeling table 11 to fabricate a modeled object. Further, the bottom surface 21 of the supply unit 20 can also be lifted and lowered by the table lifting mechanism. The table drive mechanism is supported by, for example, a ball screw 12 that is rotationally driven by a servo motor 13, a linear guide rail that guides the up-and-down movement of a slide body of the ball screw 12, and a slide body of the ball screw 12 that serves as a modeling table 11. And a cylinder surrounding the table (modeling table 11). The table drive mechanism can drive the modeling table 11 and the bottom surface 21 independently of each other.

The transfer blade 30 is in the form of a plate having a narrow width longer than the inner widths of the modeling section 10 and the supply section 20, and both ends of a support plate 31 provided on the upper part thereof are supported by the reciprocating device 32. There is. The transfer blade 30 passes over the supply unit 20 and the modeling unit 10 from the outside of the supply unit 20 and passes through the modeling unit 1.
Move horizontally to the outside of 0.

A light beam irradiation device 40 for irradiating a light beam L such as a laser beam is arranged above the modeling section 10. The light beam irradiation device 40 includes an irradiator 4 for the light beam L.
The light beam L emitted from 2 is deflected or focused by an optical system in which a plurality of movable mirrors 47 and lenses are combined to irradiate the powder material in the modeling unit 10. The focus of the light beam L is adjusted by an optical scanner (for Z axis) 46 such as a galvano scanner, and Z
The irradiation position in the axial direction is adjusted, and the irradiation position in the plane of the modeling unit 10 is adjusted by the optical scanner (for XY axes) 43. Further, the laser diameter of the light beam L is adjusted by the condensing diameter variable table 45. The focus control, the irradiation position, and the laser diameter adjustment are controlled by the deflection control device 41 in response to a search command (scan command) from the control computer 48.

Above the modeling unit 10, a correction photographing device, for example, a camera 51 having a zoom mechanism such as a CCD camera or a line sensor used in a copying machine is arranged. The camera 51 is slidably attached to a moving table 52 arranged above the modeling unit 10. Further, the moving table 52 is supported by guide driving portions 53 arranged along both outer sides of the modeling unit 10 and the supply unit 20, and slides along the guide driving units 53. As a result, the camera 51 can freely move in the XY directions above the modeling unit 10. The guide driving unit 53 is controlled by the control computer 48, and the position of the camera 51 is grasped by the control computer 48. Camera 51
Is connected to an image processing device 50 including a computer having a storage device, and an image captured by the camera 51 is sent to the image processing device 50. In the image processing device 50, the irradiation position of the light beam L is determined from various image data captured as described below, and the control computer 48 issues a corrected search command.

Further, as shown in FIG. 2, a powder supplying / discharging device is arranged above the modeling unit 10 and the supplying unit 20.
In the powder supplying / discharging device, the powder removing nozzle 60 arranged above the modeling unit 10 passes through a flexible hose 62,
It is connected to the powder separating device 61 and the suction pump 65. When the suction pump 65 is operated, the powder removing nozzle 6
Inhale powder with air from the tip of 0. The powder separating device 61 separates air from powder, and the powder is stored and stored in an auxiliary tank (not shown) provided in the powder separating device 61 or returned from the lower end of the powder separating device 61 to the supply section 20. . The air from which the powder has been separated is discharged from the suction pump 65 to the outside.

The powder removing nozzle 60 is slidably attached to the support bar 63. The support bar 63 is supported by a guide drive unit 64 arranged along both outer sides of the modeling unit 10 and the supply unit 20, and slides along the guide drive unit 64. As a result, the powder removing nozzle 60 is
Move freely in both XY directions above. Although the camera 51, the image processing device 50, and the like and the powder separating device 61 are illustrated in different drawings, they are installed in one optical modeling device and are a guide drive for driving the camera 51. Part 5
The guide drive unit 64 for driving the support bar 63 and the guide bar 3 can be used both as long as the camera 51 and the support bar 63 can be driven independently. Further, most of the stereolithography apparatus is housed in a processing chamber (not shown) that forms a closed space. However, most of the light beam irradiation device 40, the control computer 48, and the image processing device 50 are installed outside the processing chamber, and the light beam L is irradiated to the inside of the processing chamber through, for example, a lens provided on the wall surface of the processing chamber. To be done. Pipes and valves are connected to the wall surface of the processing chamber through the air supply / exhaust ports, and it becomes possible to send pressurized air into the processing chamber, suction the exhaust gas, and create a desired gas atmosphere. There is.

In this modeling apparatus, the deflection control of the light beam L can be corrected. The correction is
A step of acquiring an image of the reference pattern arranged on the modeling table 11, and an irradiation pattern on the upper surface of the marking object 80 aligned with the modeling table 11 by irradiating the position of the obtained reference image data with the light beam L. Drawing step, an image data comparison step of comparing the irradiation image data obtained by acquiring the image of the irradiation pattern with the reference image data, and deflection correction data of the laser beam based on the comparison result. And a correction data calculating step for calculating.

Next, the correction procedure will be described step by step. First, the reference plate 70 on which the position for camera measurement is marked is placed on the modeling table 11, and the camera 51
The image of the reference pattern drawn on the reference plate 70 is acquired at.

The reference plate 70 is made of a plate material or a film material having a flat surface such as a glass plate, an acrylic plate or a plastic sheet, and a reference pattern is drawn on the upper surface by engraving or printing.
This reference pattern serves as a reference for matching with the search line of the actual light beam L, and for example, as shown in FIGS. 3 and 4, grid points 71 arranged in a grid pattern at a predetermined equal pitch. Is used. In the reference plate 70 shown in FIG. 3, vertical and horizontal lines extending over substantially the entire width of the reference plate 70 are drawn at equal pitches to draw a grid pattern, and in the example of the figure, it is composed of 9 × 9 = 81 grid points 71. A reference pattern is provided. Further, in the reference plate 70 shown in FIG. 4, grid points 71 are drawn from short vertical lines and horizontal lines,
The grid points 71 are provided in a matrix, and in the example shown in the figure, a reference pattern made up of 9 × 9 = 81 grid points 71 is provided. The interval between the grid points 71 is not particularly limited and is set arbitrarily. The area surrounded by the grid points 71 is a correctable area.

The reference plate 70 is placed on the modeling table 11 as shown in FIG. A positioning mechanism for positioning the reference plate 70 is provided on the modeling table 11. The positioning mechanism may be any one as long as the mounting position of the reference plate 70 can be made constant, and for example, in the example of the figure, it is composed of three positioning pins 14. At this time, the reference plate 70 raises the modeling table 11 by the table drive mechanism as shown in FIG. 6, and the upper surface of the reference plate 70 ((b) in the figure) is machined at the height of the machined surface during actual modeling ( The height is adjusted as shown in FIG. As a result, it becomes possible to correct to the actual processing plane, and the search accuracy of the light beam L is improved.

Next, as shown in FIG. 7A, the camera 51 is moved to a desired position by driving the guide driving section 53 and the like. At this time, as shown in FIG. 7B, the camera 51 is moved so that at least one lattice point 71 is included in a predetermined position within the field of view of the camera 51. The position information of the camera 51 is grasped by the control computer 48. Further, although the entire area of the reference pattern may be included in the visual field of the camera 51, a partial area of the reference pattern is formed by the zoom mechanism of the camera 51, preferably one grid point 71 as shown in FIG. 7B. It is preferable to include only. When a partial area is included, it is preferable that the center of the field of view M (imaging center) of the camera 51 coincides with the center of the partial image, that is, the center of one grid point 71, as shown in FIG. This is because, as shown in FIG. 9A, by making the center of the lattice point 71 coincide with the imaging center of the camera 51, it is possible to deal with the deviation direction of the light beam L evenly. On the other hand, as shown in FIG.
This is because if the position is deviated from the imaging center of 1, the position where the misregistration can be detected (in the circle in the figure) is small, and there is a possibility that correction may not be possible.

In this way, the picked-up image is sent to the image processing device 50 in correspondence with the picked-up position stored in the control computer 48 and stored as reference image data in the storage device. In addition, since the captured image is a partial region of the reference pattern, it is enlarged as compared with the case where the entire region is captured at once, and more accurate correction can be performed.

Next, the light beam L is actually applied to the marking material 8
The deviation amount (correction amount) to be corrected is obtained by irradiating 0.
Prior to the calculation of the correction amount, the irradiation pattern is first drawn on the marking material 80. As the marking material 80, a material on which an irradiation image is formed by irradiation of the light beam L is used. For example, a material such as a resin plate such as an acrylic plate or a glass plate whose surface layer can be engraved by irradiation heat can be used. At this time, as shown in FIGS. 10A and 10B, the size (width or depth) of the groove formed in the marking target material 80 changes depending on the size of the energy of the light beam L and the difference in the spot diameter. Therefore, the light beam L is arranged so that the state of the surface of the marking object 80 after irradiation can be easily observed.
The energy and spot diameter are determined in advance. Preferably, as shown in FIG. 10B, the light beam L is preferably focused, and the inclination angle of the groove becomes steep, which makes it easy to estimate the center line. In this way, by engraving the groove in the material 80 to be marked, it is possible to easily observe the lattice points 71.

Further, as the marking material 80, as shown in FIG. 11, a material having a surface layer 82 which can be peeled off by irradiation of the light beam L on the upper surface of the base material layer 81 can be used. The surface layer 82 is colored differently from the base layer 81. The surface layer 82 is peeled off by the irradiation of the light beam L, and it becomes easy to grasp the irradiation image obtained by the irradiation of the light beam L. Therefore, it is preferable to color the surface layer 82 and the base material layer 81 so that the contrast becomes clear.

FIG. 12 is a perspective view showing another marking material 80. In the marking material 80, the thermal paper 83 is provided on the upper surface of the base material layer 81 whose surface has a sufficient flatness. It is closely attached. A plate-like material such as a glass plate is used for the base material layer 81. Thermal paper 83
Is a light-sensitive paper 83 whose color is changed by the light beam L, which may be adapted to, for example, a general facsimile receiver, and which is a special thermal paper 83 used for industrial purposes and set to high sensitivity. But it's okay. The thermal paper 83 is adhered to the base material layer 81 with an adhesive, but it is preferable to use a removable adhesive. Cheap thermal paper 8
By peeling off 3, the base material layer 81 can be reused, and the running cost for correction can be reduced. When irradiating the light beam L, the output and speed of the laser beam are adjusted according to the sensitivity of the thermal paper 83 used, and a desired irradiation image is obtained.

The irradiation pattern drawn at this time is preferably the same pattern as the previously obtained reference pattern, for example, the size and thickness of the lattice points have the same shape. As a result, the same method can be used as the grid point detection method for the photographed reference pattern and the irradiation pattern. Further, when capturing the irradiation pattern, it is preferable to obtain an image of a part of the illumination image within the field of view of the camera 51 as in the case of capturing the reference pattern, and only one lattice point should be obtained in the partial image. Is desirable. The irradiation image obtained is also controlled by the control computer 48.
Corresponding to the image pickup position stored in, the image is sent to the image processing device 50 and stored as irradiation image data in the storage device.

The reference image data corresponding to the same image pickup position thus obtained is compared with the irradiation image data to calculate the correction amount. As shown in FIG. 13, the specific calculation of the correction amount is performed by calculating the positional deviation between the grid points of the irradiation image data (FIG. 13A) obtained by irradiating the light beam L and the grid points of the reference image data. The number of pixels and the line width of the irradiation image data (see FIG.
(B) Shown in black. ) Is done from.

Next, a method of detecting the number of pixels of positional deviation will be described. The coordinates of the grid points of the captured reference image data and irradiation image data are used to detect the number of pixels of the positional deviation. Therefore, it is necessary to detect the coordinates of each grid point in the image acquisition area. FIG. 14 is an explanatory diagram showing the principle of detecting grid point coordinates. To detect the grid point coordinates, for example, as shown in FIG. 14, the field of view of the camera 51 is sequentially searched in the lateral direction with a predetermined width, and the intersection of the line width indicating the grid point in the image data and the search line is detected. It can be calculated by the number and the number. The line width can be calculated by detecting the shade change points on the image, that is, by the number of images of the points changing from light to dark and the points changing from dark to light. In the example shown in FIG. 14, the search line a at the top has two change points and the line width is relatively thin, and the search line b also has two change points and the line width is relatively thin. In the search line c, there are four transition points, which are a relatively thin line width and a relatively thick line width. Next, in the search line d, there are two change points, but the line width is thick, and the search line e
In, there are again four transition points, a relatively thick line width and a relatively thin line width. From this result, it can be seen that there are grid points on the search line d (coordinate X). Therefore, if the position information on the search line is known, the coordinate P (X, Y) of the grid point can be obtained by detecting the grayscale change point and the line width on the search line.

At this time, when the light beam L is irradiated, the lattice points always have a constant line width h. In this case, for example, as shown in FIG. 15, two grayscale change points p1 (light to dark) and a grayscale change point p2 obtained in the search direction.
The midpoint P (dark to light) can be used as the coordinate value.

The coordinate value p may be obtained by searching once in one direction, but the line width of the grid points is not always constant as shown in FIG. The boundary line with the point) has irregularities. Therefore, at the time of searching, three gray-scale change points p1, p2, and p3 are detected by a plurality of search lines with the width of a fixed minute interval Δd, three search lines in the example of the figure, and the average of the three gray-scale change points is detected. It is preferable to use coordinates as coordinates. As a result, the measurement error can be reduced, and the method is particularly effective when the boundary line is not clear and when the unevenness of the boundary line is large.

Next, a method for searching the coordinates P of the actual grid point will be described. FIG. 17 is an explanatory diagram showing an example of the method. In this method, unlike the above method, the search is sequentially moved from the outer circumference to the inner circumference of the imaging range to determine the coordinates P of the grid points. First, the outer periphery (search line a) of the acquired image is searched for, and the Y coordinate of the point A, the X coordinate of the point B, the Y coordinate of the point C, the X coordinate of the point D where there are two grayscale change points are searched. To detect. Next, a search is again performed on the first inner circumference (search line b) that is inside the fixed distance d from this outer circumference, and the Y coordinate of the E point and the X coordinate of the F point where there are two gradation change points, The Y coordinate of the G point and the X coordinate of the H point are detected. Further, the search is again performed on the second inner circumference (search line c) which is inside the predetermined distance d ′ from this inner circumference. By repeating this procedure, a search is performed up to the point where the number of shade change points changes and the width becomes wider. In this case, the coordinate P (X, Y) of the grid point is detected by detecting the X coordinate or the Y coordinate on the search line while changing the search position from the outer circumference to the inner circumference by a constant distance d, d '. Is required.

FIG. 18 is an explanatory view showing another method for searching the coordinates P of the lattice points. In this method, first, the outer periphery of the imaging range (search line a) is searched for, and the Y coordinate of the A point, the X coordinate of the B point, the Y coordinate of the C point, and the D point where there are two grayscale change points. The X coordinate of is detected. Next, point A, point B, C
A search is made on the boundary line (search line b) surrounded by the points D and D. By gradually limiting the search range in this manner, the search is performed up to the point where the number of grayscale change points changes and the width becomes wider. By adopting such a method, the search range becomes narrower than that of the above method, so that the time for obtaining the coordinate P of the grid point can be shortened.

FIG. 19 is an explanatory diagram showing another method for searching the coordinates P of the lattice points. In the method,
Searching on the outer periphery (search line a) of the imaging range, the Y coordinate of the point A, the X coordinate of the point B, and the Y coordinate of the point C, where there are two grayscale change points, are searched.
After detecting the coordinates and the X coordinate of the D point, a line segment formed from two sets of coordinates on opposite sides, that is, a line segment connecting the A point and the C point and a line segment connecting the B point and the D point. The intersection point P'of is detected. Next, a search is made on the boundary line (search line b) surrounded by the line segment that is separated from the intersection P ′ by a certain distance d,
The Y coordinate of the E point, the X coordinate of the F point, the Y coordinate of the G point, and the X coordinate of the H point, which have two grayscale change points, are detected. And
Again, a line segment formed by two sets of coordinates on opposite sides, that is, an intersection point P ″ (not shown) of a line segment connecting the E point and the G point and a line segment connecting the F point and the H point is defined. To detect. In addition, a search is performed on the boundary line of the range surrounded by the line segment that is apart from the intersection P ″ by the constant distance d ′. In this way, the search range is limited and the coordinates P of the grid point are searched. At this time, it is preferable to reduce the distance for narrowing the search range as moving to the inside of the imaging range (distance d '<distance d). By adopting this method, the coordinate P of the grid point can be detected with a smaller number of searches unless an extreme shift occurs.

In the method shown in FIG. 20, the outer circumference (search line a) of the image pickup range is searched for, and the Y coordinate of the point A, the X coordinate of the point B, and the Y coordinate of the point C where there are two gradation change points. After detecting the coordinates and the X coordinate of the point D, a search is performed on the inner circumference (search line b) that is inside by a certain distance d from the outer circumference (search line a), and 2
Y coordinate of E point, X coordinate of F point,
The Y coordinate of the G point and the X coordinate of the H point are detected. Next, two equations obtained respectively from a vertical line segment and a horizontal line segment obtained from these change points, for example, a line segment connecting points A and E and a line segment connecting point B and F. By obtaining the solution (intersection point) of, the coordinate P of the lattice point can be approximately obtained. In such a method, since the procedure can be simplified, the coordinate P of the lattice point that is approximate but desired can be easily obtained. Further, as the line segment for obtaining the equation, a solution of a line segment other than the above, for example, a line segment connecting the C point and the G point and a line segment connecting the D point and the H point may be obtained.

With such a method, as shown in FIG. 21, the coordinates (X0, Y0) of the grid points of the standard image data and the grid point coordinates (X, Y) of the irradiation image data are calculated to obtain the correction amount. . This correction amount is obtained by the following procedure, for example. The shift pixel amount is calculated from both coordinates. δX = X−X0, δY = Y−Y0 The pixel amount is converted to the actual shift amount (mm). ΔX = K · δX, ΔY = K · δY: Here, K is a correction coefficient from the pixel amount. Calculate the correction angle. Δθx = Cp, q · ΔX, Δθy = Cp, q · ΔY: where Cp,
q is a correction coefficient for the shift amount at the partial image acquisition position. A correction amount for the deflection control unit is calculated. θ'x = θx + Δθx, θ'y = θy + Δθy

In the calculation of the correction amount, the correction amount is also used to correct the deviation amount. For this correction angle, different correction coefficients determined for each coordinate of each grid point are used. In the example shown in FIG. 22, as the irradiation pattern, nine grid points in the p-axis direction and nine grid points in the q-axis direction, a total of 81 grid points, are drawn, and the correction coefficient Cp is set for each grid point. , q, that is, C1,1, C1,2, ... C9,
A total of 81 correction coefficients up to 8, C9, 9 are set for each grid point. This correction coefficient Cp, q is actually the light beam L
Is obtained by irradiating.

In the above method, it is conceivable to use a single correction coefficient at all grid points. However, as shown in FIG. 23B, even if the movable mirror 47 reflects the light beam L so that the beam spread angles θ1 and θ2 are equal, as shown in FIG. The area T2 in the vicinity has a small spread of the irradiation surface, and the area T1 far from the movable mirror 47 has a large spread of the irradiation surface. Therefore, if the same correction coefficient Cp, q is used, an error will occur. Therefore, the correction coefficient Cp, q is increased in the region T2 immediately below the movable mirror 47 where the influence of the angle of the movable mirror 47 is small, and the correction coefficient Cp, q is increased in the region T1 away from the reflector where the angle of the movable mirror 47 is greatly affected. Make it smaller. The correction coefficient Cp, q is made to correspond to the imaging position of the grid point (reference pattern or irradiation pattern) thus imaged.
The correction data can be obtained more accurately by changing the.

By correcting the deflection control amount of the light beam L in this manner, laser processing can be performed in conformity with a desired processing pattern. In particular, in the present invention, since the correction amount is obtained by actually irradiating the light beam L after imaging the reference pattern, position information is included in each image that has been imaged, and the camera movement axis for imaging is Even if the irradiation coordinate axis of the light beam L is deviated, the correction amount can be accurately obtained without being affected by the deviation. Moreover, since the correction amount can be obtained from the partial image of the reference pattern, the correct correction amount can be obtained with a small number of steps.

[0056]

According to the present invention, the work of calibrating the scanning path of the light beam can be automatically performed. In particular, the reference pattern arranged on the predetermined plane is imaged in advance,
After that, since the position is aligned with the reference pattern and the irradiation pattern obtained by actually irradiating the light beam is compared, the correction amount can be obtained only from the captured image. Therefore, the correction amount can be obtained very easily, and the improvement in modeling accuracy can be expected. In particular, even if the camera movement axis and the irradiation coordinate axis of the light beam are deviated, an accurate correction amount can be obtained without any problem.

By photographing the reference pattern with the camera, a part of it can be enlarged and photographed, and the accuracy thereof can be improved.

Therefore, according to the optical modeling apparatus using the method for controlling the deflection of the light beam according to the present invention, the surface shape of the three-dimensional model can be finished very easily and accurately.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a stereolithography apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a stereolithography apparatus according to an embodiment of the present invention.

FIG. 3 is a diagram showing an example of a reference pattern used in the light beam deflection control method of the present invention.

FIG. 4 is a diagram showing another example of the reference pattern in the above.

5A and 5B are explanatory diagrams showing a method of installing a reference plate in the laser beam deflection control method, wherein FIG. 5A is a side explanatory view thereof and FIG. 5B is a plan explanatory view thereof.

6A and 6B are explanatory views showing the height adjustment of the modeling table in the above, wherein FIG. 6A is the modeling table height at the time of modeling, and FIG. 6B is the modeling table height at the time of correcting the light beam. FIG.

FIG. 7 is an explanatory diagram showing a reference pattern imaging method,
The figure (a) is the side explanatory drawing, and the same figure (b) is the plane explanatory drawing.

FIG. 8 is a diagram showing a method of adjusting an image pickup center.

9A and 9B are explanatory diagrams showing problems with respect to the center of imaging, FIG. 9A is a diagram showing a preferable state, and FIG. 9B is a diagram showing a bad state.

10A and 10B are explanatory diagrams showing a method of irradiating a marking target with a laser beam, wherein FIG. 10A shows a case where the beam diameter is large, and FIG. 10B shows a case where the beam diameter is small.

FIG. 11 is a side view showing an object to be marked in the above laser beam deflection control method.

FIG. 12 is a perspective view showing another example of an object to be marked.

13A and 13B are schematic explanatory views showing a correction method of the present invention, wherein FIG. 13A shows the obtained irradiation pattern, and FIG. 13B shows correction based on the reference image data and the irradiation image data. It is a figure which calculates | requires quantity.

FIG. 14 is an explanatory diagram showing a principle of detecting grid point coordinates.

FIG. 15 is an explanatory diagram showing a method of detecting coordinate values.

FIG. 16 is an explanatory diagram showing another method of detecting coordinate values.

FIG. 17 is an explanatory diagram showing an example of a search method of grid point coordinates in the laser beam deflection control method of the above.

FIG. 18 is an explanatory diagram showing another example of a method for searching lattice point coordinates in the above laser beam deflection control method.

FIG. 19 is an explanatory diagram showing still another example of a method for searching for lattice point coordinates in the above laser beam deflection control method.

FIG. 20 is an explanatory diagram showing still another example of the search method of the lattice point coordinates in the above laser beam deflection control method.

FIG. 21 is an explanatory diagram for obtaining a correction amount in the laser beam deflection control method of the above.

FIG. 22 is a diagram showing a relationship between grid points and correction coefficients.

FIG. 23 is an explanatory diagram showing the necessity of a correction coefficient, and FIG. 23A is an explanatory diagram showing the relationship between the imaging range and the correction coefficient;
FIG. 11B is an explanatory diagram showing the relationship between the correction coefficient and the movable mirror.

FIG. 24 is an explanatory diagram showing a problem in a conventional laser beam deflection control method.

[Explanation of symbols]

10 modeling department 11 modeling table 14 Positioning pin 20 Supply Department 30 Transfer blade 32 reciprocating device 40 Light beam irradiation device 41 Deflection control device 42 Irradiator 43 Optical scanner (for XY axes) 45 Focusing diameter variable table 46 Optical Scanner (for Z axis) 47 movable mirror 48 control computer 50 image processing device 51 camera 52 Moving table 53 Guide drive unit 3 60 powder removal nozzle 61 Powder Separator 62 hose 63 Support bar 64 Guide drive 70 Reference plate 71 grid points 80 Marking material 81 Base material layer 82 surface layer 83 Thermal paper

Front page continuation (72) Inventor Tokuo Yoshida 1048 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works, Ltd. (56) Reference JP 2000-326416 (JP, A) JP 2002-103459 (JP, A) Special Kaihei 8-318574 (JP, A) Patent 2979431 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02B 26/10 B22F 3/105 B23K 26/00-26/18 B29C 67/00

Claims (19)

(57) [Claims] 1. A deflection control method of a light beam for irradiating an object to perform modeling or processing , comprising capturing a reference pattern arranged on a predetermined plane with a camera.
Acquiring a partial image of the reference pattern and the image pickup position of the camera by irradiating a light beam to the position of the reference image data obtained by acquiring the partial image of the reference pattern and aligning the object on the plane. By drawing an irradiation pattern on the upper surface of the marking body, and by imaging with a camera corresponding to the imaging position
Irradiation to obtain a partial image of the rendered irradiation pattern
Image data is obtained and paired to the same imaging position obtained in this way.
An image data comparison step of comparing the reference image data and the irradiation image data based on the corresponding partial image; and a correction data calculation step of calculating deflection correction data of the light beam based on the comparison result obtained by the image data comparison. A method for controlling the deflection of a light beam, comprising: Wherein the center of said partial image, the deflection control method of an optical beam according to claim 1, characterized in that to match the imaging center of the camera. Wherein the plane to place the reference pattern, the light beam deflection control method according to claim 1 or 2, characterized in that fitted to the machining plane of the object. Wherein said reference pattern, a light beam deflection control method according to claim 1, 2 or 3, characterized in that a grid points arranged in a grid pattern at a predetermined equal pitch. To wherein said partial image, according to claim 1, characterized in that the grid points arranged in a grid pattern at a predetermined equal pitch are included one light beam according to any of the 2, 3 or 4 Deflection control method. Wherein said reference pattern, the deflection control of the light beam according to any one of claims 1, 2, 3, 4 or 5, characterized in that stamped or printed on the plate-like body or a film-like body Method. Wherein said object to be marked material, deflection of the light beam according to any one of claims 2, 3, 4, 5 or 6, characterized in that the surface layer by irradiation of light beams may carved Control method. 8. The method of controlling deflection of a light beam according to claim 7 , wherein the material to be marked is a resin plate. Wherein said marking material according to claim 7, characterized in that with a color different from the surface layer of the base layer can be peeled off by the light beam irradiated on the upper surface of the base layer also <br /> Is the deflection control method of the light beam according to any one of 8 . Wherein said object to be marked material, light as claimed in any one of claims 2, 3, 4, 5 or 6, wherein the surface color by irradiation of a light beam is susceptor that changes Beam deflection control method. 11. The method of claim 1 1 wherein the reference pattern and said irradiation pattern is characterized in that the same pattern
0. The deflection control method of a light beam according to any one of 0 . 12. An image density change point is searched for along the outer circumference of the obtained image area based on the image data, and then an image density change point is searched for along a line inside a fixed distance from the outer circumference. The deflection control method for a light beam according to any one of claims 1 to 11 , characterized in that the grid point coordinates in the image data are obtained by repeating the above process. 13. An image density change point is searched for along the outer periphery of the obtained image area based on the image data, and then an area defined by coordinates obtained from the image density change point on the outer periphery is searched. Repeat to search the boundary, the light beam deflection control method according to any one of claims 1 to 11, wherein the determination of the grid point coordinates in the image data. 14. After searching for an image grayscale change point along the outer periphery of the obtained image area based on the image data, the next 2 on the opposite side obtained from the image grayscale change point on the outer periphery. It is characterized in that an intersection of line segments formed from a set of coordinates is calculated, and a search is performed on an outer peripheral line of a region located at a constant distance with the intersection as the center to obtain grid point coordinates in the image data. Item 12. A light beam deflection control method according to any one of items 1 to 11 . 15. After searching for an image density change point along the outer circumference of the obtained image area based on the image data, then searching for an image density change point along a line inside a certain distance from the outer circumference. Then, from the simultaneous equations obtained from the vertical line segment and the horizontal line segment obtained from these change points,
12. The grid point coordinates are obtained, as claimed in any one of claims 1 to 11.
A method for controlling deflection of a light beam according to any one of 1. 16. A method according to claim 12 for the two image gray change point corresponding to the line segment width, and obtains the lattice point coordinates using the center point coordinates of the two points, 13 and 14 also
Is a deflection control method of a light beam according to any one of 15 . 17. Based on the image data, an image density change point is searched for along an outer peripheral portion of the image area or an inner periphery separated from the image area by a constant distance, and a plurality of lines are searched at a constant minute distance. The deflection control method of the light beam according to claim 12, 13 , 14 or 15 , wherein the coordinate value of the image grayscale change point is set. 18. The radiation pattern or in correspondence with the image acquiring position of the reference pattern, the light beam deflection control method according to any one of claims 1 to 17, characterized by changing the deflection correction data. 19. A stereolithography apparatus for stacking a plurality of solidified layers formed by irradiating and solidifying a material to be solidified with a light beam to form a desired three-dimensional shape, comprising a reference pattern arranged on a predetermined plane. partial image及<br/> beauty, wherein the object to be marked top disposed on the plane
Partial image of the reference pattern illumination pattern drawn by irradiating a light beam on the position of the reference image data obtained by acquiring a partial image of the acquired in the same imaging position, the reference image
And obtained Ru image acquiring means and the data and the illumination image data, corresponding to the same imaging position obtained by the image acquisition unit
Correction data calculation means for comparing the reference image data of the partial image with the irradiation image data and calculating deflection correction data of the light beam based on the comparison result, and the deflection correction data obtained by the correction data calculation means. An optical modeling apparatus comprising: a deflection control unit that controls the deflection of the light beam based on the above.