JP4699051B2 - Stereolithography equipment - Google Patents

Description

  The present invention relates to an optical modeling apparatus that models a three-dimensional object by irradiating a predetermined photocurable resin with light such as laser light, and more particularly to an optical modeling apparatus suitable for modeling an object having a micron-order size.

  Based on three-dimensional shape data (for example, CAD data) representing a three-dimensional object, cross-sectional shape data representing the shape of a plurality of slice cross sections from the lowermost end to the uppermost end at a predetermined interval is generated. By sequentially forming a flat resin layer that represents each slice cross section based on the cross-sectional shape data by curing the photocurable resin, the resin layer is sequentially laminated each time the resin layer is formed. An optical modeling technique for modeling a model corresponding to the three-dimensional object and an optical modeling apparatus for realizing the same are already known (for example, see Patent Documents 1 to 3). Various methods have been proposed for modeling techniques. In any case, for example, exposure light such as laser light is irradiated to an uncured photocurable resin within an irradiation range determined by cross-sectional shape data. In general, the formation of the resin layer and the lamination of the resin layer are repeated to obtain a shaped article.

JP 2004-249508 A JP 2004-223789 A Japanese Patent No. 3294833

  The optical modeling technique is a technique that has been conventionally used in various product prototyping scenes because it can model a model that becomes an embodiment model relatively easily from design data. In recent years, the object of modeling has become smaller, and research on applying the technology to so-called micromachining has become active.

  In the case of micromachining, since the size required as the overall size of the modeled object is about several hundreds μm at the maximum, the component part is required to be modeled with a size that is at least one order smaller. In order to realize this, it is necessary to realize a modeling accuracy of several tens of μm or less, more preferably about 10 to 20 μm or less.

  In the optical modeling apparatus, it is considered that the planar resolution at the time of exposure is one of the factors that influence the modeling accuracy. Since the planar resolution is determined depending on the focus state of the exposure light, it is necessary to always keep the focus on the surface of the resin layer to be exposed during modeling. However, as the lamination of the resin layers progresses, deviations from the set values of the thicknesses of the respective layers accumulate, and the focus may not coincide with the surface of the resin layer. In addition, the focus may not match due to the height variation or unevenness of the base surface during modeling. Moreover, even if such a shift in the focus state occurs, if this cannot be grasped in the middle of modeling, it is necessary to actually complete the model and directly determine the quality of the model based on the actual product. , Improvement in yield and productivity will be hindered.

  In Patent Document 1, an optical unit for focusing is provided, and the focus state is adjusted by detecting reflected light of light emitted from a light source provided in the optical unit by a detection means provided in the optical unit. An optical modeling apparatus capable of performing the above is disclosed. However, in the case of such an aspect, it is difficult to realize high-precision focusing because it does not determine whether the focus state of the exposure light actually used for exposure is good or bad.

  In Patent Document 2, an optical modeling apparatus having an optical system that scans exposure light with a galvanometer mirror, a beam splitter is arranged in the middle of the exposure light irradiation optical system, and on the branch optical path of the beam splitter An optical modeling apparatus is disclosed, in which an imaging camera is arranged and an illumination light source for observation is arranged below a substrate serving as a modeling stage. In the optical modeling apparatus, when illumination light is irradiated from the illumination light source during modeling, the transmitted light that has passed through the glass substrate and the modeled object is guided to the imaging camera on the branch optical path by the beam splitter, and the image is viewed. The modeling state can be confirmed. However, in the case of this aspect, there is a problem that an illumination light source is essential and that the stage and the modeled object are limited to materials that transmit illumination light.

  Patent Document 3 discloses a so-called free liquid level apparatus that performs modeling by repeating exposure of the liquid level and lowering of the stage in a tank filled with resin in advance. In such an apparatus, although a means for detecting the liquid level is provided, no means for observing the modeling state is provided.

  The present invention has been made in view of the above problems, and can provide a stereolithography apparatus suitable for micromachining while being able to confirm a focus state during modeling and correcting the state. Objective.

In order to solve the above-mentioned problems, the invention of claim 1 is to sequentially form a plurality of flat resin layers by curing a predetermined resin, and sequentially stack the resin layers each time the resin layers are formed. By doing so, it is an optical modeling device that models a predetermined three-dimensional modeled object, and each time a three-dimensional modeled object is modeled, a storage part that stores the resin, and each of the resin layers is formed. Supply means for supplying a predetermined amount of the resin from the storage part to the modeling part, smoothing means for smoothing the resin supplied by the supply means, and light emitted from the light source by the modulation means An irradiation unit that cures the resin by irradiating the resin smoothed on the modeling part after modulation, and the reflected light of the light irradiated to the resin from the irradiation unit is imaged and visible Observation means for The shaping part is provided so as to be vertically movable by a predetermined drive mechanism, the observation means is provided in the middle of the optical path in the irradiation means, and an optical branching means for branching the reflected light from the optical path; an imaging means for imaging the reflected light split by the optical splitting means comprises a display means for visibly displaying the image captured by the imaging means, the plant to the shaping part by the supply means Supply of a fixed amount of the resin, smoothing of the resin by the smoothing means, formation of the resin layer by exposing the resin with the light irradiated by the irradiation means, and the predetermined driving mechanism It adapted to form the 3D object by by repeatedly performing descent of the shaped portion of the distance corresponding to the thickness of the resin layer to be formed next, previous The focus position of the light can be adjusted by driving the drive mechanism in accordance with the focus state of the light in the resin layer or the smoothed resin displayed on the display means during exposure with light. It is characterized by that.

  Invention of Claim 2 is an optical modeling apparatus of Claim 1, Comprising: In the relationship between the height position of the said resin layer or the smoothed resin in the case of the exposure by the said light, and the focus position of the said light Accordingly, the driving mechanism is driven to adjust the focal position of the light.

  Invention of Claim 3 is an optical modeling apparatus of Claim 1 or Claim 2, Comprising: While the said irradiation means is fixedly installed in the predetermined position, the said irradiation is carried out at the start of modeling in the said modeling part. Modeling is performed after the focal position of the light emitted from the means is matched with the surface of a predetermined modeling substrate fixed to the modeling unit.

  Invention of Claim 4 is an optical modeling apparatus of Claim 3, Comprising: Prior to the start of modeling in the said modeling part, the smooth surface by predetermined resin can be formed in the modeling surface whole surface of the said modeling base material. It is characterized by that.

  According to the first to fourth aspects of the present invention, since the deterioration of the modeling accuracy of the resin layer is prevented, the modeling accuracy of the entire modeled object can be kept higher than when no fine adjustment is performed. Further, since fine adjustment can be performed in the middle of the modeling, the yield and productivity of the modeled object can be improved as compared with the case where the quality of the modeled object is judged only after the entire modeling is completed.

  In particular, according to the second aspect of the present invention, since the focal position can be finely adjusted without sequentially adjusting at the time of exposure, it is possible to prevent the modeling accuracy of the resin layer from being lowered.

  In particular, according to the invention of claim 3 or claim 4, it is possible to absorb the change with time of the optical modeling apparatus and perform modeling always with high accuracy.

  In particular, according to the fourth aspect of the present invention, even if the modeling base material has a height variation or unevenness variation, these effects are canceled by the underlayer, so that a highly accurate modeling can be performed.

<Device overview>
FIG. 1 is a schematic cross-sectional view schematically showing a configuration of an optical modeling apparatus 100 according to the present embodiment. The optical modeling apparatus 100 repeats exposure based on shape data on a photo-curing resin (hereinafter, also simply referred to as “resin”) applied to a predetermined thickness in a predetermined application region, along with the lamination of the resins, It is an apparatus that can form a three-dimensional object by a so-called additive manufacturing method. The optical modeling apparatus 100 includes a light source unit 10, an illumination optical system 20, a projection optical system 30, an image plane observation system 40, a modeling unit 50, a supply unit 60, a smoothing unit 70, and a beam observation unit 80. And a vacuum fixing unit 90 and a control computer PC. Note that FIG. 1 merely schematically shows the configuration of each part, and the magnitude relationship of each component does not necessarily reflect the actual state.

  The light source unit 10 emits exposure light from a predetermined light source 11 via a heat ray cut filter 12. The kind of the light source 11 is not specifically limited, For example, an appropriate thing can be used in the range which can harden resin used for modeling, such as a laser, a lamp | ramp, and LED. That is, light having an appropriate wavelength such as UV light, visible light, or infrared light can be used as the exposure light. Moreover, the aspect formed so that several types of light sources can be switched may be sufficient. The exposure light emitted from the light source 11 is guided to the illumination optical system 20 by the optical fiber 13.

  Although the detailed illustration of the illumination optical system 20 is omitted, the exposure light from the light source is appropriately reflected and irradiated to a modulation means 21 such as a DMD (digital mirror device), and the reflected light is illustrated. The light is incident on the projection optical system 30 while adjusting with a predetermined lens group.

  Here, the case where DMD is used as the modulation means 21 will be outlined. In the DMD, unit blocks in which minute mirrors are two-dimensionally arranged are arranged one-dimensionally, and a drive memory cell corresponding to each mirror is provided, and an ON to the drive memory cell is provided. By changing the attitude of each mirror in accordance with the / OFF writing state, ON / OFF switching of the exposure light incident on the projection optical system 30 can be performed for each mirror. Since the presence or absence of irradiation of the exposure light in the minute area can be set corresponding to each mirror, the modeling unit 50 described later performs exposure with the irradiation range of the reflected light from each mirror as an exposure unit. I can do it. Then, by setting ON / OFF of writing to the drive memory cell corresponding to each mirror according to the content of the cross-sectional shape data representing each slice cross-section, the irradiation area of the exposure light can be determined according to the data. Since it can be determined according to the expressed cross-sectional shape, only the range determined according to the cross-sectional shape can be exposed. When such a DMD is used, for example, an exposure size area of 1024 pixels × 768 pixels can be exposed.

  The modulation means 21 is not limited to one that performs two-dimensional control such as DMD, but one that performs one-dimensional control such as a liquid crystal shutter or one that controls a point beam. The mode to be used may be used. However, it goes without saying that two-dimensional control such as DMD is preferable from the viewpoint of exposure efficiency.

  The projection optical system 30 is responsible for the exposure process using the exposure light incident from the modulation means 21. The projection optical system 30 irradiates the exposure light from the objective lens 34 onto the modeling base 51 of the modeling unit 50 in a focused state while adjusting the exposure light with the predetermined lens group 31 and the mirror group 32. The reflected light from the modeling unit 50 is received by the objective lens 34, branched by the beam splitter 33 provided on the optical path of the projection optical system 30, and guided to the image plane observation system 40.

  In the optical modeling apparatus 100 according to the present embodiment, the objective lens 34 is fixed to the base 1 and arranged so as to irradiate exposure light vertically downward. That is, exposure is performed with the direct irradiation source fixed. In this mode, compared to the case where exposure is performed by moving or scanning the irradiation source, the focus state is stabilized by fixing the optical path length, the amount of light fluctuation caused by movement, etc. It has advantages such as low vibration. If a method of moving or scanning the irradiation source is adopted, if the stacking thickness is 20 μm or less and the planar resolution is 5 μm or less, the scanning deviation of the exposure light affects the modeling accuracy, and the accuracy is further improved. I can't expect. That is, the arrangement mode of the projection optical system 30 according to the present embodiment is a mode that contributes to the improvement of the planar resolution during modeling.

  Furthermore, as will be described later, the optical modeling apparatus 100 has a modeling unit 50 in which a resin is smoothly applied to the modeling substrate 51 in another place, which is arranged immediately below the objective lens 34 by the horizontal drive mechanism 54. It is configured to perform the above exposure. That is, since no other components are interposed between the objective lens 34 and the modeling substrate 51, exposure is performed with the exposure target surface on the modeling substrate 51 sufficiently close to the objective lens 34. Is done. Preferably, the distance between them is 20 μm or less.

  The image plane observation system 40 receives the light from the beam splitter 33, that is, the reflected light from the modeling unit 50 by the CCD camera 42 while adjusting the predetermined lens group 41, and displays the received image on the monitor 43. . The CCD camera 42 has a sufficient sensitivity with respect to the wavelength of the exposure light. As a result, when exposure is performed with exposure light, the reflected light is received so that the state during exposure (modeling state) can be directly observed.

  In the stereolithography apparatus 100 according to the present embodiment, the focus position can be adjusted using such an image plane observation system 40. This will be described later.

  The modeling unit 50 is a place where a three-dimensional object is modeled. In the modeling part 50, the modeling tank 53 which has the stage 52 which can fix the modeling base material 51 used as the base member in the case of modeling inside is provided. As the modeling substrate 51, a glass substrate or other appropriate flat plate member can be used. It may be selected and used as appropriate depending on the type of resin, the structure and size of the shaped article. The modeling area in the modeling substrate 51 varies depending on the configuration of the modulation unit 21 and the projection optical system 30, but if a DMD having an exposure area of 1024 pixels × 768 pixels is used for the modulation unit 21, for example, Modeling is possible in an area of 15 cm × 15 cm.

  FIG. 2 is a diagram illustrating the state of modeling in the optical modeling apparatus 100. In modeling, based on the cross-sectional shape data, by repeating the application and exposure of the resin layer on the modeling substrate 51, the modeling object 53, which is a laminate of resin layers cured by exposure, is formed in the modeling tank 53. The uncured portion of the resin P is accumulated step by step. When the viscosity of the resin is low, the cured portion is immersed in the resin liquid collected in the modeling tank 53. In any case, the three-dimensional object formed on the modeling substrate 51 can be obtained by lifting the modeling object M from the modeling tank 53 together with the modeling substrate 51 when the processing for all the cross sections is completed. Become. In this case, uncured resin may adhere to the periphery of the three-dimensional object, but these are removed by a predetermined cleaning means or the like.

  The modeling tank 53 is movable in the horizontal direction (preferably in the XY biaxial direction) by the horizontal drive mechanism 54. In the optical modeling apparatus 100 according to the present embodiment, the supply unit 60 responsible for supplying the resin to the modeling unit 50, the smoothing unit 70 responsible for smoothing the supplied resin, and the smoothed resin The objective lens 34 responsible for the exposure is provided at different positions, and the modeling unit 50 is sequentially moved by the horizontal drive mechanism 54 to perform the respective processes. Therefore, the modeling part 50 is configured to be movable between these parts by the horizontal drive mechanism 54. The horizontal drive mechanism 54 can be realized by a known drive mechanism such as a ball screw. Preferably, the driving accuracy by the horizontal driving mechanism 54 is ± 0.5 μm or less. The stage 52 can be moved in the vertical direction (Z-axis direction) in the modeling tank 53 by a vertical drive mechanism (elevator) 55. It is preferable that the vertical drive mechanism 55 can realize precise positioning with a drive accuracy of ± 0.2 μm. This is possible by using a known linear scale, for example.

  In the modeling part 50, it respond | corresponds to the cross-sectional shape according to cross-sectional shape data with respect to the photocurable resin apply | coated by the predetermined thickness on this modeling base material 51 by the effect | action of the supply part 60 and the smoothing part 70 which are mentioned later By irradiating from the objective lens 34 the exposure light whose irradiation range is determined, only the irradiation range of the resin is cured, thereby realizing a partial cross section with the three-dimensional object to be modeled. The formed resin layer is formed. Strictly speaking, when a resin layer is already formed, a new resin is applied on the resin layer. However, in the present embodiment, for the sake of simplicity of expression, a resin layer is formed “on the modeling substrate 51” or “on the modeling substrate 51” for these aspects including the case described above. Or an expression such as irradiating exposure light.

  When such exposure is performed, the vertical drive mechanism 55 lowers the stage 52 together with the resin laminate formed thereon by a predetermined distance, and the same processing is performed on the next cross section. By repeating this process from the lowermost part to the uppermost end of the three-dimensional object by a predetermined step, a three-dimensional object is obtained.

  The supply unit 60 is responsible for supplying a predetermined amount of photocurable resin to the modeling unit 50 during such modeling. Specifically, a predetermined amount of modeling resin stored in the pressurized tank 62 is supplied in a state where the horizontal driving mechanism 54 is driven and the modeling unit 50 is disposed at a position directly below the dispenser nozzle 61. Through the dispenser nozzle 61 fixed to the base body 1, the material is supplied onto the modeling substrate 51 of the modeling unit 50. The supply amount of the resin for one supply can be adjusted by controlling and controlling the pressurization state in the pressurization tank 62 and the opening and closing of the dispenser valve 64 by the dispenser controller 65. The pressurized tank 62 preferably has a stirring function, and can perform a stirring operation in response to a predetermined operation instruction. Thereby, the state of the resin in the pressurized tank 62 can be kept more uniform. In addition, since no other constituent elements are interposed between the dispenser nozzle 61 and the modeling substrate 51 when supplying the resin, the resin in a state where the dispenser nozzle 61 and the modeling substrate 51 are sufficiently close to each other. Supply is realized. Moreover, the supply mode of the resin in performing modeling for one cross section can be appropriately determined according to the type of resin, the shape of the cross section to be modeled, and the like. Accordingly, the supply amount is determined as appropriate.

  The smoothing unit 70 performs a process of smoothing the resin supplied from the supply unit 60 by the recoater 71 provided on the base 1. The recoater 71 is also called a squeegee, a knife edge, or the like. For example, the recoater 71 is a member in which at least a tip portion has a substantially flat plate shape.

  The smoothing of the resin in the smoothing unit 70 is performed by moving the modeling unit 50 after the resin is supplied onto the modeling substrate 51 by the supply unit 60 to a position directly below the smoothing unit 70 by the horizontal drive mechanism 54. Done. When the recoater 71 provided so as to be able to advance and retreat is moved from one end above the modeling substrate 51 to the other end by the action of a predetermined driving means (not shown) after the arrangement relationship is realized, the modeling substrate The resin applied on 51 is made uniform by being scraped off by the recoater 71 or the like. The excess resin scraped off is discharged to a discharge unit (not shown).

  At this time, the distance between the recoater 71 and the modeling base 51 (or the resin layer cured immediately before) when the recoater 71 moves defines the thickness when the applied resin is subjected to exposure. However, in the optical modeling apparatus 100 according to the present embodiment, the stage 52 (that is, the modeling substrate 51) can be precisely positioned by the vertical drive mechanism 55 as described above, and at the time of smoothing. Since no other components are interposed between the recoater 71 and the modeling substrate 51, smoothing in a state where the recoater 71 and the modeling substrate 51 are sufficiently close to each other is realized. Preferably, a state in which the distance between the two is about 10 μm is realized. After the exposure of the resin layer, the vertical drive mechanism 55 lowers the stage 52 (that is, the modeling substrate 51) by a distance corresponding to the thickness prior to the application of the next resin. As a result of repeated application of this resin, exposure, and lowering of the stage 52, the optical modeling apparatus 100 according to the present embodiment is about 10 μm in thickness, which is very fine compared to the conventional optical modeling apparatus. The resin layer can be formed with a thickness of.

  Here, the meaning of the arrangement relationship of the objective lens 34 (projection optical system 30), the modeling unit 50, the supply unit 60, and the smoothing unit 70 described above will be described. In general, from the viewpoint of improving modeling accuracy in an optical modeling apparatus, it is necessary to accurately align the focus of the exposure light with the resin surface. For this purpose, the distance between the objective lens 34 and the irradiation position is made as short as possible. Is preferred. In order to improve the accuracy of coating thickness of the resin, it is preferable that the supply means for supplying the resin and the smoothing means for smoothing the supplied resin are as close as possible to the modeling surface.

  Temporarily, if a mechanism that moves the projection optical system of exposure light while fixing the modeling part is adopted, the supply means and smoothing means operate between the modeling part and the projection optical system when supplying and smoothing the resin. Need to be made. In that case, the arrangement of the supply means and the smoothing means is greatly restricted. It is possible to employ a mechanism that retracts the projection optical system during the operation of the supply means and the smoothing means, and conversely retracts the supply means and the smoothing means at the time of exposure. Of course, the exposure accuracy of the exposure light is inferior to that of the aspect in which the projection optical system is fixed, which is not preferable from the viewpoint of improving the modeling accuracy.

  On the other hand, in the optical modeling apparatus 100 shown in FIG. 1, the supply part 60 for supplying resin, the smoothing part 70 which smoothes the supplied resin, and exposure to the smoothed resin is performed. The objective lens 34 to be performed is provided at a separate position in substantially the same horizontal plane, and a modeling unit 50 on which modeling is performed is configured to be movable by a horizontal drive mechanism 54 below these units. Become. And in the process in each part, it has the aspect which moves the modeling part 50 to the part directly under each part sequentially by this horizontal drive mechanism 54, and arranges it facing each. Thereby, in the optical modeling apparatus 100, as described above, in the processes of resin supply, smoothing, and exposure, the components responsible for other processes are provided between the modeling unit 50 and the respective units responsible for the respective processes. Each process is performed in the state which made the modeling part 50 as close as possible to each part, without interposing. This is one of the reasons why high modeling accuracy is realized in the optical modeling apparatus 100 as compared with the conventional art.

  The beam observation unit 80 is provided for observing the state of the exposure light emitted from the objective lens 34. The beam observation unit 80 determines the power, shape, light amount distribution, etc. of the exposure light by a predetermined observation means (not shown) at a predetermined observation position (for example, an exposure imaging position immediately below the objective lens) on the optical path of exposure light. Observe. In addition, the beam observation unit 80 may be configured to be attached to the modeling unit 50 as illustrated in FIG. 1 and to be arranged at the observation position by driving the horizontal driving mechanism 54, or an independent unit. It may be a mode that can be moved by the driving means. Alternatively, it may be configured to be detachable from the modeling unit 50, attached only when necessary, and removable at other times. In this case, the observation means 80 that is not in use can be protected from contamination. Regardless of which mode is used, the exposure light actually used for exposure is directly observed at the position where the exposure is performed. Therefore, when performing modeling, the state of the exposure light used can be accurately grasped. I can do it.

  The vacuum fixing unit 90 is provided for adsorbing and fixing the modeling substrate 51 to the stage 52. FIG. 3 is a conceptual diagram illustrating such suction fixation. In the stereolithography apparatus 100 according to the present embodiment, the vacuum pump 91 is provided with a plurality of suction holes 94 (not shown in FIG. 1) provided in the stage 52 by an exhaust pipe 93 provided with a solenoid valve 92 on the way. (Fig. 3 (a)). When the vacuum pump 91 is operated and the solenoid valve 92 is opened while the modeling base 51 is placed on the stage 52, the modeling base 51 is fixed to the stage 52 by the negative pressure in the suction hole 94.

  Further, when the area of the modeling surface 51 s of the modeling substrate 51 is smaller than the area of the mounting surface 52 s of the stage 52, depending on the modeling substrate 51, all the suction holes on the stage 52 cannot be closed. The fixing cannot be realized simply by placing the modeling substrate 51 on the stage 52 as in 3 (a). In this case, as shown in FIG. 3B, a mask 95 is prepared by hollowing out the central portion according to the size of the modeling substrate 51 (or the same state can be obtained by combining). The mask 95 is placed around and the suction hole 94 that cannot be covered by the modeling substrate 51 is closed by the mask 95, thereby fixing the modeling substrate 51.

  In addition, as a mode of fixing the modeling substrate 51 with respect to the stage 52, a mode in which a fixing tool such as a fixing claw or a sandwiching member is provided on the stage and a fixing frame, a mode in which the model 52 is fixed by a magnetic force of a magnet, and the like are also considered. It is done. However, in the former case, the flatness in the center portion is not sufficiently obtained particularly when the modeling base material is on the sheet, and the fixing tool and the fixing frame interfere with the operation of the recoater 71 when the recoater 71 is operated. This is not preferable because there is a possibility that the fixing tool or the fixing frame needs to be moved according to the size of the modeling base material, and there are problems such as troublesome operation and insufficient positional accuracy. Furthermore, in the latter case, if the modeling substrate needs to be a magnetic material, or if the photocurable resin used for modeling contains a magnetic material, the dispersion state and orientation of the magnetic material in the presence of magnetic force There is a problem that the characteristics are biased, which is not preferable because the cost increases.

  On the other hand, in the optical modeling apparatus 100 according to the present embodiment, the mask 95 is made of any material as long as it is flat and thinner than the modeling substrate 51 and can cover the stage 52. However, the modeling substrate 51 can be reliably fixed without causing interference with the recoater 71. That is, even when the size of the modeling substrate 51 is smaller than the stage 52, the modeling substrate 51 can be reliably fixed to the stage 52 simply and inexpensively.

  The control computer PC is provided for controlling the operation of each part of the optical modeling apparatus 100. A general-purpose personal computer can be used as the control computer PC. The control computer PC gives a predetermined operation signal to the control target element responsible for controlling the operation of each unit described above according to a predetermined control program (not shown), and receives a response signal from each unit, whereby the optical modeling apparatus 100 Realize the modeling process. For example, cross-sectional shape data representing a slice cross section of a three-dimensional object to be modeled, which has been created in advance by the control computer PC or another computer not shown, is acquired, and modulation means is obtained based on the data relating to each cross section The control computer PC is responsible for various operation controls including the processing of setting the ON / OFF state of the exposure light in 21 and performing exposure according to the cross-sectional shape.

  By using the optical modeling apparatus 100 having such a configuration, as illustrated in FIG. 6, it is possible to realize high-precision modeling with a laminated thickness of 10 μm and a planar resolution of 2 μm. That is, the optical modeling apparatus according to the present embodiment is a suitable apparatus for micromachining.

  In the optical modeling apparatus 100, the modeling unit 50 is provided so as to be horizontally movable, and the objective lens 34 (projection optical system 30), the supply unit 60, and the smoothing unit 70 are independently and substantially in the same horizontal plane above the modeling unit 50. Since it is arranged, when maintenance of each part becomes necessary, it becomes possible to easily access the target part simply by retracting the modeling part 50 from the position. In the optical modeling apparatus according to the present embodiment, including that the apparatus configuration is simple, an improvement in maintainability is realized.

<Adjusting the focus>
Next, adjustment of the focus of the exposure light in the optical modeling apparatus 100 according to the present embodiment will be described.

  FIG. 4 is a diagram for explaining a focus state in the optical modeling apparatus 100 according to the present embodiment. First, when modeling is started, the focus F is made to coincide with the surface of the modeling substrate 51 before the formation of the resin layer PL as shown in FIG. This is to absorb changes with time of the optical modeling apparatus 100. Thereafter, as shown in FIG. 4B and FIG. 4C, the formation and exposure of the resin layer PL having a constant thickness (for example, 10 μm) are repeated. Must have the same focus. More specifically, since the objective lens 34 is fixed to the base 1, the absolute focus position in space (the height indicated by the dotted line in FIG. 4) may be considered unchanged. Therefore, the coincidence of the focus on the resin layer surface is realized by making the absolute height in the space of the resin layer surface coincide with the focus position. Therefore, ideally, any resin layer PL can be focused by lowering the stage 52 by a distance that exactly matches the thickness while repeatedly forming the resin layer PL with a completely constant thickness. Should match the surface.

  However, in actuality, as the lamination of the resin layer PL progresses, as shown in FIG. 4D, the deviation from the set value of the thickness of each layer accumulates, and the focus F matches the surface of the resin layer PL. It can happen. In addition, the focus may not match due to the height variation or unevenness of the base surface during modeling.

  On the other hand, in the optical modeling apparatus 100, the exposure light is irradiated so that the uncured resin layer applied and formed on the modeling substrate 51 is in focus, and the reflected light is received by the objective lens 34. Then, the beam is split by the beam splitter 33, guided to the image plane optical system 40, and received by the CCD camera 42. That is, since the exposure light irradiated at the time of exposure is used as illumination light for the resin layer to be exposed, exposure is performed on the monitor 43 of the image plane observation system 40. It is possible to observe the state of the resin layer in real time. Thereby, at the time of exposure, the success or failure of the focus state as shown in FIG. 4 can be easily determined. In addition, it is not necessary to provide a separate illumination light source, and the modeling base 51 used for modeling and the material of the resin are not restricted by the illumination light source. In addition, although light is not irradiated between exposure, since exposure time is normally set to about 0.5 to 1 second, the judgment which concerns can be performed without a problem in exposure.

  That is, in the optical modeling apparatus 100 according to the present embodiment, when the resin layer corresponding to a certain cross section is being exposed, it is confirmed whether or not the focus at that time coincides with the resin layer surface. Is possible. Of course, at that time, the focus of the resin layer can no longer be adjusted, but after the exposure of the resin layer is completed, the next resin layer is exposed for the next cross section until the control is performed. By inputting a predetermined fine adjustment operation instruction to the computer PC and causing the vertical drive mechanism 55 to perform a fine adjustment operation and finely adjusting the height position of the stage 52, the focus position corresponding to the observation result by the monitor 43 is adjusted. Fine adjustment is possible. Such fine adjustment can be performed, for example, when the stage 52 is lowered prior to the formation of the resin layer, or after that until exposure.

  That is, although the modeling accuracy of the resin layer that has already been exposed in a state of defocus cannot be improved, by performing such fine adjustment, a decrease in the modeling accuracy of the subsequent resin layer is prevented. The modeling accuracy of the entire modeled object can be kept higher than when fine adjustment is not performed. In addition, since fine adjustment can be performed in the middle of modeling in this way, the yield and productivity of the model can be improved compared to the case where the quality of the model is judged only after the entire modeling is completed. .

<Modification>
In FIG. 1, the smoothing unit 70, the objective lens 34, and the supply unit 60 are arranged in order from the left in substantially the same horizontal plane above the horizontal movement region of the modeling unit 50, but this is essential in the present invention. This is not an aspect. That is, as long as the modeling part 50 is an aspect in which these parts can be individually approached, the arrangement of the parts may be different from the aspect of FIG. For example, the arrangement order of each part may be changed, and the aspect arrange | positioned two-dimensionally in the substantially the same horizontal surface may be sufficient.

  In the above-described embodiment, when modeling, first, the focus position is matched on the modeling substrate 51, and then a resin layer for modeling is formed, as shown in FIG. As described above, when the modeling substrate 51 is inclined, it is difficult to accurately stack the resin layer even if the resin layer is formed as it is. However, the inclination is exaggerated in FIG. In such a case, as shown in FIG. 5B, the base layer BL may be once provided on the entire modeling surface of the modeling substrate 51 so that the surface thereof is horizontal, and then modeling may be performed. For example, the base layer BL may be an embodiment in which a resin used for modeling is used as it is. By performing modeling based on the base layer BL provided in this way, even if the modeling base material has variations in height or irregularities, these effects are canceled by the base layer BL, and high-precision modeling is performed. I can do it.

  In the above-described embodiment, the focus state correction is performed while observing the resin layer surface with the image plane observation system 40. However, the stacking thickness (or height) of the stacking progresses. If the deviation, that is, the positional deviation of the resin layer to be exposed from the focal position can be predicted from the type, density, viscosity, etc. of the resin, or if the statistical tendency is known, the focus position is small. For adjustment, the moving distance of the stage 52 may be changed according to the number of stacked layers. For example, a data set (data table) in which the number of layers and fine adjustment amount are associated, and a function of fine adjustment amount having variables such as the number of layers and physical properties of the resin are stored in the control computer PC. An aspect in which the fine adjustment amount obtained is appropriately read may be employed. Such a data set may be determined for each modeling position. Alternatively, it is also possible to store the results of the adjustments performed in the manner as described in the above-described embodiment in the control computer PC as the above-described data set so as to be used for later modeling. . Or you may use combining the above aspects.

  FIG. 6 is an SEM (scanning electron microscope) image of a modeling sample created using the optical modeling apparatus 100 according to the above-described embodiment. Modeling was performed using laser light having a wavelength of 405 nm as a light source and using an acrylate-based resin (viscosity of 1500 to 2500 mPa · s at 25 ° C.) as a photocurable resin. Such a modeling sample is formed to a height of about 70 μm by stacking seven resin layers each having a bottom surface of 26 μm square and a top part of 5 μm square and a thickness of about 10 μm on a solid surface. Is. Although detailed illustration is omitted, the modeling error from the design data is about 2 μm or less.

  That is, in the stereolithography apparatus 100 according to the present embodiment, a stacking thickness of 10 μm and a planar resolution of 2 μm could be realized.

It is a cross-sectional schematic diagram which shows schematically the structure of the optical modeling apparatus 100 which concerns on this Embodiment. It is a figure which illustrates about the mode of modeling in the optical modeling apparatus. It is a conceptual diagram explaining adsorption fixation. 3 is a diagram for explaining a focus state in the optical modeling apparatus 100. FIG. It is a figure explaining the focus adjustment in case the modeling base material 51 has an inclination. It is a figure which shows the SEM image of the modeling sample created using the optical modeling apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base | substrate 10 Light source part 11 Light source 20 Illumination optical system 21 Modulation means 30 Projection optical system 33 Beam splitter 34 Objective lens 40 Image surface observation system 42 CCD camera 43 Monitor 50 Modeling part 51 Modeling base material 52 Stage 53 Modeling tank 54 Horizontal drive mechanism 55 Vertical Drive Mechanism 60 Supply Unit 61 Dispenser Nozzle 70 Smoothing Unit 71 Recoater 80 Beam Observation Unit 90 Vacuum Fixing Unit 91 Vacuum Pump 94 Adsorption Hole 95 Mask 100 Stereolithography Device BL Underlayer M Molded Object P Resin PC Control Computer PL Resin layer

Claims (4)

Light for forming a predetermined three-dimensional structure by sequentially forming a plurality of flat resin layers by curing a predetermined resin and sequentially stacking the resin layers each time the resin layer is formed A modeling device,
A modeling part where a three-dimensional model is modeled,
A reservoir for storing the resin;
Supply means for supplying a predetermined amount of the resin from the storage portion to the modeling portion each time each of the resin layers is formed ;
Smoothing means for smoothing the resin supplied by the supply means;
Irradiation means for curing the resin by irradiating the resin smoothed on the modeling part after modulating the light emitted from the light source by the modulation means;
An observation unit that forms an image of reflected light of the light irradiated on the resin from the irradiation unit and makes it visible;
With
The modeling part is provided to be vertically movable by a predetermined drive mechanism,
The observation means is
An optical branching means provided in the middle of the optical path in the irradiating means, and branching the reflected light from the optical path;
Imaging means for imaging the reflected light branched by the optical branching means;
Display means for displaying a picked-up image by the image pickup means so as to be visible;
Including
Supply of the predetermined amount of resin to the modeling part by the supply unit, smoothing of the resin by the smoothing unit, and exposure of the resin by the light irradiated by the irradiation unit The three-dimensional structure is formed by repeatedly performing the formation of the layer and the lowering of the modeling portion at a distance corresponding to the thickness of the resin layer to be formed next by the predetermined driving mechanism,
The focus position of the light can be adjusted by driving the drive mechanism according to the focus state of the light in the resin layer or the smoothed resin displayed on the display means during the exposure with the light. is there,
An optical modeling apparatus characterized by that. The optical modeling apparatus according to claim 1,
The focus position of the light by driving the drive mechanism according to the relationship between the height position of the resin layer or the smoothed resin at the time of exposure with the light assumed in advance and the focus position of the light. Is adjustable,
An optical modeling apparatus characterized by that. The optical modeling apparatus according to claim 1 or 2,
The irradiation means is fixed at a predetermined position,
At the start of modeling in the modeling unit, modeling is performed after matching the focal position of the light irradiated from the irradiation unit with the surface of a predetermined modeling substrate fixed to the modeling unit.
An optical modeling apparatus characterized by that. The optical modeling apparatus according to claim 3,
Prior to the start of modeling in the modeling part, a smooth surface with a predetermined resin can be formed on the entire modeling surface of the modeling substrate.
An optical modeling apparatus characterized by that.