KR20170005368A - three-dimensional printer with automatic exposure control - Google Patents

Abstract

Disclosed in the present invention is a three-dimensional printer having an automatic exposure control function. According to one embodiment, the three-dimensional printer comprises: a container in which a photocurable resin is disposed; a projector including a light source which selectively induces light in at least a part of the photocurable resin to cure at least the part of the photocurable resin; a sensor which is disposed in close proximity of the projector and measures at least one among an intensity, a wavelength and combinations thereof of the light induced in at least the part of the photocurable resin; a database which stores an exposure time of the light induced in the photocurable resin to cure the photocurable resin according to the type of the photocurable resin; and a control unit which extracts the exposure time corresponding to at least one selected among the intensity, the wavelength and combinations thereof measured by the sensor and controls the projector according to a users input or a predetermined program so as to induce the light in at least the part of the photocurable resin for the exposure time. The database stores the exposure time which corresponds to one selected among the intensity, the wavelength and combinations thereof according to the type of the photocurable resin.

Description

A three-dimensional printer with automatic exposure control function (three-dimensional printer with automatic exposure control)

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a three-dimensional printer, and more particularly, to a digital light processing (DLP) type three-dimensional printer having an automatic exposure control function.

A three-dimensional printer is a printer that produces three-dimensional objects. The principles of a three-dimensional printer can be largely divided into two types, a cutting type and a stacking type. The cutting type is a method of obtaining a three-dimensional object having a desired three-dimensional shape by cutting or grinding a lumpy material, and the laminate type is a method of laminating thin layers to realize a desired three-dimensional shaped object.

Examples of the stacking type include fused deposition modeling (FDM), digital light processing (DLP), stereo lithography apparatus (SLA), and selective laser sintering (SLS). The FDM method is a method of forming a three-dimensional shaped object by laminating a plastic material or the like one by one. The DLP method uses a light source, such as UV light, provided by a projector to harden the photo-cured resin gradually, thereby realizing a three-dimensional shaped object. The SLA method is a laser printing method, and is a method of realizing a three-dimensional shaped sculpture through an ultraviolet resin hardened by ultraviolet rays using a laser. The SLA system can be divided into the DLP system and the liquid-based stereolithography system. The SLS method is also referred to as a powder sintering method, in which a powder is melted and sintered using a laser to realize a three-dimensional shaped object.

In DLP method, it is possible to model at one time in plane unit, which is advantageous in speed of modeling. In addition, the DLP method has a merit in that the quality of the 3D sculpture is better than other schemes. In the DLP method, a build tray attached with a basic base of a molding is moved in order to obtain a three-dimensional shaped product, and the basic base is immersed in a container (VAT) containing a photocurable resin. When a light source such as ultraviolet rays is exposed to a photocurable resin through a DLP projector, the photocurable resin is cured. The DLP method is a method in which a three-dimensional sculpture connected to the basic base is obtained step by step. Finally, when the exposure for the three-dimensional molding is completed, the three-dimensional molding can be obtained by moving the build tray and separating the three-dimensional molding from the container and the photocurable resin.

In the case of the DLP method, the intensity, wavelength, etc. of the light source may be different from the initially set value depending on repetitive use of the projector light source. In addition, the photo-curing resin can have a unique light wavelength and light intensity cured according to the type of the photo-curing resin material used. When the exposure conditions such as the exposure time are not adjusted by reflecting the change of the initial setting value, there is a problem that the quality of the output three-dimensional shape is different from the initial quality. For this reason, there is a problem that a user who uses a DLP-type three-dimensional printer must manually change the exposure conditions after confirming the intensity and wavelength of the light source manually before use.

In one embodiment, a three-dimensional printer having an automatic exposure control function is disclosed. The three-dimensional printer includes a container in which a photocurable resin is disposed, a projector including a light source for selectively applying light to at least a portion of the photocurable resin to cure the at least a part of the photocurable resin, A sensor for measuring the intensity of the light applied to the at least a part of the photocurable resin by the light source, a wavelength and a combination thereof, and a sensor for measuring the intensity of the light applied to the photocurable resin, A database for storing the exposure time of the light applied to the photo-curable resin, and the exposure time corresponding to any one of the intensity, the wavelength and the combination of the light measured by the sensor, from the database, Input command or preset program A control unit that controls the projector such that the light is applied to the at least a portion of the photo-curing resin over the exposure time. The database stores the exposure time such that the type of the photo-curable resin corresponds to any one of the intensity of the light, the wavelength of the light, and combinations thereof.

The foregoing provides only a selective concept in a simplified form as to what is described in more detail hereinafter. The present disclosure is not intended to limit the scope of the claims or limit the scope of essential features or essential features of the claims.

1 is a conceptual diagram of a three-dimensional printer having an automatic exposure control function disclosed in the present specification.
2 is a conceptual diagram of a projector used in a three-dimensional printer disclosed in this specification.

Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the drawings. Like reference numerals in the drawings denote like elements, unless the context clearly indicates otherwise. The exemplary embodiments described above in the detailed description, the drawings, and the claims are not intended to be limiting, and other embodiments may be utilized, and other variations are possible without departing from the spirit or scope of the disclosed technology. Those skilled in the art will appreciate that the components of the present disclosure, that is, the components generally described herein and illustrated in the figures, may be arranged, arranged, combined, or arranged in a variety of different configurations, all of which are expressly contemplated, As shown in FIG. In the drawings, the width, length, thickness or shape of an element, etc. may be exaggerated in order to clearly illustrate the various layers (or films), regions and shapes.

When a component is referred to as being " deployed "to another component, it may include the case where the component is directly disposed on the other component, as well as the case where additional components are interposed therebetween.

The description of the disclosed technique is merely an example for structural or functional explanation and the scope of the disclosed technology should not be construed as being limited by the embodiments described in the text. That is, the embodiments are to be construed as being variously embodied and having various forms, so that the scope of the rights of the disclosed technology should be understood to include equivalents capable of realizing the technical ideas.

It is to be understood that the singular " include " or " have " are to be construed as including the stated feature, number, step, operation, It is to be understood that the combination is intended to specify that it is present and not to preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

All terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosed technology belongs, unless otherwise defined. Terms defined in commonly used dictionaries should be interpreted to be consistent with meaning in the context of the relevant art and can not be construed as having ideal or overly formal meaning unless expressly defined in the present application.

1 is a conceptual diagram of a three-dimensional printer having an automatic exposure control function disclosed in the present specification. 2 is a conceptual diagram of a projector used in a three-dimensional printer disclosed in this specification.

Referring to FIGS. 1 and 2, a three-dimensional printer 100 includes a container 110, a projector 120, a sensor 130, a database 140, and a control unit 150.

The container 110 is provided with a photo-curing resin 10. There is no limitation on the material and shape of the container as long as it can provide the light applied by the light source 122 (see FIG. 2) to the photo-curing resin 10. For example, the surface of the container 110 facing the path of the light applied from the light source 122 to the photocurable resin 10 may be made of a material having light transmittance. For convenience of explanation, the surface of the container 110 facing the path of the light applied from the light source 122 to the photocurable resin 10 will be referred to as a light transmitting surface. In this case, the remaining surface of the container 110 excluding the light transmitting surface may be made of a material having light diffusing properties. So that the container 110 can provide only the light applied by the light source 122 to the photo-curing resin 10. The photo-curable resin 10 can be produced by mixing a base resin, a reactive diluent, a photopolymerization initiator, and the like as an example. At this time, an additive such as a photosensitizer, a colorant, a thickener, and a polymerization inhibitor may be added to the photocurable resin 10 depending on the use. As the base resin, ABS (Acrylonitrile Butadiene Styrene), PC (Polycarbonate), PP (Polypropylene) and the like can be used as an example. The base resin may be classified into polyester type, epoxy type, urethane type, polyether type, and polyacryl type depending on the structure of the molecular skeleton. As the photo-curable resin 10, for example, resin products produced by Makejuice, Madesolid, B9creater, Mud, etc. can be used

A projector 120 includes a light source 122 for selectively applying light to at least a portion of the photocurable resin 10 to cure the at least a part of the photocurable resin 10. In some other embodiments, the projector 120 may optionally further include a liquid crystal device 124 (see FIG. 2). In some other embodiments, the projector 120 may optionally further include a tunable optical filter 126 (see FIG. 2). In some other embodiments, the projector 120 may further include a projection lens system 128 optionally.

The light source 122 selectively applies light to at least a portion of the photocurable resin 10 to cure the at least a part of the photocurable resin 10. As the light source 122, various light sources such as infrared light, visible light, ultraviolet light, and white light having a wide wavelength band can be used. For example, when an infrared light source is used as the light source 122, the photo-curable resin 10 may be a photo-curing resin that reacts selectively with infrared rays to be cured. As another example, when a visible light source is used as the light source 122, the photo-curing resin 10 may be a photo-curing resin that reacts selectively with visible light to be cured. As another example, when an ultraviolet light source is used as the light source 122, the photo-curable resin 10 may be a photo-curable resin that selectively reacts with ultraviolet rays to be cured. As another example, a white light having a wide range of wavelength bands may be used as the light source 122. In this case, the user can select light having a desired wavelength band through the wavelength tunable optical filter 126 described later. On the other hand, a photoinitiator may be added to the photo-curing resin 10 to promote curing according to the wavelength of the provided light, or to induce curing.

The liquid crystal device 124 may be disposed on the optical path of the light provided by the light source 122 and may convert the light into image light and provide the light to at least a part of the photocurable resin 10. [ The image generated by the liquid crystal device 124 may be changed by the control unit 150. In addition, the intensity of the image light provided by the liquid crystal device 124 can be adjusted by the control unit 150. For example, the controller 150 may control the intensity of the image light by rotating the liquid crystal molecules included in the liquid crystal device 124 through the liquid crystal control signal 154. The time at which the photocurable resin 10 is cured may vary according to the intensity of the light applied to the photocurable resin 10. [ The intensity of the image light can be adjusted through the liquid crystal control signal 154 of the controller 150, and the curing time of the photocurable resin 10 can be controlled. In other words, the intensity of the image light can be adjusted through the liquid crystal control signal 154 of the controller 150, so that the exposure time of the image light applied to the at least a part of the photocurable resin 10 can be adjusted.

The image of the image light may correspond to any image data selected from a plurality of slice image data obtained by dividing the three-dimensional shape (1) into sectional layers. The plurality of slice image data may be stored in the database 140. The control unit 150 may extract the plurality of slice image data from the database 140. And image data sequentially arranged in the plurality of slice image data are referred to as first image data and second image data, respectively. The liquid crystal device 124 may generate a first image corresponding to the first image data under the control of the controller 150. [ In this case, the light provided by the light source 122 according to the first image generated by the liquid crystal device 124 is converted into the first image light corresponding to the first image. The converted first image light is supplied to the photocurable resin 10 during an exposure time which is controlled by the controller 150. Whereby a cured pattern corresponding to the first image light can be obtained. The build tray 20 moves according to the control of the control unit 150 and the pattern corresponding to the cured first image light moves along with the movement of the build tray 20. [ Subsequently, the liquid crystal device 124 may generate a second image corresponding to the second image data under the control of the control unit 150. In this case, the light provided by the light source 122 according to the second image generated by the liquid crystal device 124 is converted into the second image light corresponding to the second image. The converted second image light is supplied to the photocurable resin 10 during an exposure time which is controlled by the controller 150. Whereby a cured pattern corresponding to the second image light can be obtained. By repeating this, the desired three-dimensional shape (1) can be obtained. The build tray 20 referred to herein is disposed in a direction opposite to the light source 122 and means a portion of the build tray 20 where a part of the at least a part of the cured photocurable resin 10 is fixed.

The tunable optical filter 126 may be disposed on the optical path of the light provided by the light source 122 to change the wavelength of the light or the image light. In the figure, a tunable optical filter 126 disposed at the rear end of the liquid crystal device 124 based on the optical path of the light is shown as an example. In this case, the wavelength tunable optical filter 126 may change the wavelength of the image light changed by the liquid crystal device 124. [ As another example, unlike that shown in the figure, the tunable optical filter 126 may be disposed at the front end of the liquid crystal device 124 with respect to the optical path of the light. In this case, the tunable optical filter 126 may select the light of the desired wavelength range from the light provided by the light source 122 and provide the selected light to the liquid crystal device 124. The liquid crystal device 124 may then generate the image light from the light of the selected wavelength band. As the wavelength tunable optical filter 126, a filter or a prism filter that selectively selects various kinds of optical band pass filters can be used as an example. As an example for the sake of understanding, the above example is not limited to the kind of the wavelength variable optical filter 126 that can be disposed on the optical path of the light provided by the light source 122 and can change the wavelength of the light or the image light.

The wavelength tunable optical filter 126 is controlled by the wavelength control signal 156 of the control unit 150 so that the optical or liquid crystal device provided by the light source 122, The image light provided by the light source 124 may have a specific wavelength. The photo-curing resin 10 may be sensitive to light of a specific wavelength depending on the type. It is possible to generate a wavelength suitable for the above-mentioned kind of the photocurable resin 10 through the tunable optical filter 126.

The image light generated through the liquid crystal device 124 can be focused on the photo-curable resin 10 by the projection lens system 128. Alternatively, the wavelength-converted image light generated through the liquid crystal device 124 and the tunable optical filter 126 may be focused on the photocurable resin 10 by the projection lens system 128. [

The sensor 130 is disposed adjacent to the projector 120 and measures any one of light intensity, wavelength, and combination of light that the light source 122 applies to at least a part of the photocurable resin 10. The sensor 130 may be, for example, a spectroscope. The intensity of the light measured by the sensor 130, the wavelength, and a combination thereof are provided to the controller 150.

The database DB 140 stores the exposure time of light applied to the photo-curable resin 10 for curing the photo-curable resin 10 for each type of photo-curable resin 10. [ For example, the database 140 may store the exposure time so as to correspond to any one of the light intensity, the wavelength of the light, and a combination thereof depending on the type of the photo-curable resin 10. Meanwhile, the database 140 may include a plurality of slice image data obtained by dividing the three-dimensional shape 1 into sectional layers. The three-dimensional shape (1) is a three-dimensional shape obtained through a three-dimensional printer disclosed in this specification, and the three-dimensional shape can be obtained through exposure after extracting slice image data sequentially from the plurality of slice image data.

The above example shows the structure of the database 140 with respect to the exposure time t as an example. The control unit 150 receives any one of the intensity of the light measured from the sensor 130, the wavelength and combinations thereof, and extracts the exposure time t corresponding to the value received from the database 140 And the light generated in the projector 120 may be applied to the photocurable resin 10 during the extracted exposure time t.

The above example shows the structure of the database 140 for the liquid crystal control signal (C, 154) as an example. The control unit 150 may receive the slice image data from the plurality of slice image data stored in the database 140 according to the exposure sequence and may generate the liquid crystal control signal 154 from the received slice image data. In the above example, as slice image data stored in the database 140, slice image data including a liquid crystal control signal (C, 154) is shown as an example. As another example, unlike the one shown in the figure, the plurality of slice image data stored in the database 140 may include a shade value. The range of the shading value may be, for example, from 0 to 255. [ In this case, the control unit 150 may generate the liquid crystal control signal 154 from the shade value and control the liquid crystal device 124 to display the slice image.

The control unit 150 extracts from the database 140 the exposure time corresponding to any one of the intensity and wavelength of the light measured by the sensor 130 and a combination thereof, So that the light is applied to at least a part of the photocurable resin 10 during the exposure time. The input instruction of the user may be input through the touch screen 30, for example, as shown in the figure. The above example is an example for the sake of understanding, and the input instruction of the user may be inputted through another input means such as a keyboard (not shown). The touch screen 30 may display any one of the intensity of the light measured by the sensor 130, the wavelength, and a combination thereof. In addition, the touch screen 30 may display a three-dimensional shape 1 obtained through exposure, a slice image corresponding to an ongoing exposure process, an intermediate shape of the three-dimensional shape 1 advanced through exposure so far, and the like have.

In one embodiment, the projector 120 is disposed on the optical path of the light provided by the light source 122 via the liquid crystal device 124 and converts the light into image light, It can be provided to some. Whereby the light provided by the light source 122 can be converted into the image light and provided to the at least a part of the photocurable resin 10. [ In other words, the control unit 150 may receive the slice image data corresponding to the image of the image light from the plurality of slice image data of the database 140. [ The control unit 150 then generates a liquid crystal control signal 154 from the received slice image data and applies the generated liquid crystal control signal 154 to the liquid crystal device 124 so that the liquid crystal device 124 The image can be displayed. Whereby the light generated by the light source 122 can be converted into the image light and provided to the at least a part of the photocurable resin 10. [ In this case, the sensor 130 may measure the intensity and the wavelength of the image light. The control unit 150 can extract the intensity of the image light measured by the sensor 130 and the exposure time corresponding to the wavelength from the database 140. [ Based on the extracted exposure time, the control unit 140 controls the liquid crystal device 124 so that the image of the image light displayed by the liquid crystal device 124 is the exposure time of the image light extracted from the database 140 Lt; / RTI > Accordingly, the three-dimensional printer 100 disclosed in this specification can automatically select an appropriate exposure time even if the intensity and the wavelength of the light provided by the light source 122 change according to the frequent use of the light source 122 It is possible to stably ensure the accuracy or quality of the output.

On the other hand, the liquid crystal device 124 includes a liquid crystal layer (not shown) having liquid crystal molecules. In this case, the control unit 150 can adjust the intensity of the image light by rotating the liquid crystal molecules disposed in the liquid crystal layer through the liquid crystal control signal 154 applied to the liquid crystal device 124. The intensity and wavelength of the image light adjusted by rotating the liquid crystal molecules can be measured through the sensor 130. Thereafter, the controller 150 may extract the intensity of the adjusted image light and the exposure time corresponding to the wavelength from the database 140. On the basis of the extracted exposure time, the control unit 140 controls the liquid crystal device 124 to perform the exposure of the adjusted image light from which the image of the adjusted image light displayed by the liquid crystal device 124 is extracted And can be controlled to be maintained for a period of time. Accordingly, the three-dimensional printer 100 disclosed in this specification can control the intensity of the image light provided to the photocurable resin 10 through the rotation of the liquid crystal molecules through the controller 150. That is, without changing the light source 122, the image light having various intensities can be generated only by the control unit 150 by adjusting the liquid crystal device 124, thereby ensuring the accuracy or quality of the output stably.

In another embodiment, the projector 120 converts the light into image light through a liquid crystal device 124 disposed on the optical path of the light provided by the light source 122, It can be provided to some. In this case, the projector 120 can change the wavelength of the light or the image light through the wavelength variable optical filter 126 disposed on the optical path of the light provided by the light source 122. That is, the light provided by the light source 122 can be converted to the wavelength-converted image light via the liquid crystal device 124 and the tunable optical filter 126 and provided to the at least part of the photocurable resin 10 . The sensor 130 may measure the intensity and the wavelength of the wavelength-converted image light. The control unit 150 can extract the intensity of the wavelength-converted image light and the exposure time corresponding to the wavelength from the database 140. [ Based on the extracted exposure time, the controller 150 controls the liquid crystal device 124 and the tunable optical filter 126 so that the wavelength-converted image light is extracted for the exposure time of the wavelength- Can be controlled. Accordingly, the three-dimensional printer 100 disclosed in this specification can automatically select an appropriate exposure time even if the intensity and the wavelength of the light provided by the light source 122 change according to the frequent use of the light source 122 It is possible to stably ensure the accuracy or quality of the output.

On the other hand, the liquid crystal device 124 includes a liquid crystal layer (not shown) having liquid crystal molecules. In this case, the control unit 150 can adjust the intensity of the wavelength-converted image light by rotating the liquid crystal molecules disposed in the liquid crystal layer through the liquid crystal control signal 154 applied to the liquid crystal device 124. In addition, the control unit 150 may control the wavelength tunable optical filter 126 to adjust the wavelength-converted image light to have a predetermined wavelength. The intensity and the wavelength of the wavelength-converted image light modulated by the control unit 150 can be measured by the sensor 130. [ Thereafter, the controller 150 may extract the intensity of the adjusted wavelength-converted image light and the exposure time corresponding to the wavelength from the database 140. Based on the extracted exposure time, the controller 150 controls the liquid crystal device 124 and the tunable optical filter 126 so that the image of the adjusted wavelength-converted image light displayed by the liquid crystal device 124 Converted image light extracted at the predetermined wavelength during the exposure time of the wavelength-converted image light.

Generally, the photocurable resin 10 exhibits a tendency to react at a specific wavelength band for each type. Therefore, when the wavelength of the light provided by the light source 122 changes according to frequent use of the light source 122, it is difficult to obtain a desired precise pattern only by adjusting the light intensity or adjusting the exposure time of the light. The three-dimensional printer 100 disclosed in this specification includes a tunable optical filter 126. Accordingly, the three-dimensional printer 100 disclosed in the present specification can provide image light having an appropriate wavelength for each type of the photocurable resin 10 through the wavelength tunable optical filter 126, that is, the wavelength-converted image light. In other words, the three-dimensional printer 100 disclosed in this specification can provide light of a wavelength suitable for the photocurable resin 10 used from the control of the tunable optical filter 126 through the control unit 150. [ In addition, the intensity of the wavelength-converted image light provided to the photocurable resin 10 through rotation of the liquid crystal molecules through the control unit 150 may be adjusted. That is, the wavelength-converted image light having various wavelengths and intensities can be generated by only the adjustment of the liquid crystal device 124 and the tunable optical filter 126 by the control unit 150 without changing the light source 122, Or quality can be stably ensured.

From the foregoing it will be appreciated that various embodiments of the present disclosure have been described for purposes of illustration and that there are many possible variations without departing from the scope and spirit of this disclosure. And that the various embodiments disclosed are not to be construed as limiting the scope of the disclosed subject matter, but true ideas and scope will be set forth in the following claims.

10: Photocurable resin
20: Build Tray
30: Touch screen
100: 3D printer with automatic exposure control function
110: container
120: Projector
122: Light source
124: liquid crystal device
126: wavelength tunable optical filter
128: projection lens system
130: sensor
140: Database
150:
154: liquid crystal control signal
156: Wavelength control signal

Claims (5)

A container in which a photocurable resin is disposed;
A projector that includes a light source that selectively applies light to at least a portion of the photocurable resin to cure the at least a portion of the photocurable resin;
A sensor disposed adjacent to the projector and measuring at least one selected from the light intensity, wavelength, and combinations thereof, the light source applying to the at least a part of the photocurable resin;
A database for storing the exposure time of the light applied to the photo-curing resin for curing the photo-curing resin for each kind of the photo-curing resin; And
Extracting, from the database, the exposure time corresponding to any one of the intensity, the wavelength, and the combination of the light measured by the sensor, and controlling the projector according to a user's input command or a preset program, And a control unit for causing light to be applied to the at least a part of the photocurable resin during the exposure time,
Wherein the database stores the exposure time so as to correspond to any one of the intensity of the light, the wavelength of the light, and a combination thereof according to the type of the photocurable resin. The method according to claim 1,
The database includes a plurality of slice image data obtained by dividing a three-dimensional shape into cross-sectional layers,
The projector comprising a liquid crystal device disposed on an optical path of the light provided by the light source to convert the light into image light to provide to at least a portion of the photocurable resin,
Wherein the control unit receives slice image data corresponding to an image of the image light from the plurality of slice image data of the database, generates a liquid crystal control signal from the received slice image data, The liquid crystal device being adapted to display the image of the image light on the liquid crystal device so that the light is converted into the image light and provided to the at least a portion of the photo-
The sensor measures intensity and wavelength of the image light,
Wherein the controller extracts the intensity of the image light and the exposure time corresponding to the wavelength from the database,
Wherein the controller controls the liquid crystal device so that the image of the image light displayed by the liquid crystal device is retained for the exposure time of the extracted image light. 3. The method of claim 2,
Wherein the liquid crystal device includes a liquid crystal layer having liquid crystal molecules,
Wherein the controller controls the intensity of the image light by rotating the liquid crystal molecules disposed in the liquid crystal layer through the liquid crystal control signal applied to the liquid crystal device,
Wherein the sensor measures the intensity and the wavelength of the image light modulated by the control unit,
Wherein the control unit extracts, from the database, the intensity of the adjusted image light and the exposure time corresponding to the wavelength,
Wherein the control unit controls the liquid crystal device so that the image of the adjusted image light displayed by the liquid crystal device is held for the exposure time of the adjusted image light extracted. 3. The method of claim 2,
Wherein the projector comprises a wavelength variable optical filter disposed on an optical path of the light provided by the light source to change the wavelength of the light or the image light,
Wherein the light provided by the light source is converted into wavelength converted image light via the liquid crystal device and the wavelength tunable optical filter and is provided to the at least a part of the photocurable resin,
The sensor measures intensity and wavelength of the wavelength-converted image light,
Wherein the controller extracts the intensity of the wavelength-converted image light and the exposure time corresponding to the wavelength from the database,
Wherein the controller controls the liquid crystal device and the wavelength tunable optical filter to maintain the wavelength converted image light extracted for the exposure time. 5. The method of claim 4,
Wherein the liquid crystal device includes a liquid crystal layer having liquid crystal molecules,
Wherein the controller controls the intensity of the wavelength-converted image light by rotating the liquid crystal molecules disposed in the liquid crystal layer through the liquid crystal control signal applied to the liquid crystal device,
Wherein the controller controls the wavelength tunable optical filter so that the wavelength-converted image light has a predetermined wavelength,
Wherein the sensor measures the intensity and the wavelength of the wavelength-converted image light modulated by the controller,
Wherein the control unit extracts, from the database, the intensity of the adjusted wavelength-converted image light and the exposure time corresponding to the wavelength,
Wherein the controller controls the liquid crystal device and the wavelength tunable optical filter so that the image of the adjusted wavelength-converted image light displayed by the liquid crystal device displays the exposure time of the adjusted wavelength-converted image light extracted at the predetermined wavelength Dimensional printer having an automatic exposure control function.

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