Upscaling of print volume using multiple projectors in tomographic volumetric 3D printing

Abstract

This disclosure relates to a method for manufacturing a three-dimensional object, the method comprising: calculating a plurality of subsinograms, the subsinograms being derived from at least one sinogram describing a three-dimensional object formed from different orientation angles; providing a build volume containing a photosensitive component capable of initiating a photochemical reaction upon irradiation with light of an activation wavelength; and irradiating the build volume at a corresponding orientation angle using a series of light projections corresponding to one of the subsinograms, each of a plurality of projection units, wherein the irradiating light includes an activation wavelength; each projection unit irradiates the build volume with a series of light patterns derived from different subsinograms, and as a result, the build volume is irradiated with a series of light patterns resulting from the corresponding sinogram at the corresponding orientation angle.

Description

Technical Field

[0001] The present disclosure relates to a system and method for tomographic bath photopolymerization for 3D printing of an object with improved resolution including spatial resolution (horizontal and / or vertical) and / or temporal resolution by a plurality of projection units arranged to irradiate a shaping volume.

Background Art

[0002] Additive manufacturing (AM) techniques are technologies for manufacturing a wide range of structures and complex geometries based on three-dimensional model data. This process relies on successive layers of material printed on top of each other. This technology was originally developed in a process known as stereolithography (SLA).

[0003] SLA typically uses UV light to initiate a chain reaction on a layer of a resin or monomer solution, such as an acrylic or epoxy-based one. The monomers are UV-active and are converted into polymer chains after activation (radicalization). Through polymerization, a pattern is created within the resin layer, and when the resin layer solidifies, subsequent layers can be held in place. After printing, the unreacted resin is removed. Further, depending on the material and desired mechanical properties, post-processing such as heating or photocuring can be applied to the printed object.

[0004] SLA is a highly versatile method and is widely used mainly due to its success in rapid and inexpensive prototyping, but it has the drawback of slow printing speed. This characteristic is inherent to SLA because it is a layer-by-layer processing method. When a layer is irradiated and cured, depending on the shaping direction, a new layer of uncured material needs to be provided either above or below the solid layer. Most commonly, the uncured material is provided by mechanically recoating the surface, which not only increases the printing time but may also act to distort the shaped object.

[0005] Another, more recent technique is tomography vat photopolymerization (TVP), in which the build volume containing the photosensitive component is illuminated from multiple angles to rapidly produce complex materials. Thus, this technique relies on a completely different approach compared to layer-by-layer techniques, as it physically reverses the principle of computed tomography (CT) to achieve high-speed, auxiliary-free 3D printing.

[0006] WO2018 / 208378 discloses a method for forming an object, comprising providing a volume of photocurable resin contained within an optically transparent resin container and simultaneously directing light projections from multiple angles around the z-axis extending through the volume of photocurable resin. The projections act over a fixed temporal exposure period, during which the net exposure is sufficient to cure a selected portion of the volume of photocurable resin while leaving the other portions uncured.

[0007] Photopolymerization of tomography vats is still in its early stages and holds great potential. However, a significant drawback is the limited resolution that can be achieved, making it difficult to realize, for example, three-dimensional objects with small features or sharp angles. [Overview of the project]

[0008] The inventors have recognized that the technical field of tomography vat polymerization (TVP) is built upon knowledge derived from computed tomography (CT), in that tomography vat polymerization physically reverses the principles of CT, but that tomography vat polymerization is limited by the projection units currently available, which acts to limit the resolution of the three-dimensional object formed by tomography vat photopolymerization. Furthermore, the inventors have recognized that multiple projection units can be combined in such a way that the resolutions provided by each individual projection unit (e.g., spatial resolution and / or temporal resolution) can be combined to improve the maximum achievable resolution.

[0009] Therefore, in the first aspect, the present disclosure relates to a method for manufacturing a three-dimensional object, and this method is The calculation involves computing multiple sets of subsinograms, where each set of subsinograms is derived from a set of sinograms, and each sinogram describes layers of a three-dimensional object formed from different orientation angles. To provide a build volume containing a photosensitive component that can initiate a photochemical reaction when irradiated with light of an activation wavelength, The process includes irradiating the build volume with light containing the activation wavelength at the corresponding orientation angle, using a series of light projections corresponding to one of the sets of subsinograms, each of multiple projection units, Each projection unit illuminates the build volume with a series of light patterns derived from different sets of subsinograms, and as a result, the build volume as a whole is illuminated with a series of light patterns corresponding to the set of sinograms at the corresponding orientation angles.

[0010] Typically, the illumination resulting from the build volume has a resolution higher than the maximum resolution of any of the individual projection units. The improvement in resolution may be, for example, an improvement in spatial resolution (e.g., horizontal and / or vertical), and additionally or alternatively, the improvement in resolution may be an improvement in temporal resolution.

[0011] Another effect of the currently disclosed method is that three-dimensional objects can be manufactured more quickly because the build volume is irradiated with power equal to the sum of the contributions of each projection unit.

[0012] Therefore, in order to overcome the resolution limitations associated with conventional tomography vat polymerization, the inventors recognized that a sinogram can be divided into subsinograms, and as a result, a three-dimensional object can be manufactured by irradiating the photosensitive component with multiple orientation angles and light patterns from projection units, with each subsinogram having an associated projection unit. Thus, each subsinogram can be associated with a different projection unit.

[0013] As a result, a three-dimensional object can be physically reproduced with a resolution (e.g., spatially and / or temporally) higher than the maximum resolution of any of the individual projection units.

[0014] Therefore, each projection unit is typically arranged to illuminate the build volume with a series of light patterns at corresponding angles, typically with light of the same wavelength, preferably simultaneously or at least partially simultaneously (so that the illuminations overlap in time), and the pattern of each projection unit corresponds to the subsinogram of a particular projection unit. The resulting illumination of the build volume typically corresponds to what would only be achievable by a projection unit having a higher resolution than any of the individual projection units.

[0015] In this way, the resolution of a sinogram and / or object will not be limited by the number of pixels in a single projection unit. Typically, the resolution limit will instead be limited by the chemical reaction of the photosensitive components and / or the diffraction limit of the optical system used to generate a series of light patterns.

[0016] In a general sense, the disclosure is not limited to a specific number of projection units, and therefore, the disclosure may enable resolution enhancement by combining the resolutions provided by any number of projection units, for example, by virtually stitching subsinograms to maximize the number of pixels they can provide for illumination resulting from the sinogram and / or build volume.

[0017] In a further aspect, the disclosure relates to a method for manufacturing a three-dimensional object, the method being: • Computing a set of sinograms that describe three-dimensional objects formed from different orientation angles, To provide a build volume containing a photosensitive component that can initiate a photochemical reaction when irradiated with light of an activation wavelength, Illuminating a build volume using a series of light projections by each of a plurality of projection units, such that the build volume is illuminated with a series of light patterns resulting from a set of sinograms at corresponding orientation angles, the illumination light includes an activation wavelength, the projection units have one or more depths of field shorter than the distance of the three-dimensional object, for example along the optical axis, and the focal plane of each projection unit is selected such that the resulting combined depth of field of all projection units spans the distance of the three-dimensional object, for example along the optical axis.

[0018] In a further aspect, the disclosure relates to a method for manufacturing a three-dimensional object, the method being: • Computing a set of sinograms that describe three-dimensional objects formed from different orientation angles, To provide a build volume containing a photosensitive component that can initiate a photochemical reaction when irradiated with light of an activation wavelength, The process involves irradiating the build volume at a corresponding orientation angle using a series of light projections corresponding to a set of sinograms, each of a plurality of projection units having the same refresh rate f, wherein the irradiated light includes an activation wavelength, and at least one of the projection units is positioned to irradiate the build volume with projections at a corresponding orientation angle with a delay given by 1 / (f·n) relative to the other projection units, where n is a natural number.

[0019] In this way, the temporal resolution can be improved. Typically, n is the number of projection units used to illuminate the build volume with a series of light patterns. A projection unit is, for example,

number

[0020] Therefore, one of these projection units may have a delay of 0, while each of the other projection units has a delay that increases by 1 / (fn) for each projection unit.

[0021] In a further aspect, the present disclosure relates to a method for manufacturing a three-dimensional object, the method comprising: · calculating a set of sinograms describing a three-dimensional object formed from different orientation angles; · providing a build volume comprising a photosensitive component capable of initiating a photochemical reaction upon irradiation with light of an activation wavelength; · irradiating the build volume with a series of patterns of light corresponding to the set of sinograms at corresponding orientation angles by each of a plurality of projection units, the irradiation light including the activation wavelength.

[0022] Therefore, each projection unit can be arranged to illuminate the build volume with a series of patterns of light corresponding to the sinogram. However, the use of multiple projectors can result in a faster manufacturing time, for example, because the power applied to the build volume during the irradiation step is equal to the sum of the contributions of each projection unit. The projection units do not need to be synchronized and may have different refresh rates, but may be arranged to start and / or stop irradiating the build volume simultaneously.

[0023] In a further aspect, the present disclosure relates to a system for manufacturing a three-dimensional object, the system comprising: · a processing unit configured to calculate a set of multiple sub-sinograms, each set of sub-sinograms being derived from the set of sinograms, each sinogram describing a layer of a three-dimensional object formed from different orientation angles; · a build volume comprising a photosensitive component capable of a photochemical reaction upon irradiation with light of an activation wavelength; · a projection system comprising a plurality of projection units capable of irradiating the build volume with a series of patterns of light including this activation wavelength. • A direction adjustment unit for controlling and varying the direction of light incidence of the projection unit relative to this build volume, The system comprises a controller configured to control the orientation unit and projection system so that the build volume is illuminated with light containing the activation wavelength at a corresponding orientation angle, using a series of light projection patterns corresponding to one of a set of subsinograms, each of which is projected by multiple projection units, Each projection unit illuminates the build volume with a series of light patterns derived from different sets of subsinograms, and as a result, the build volume as a whole is illuminated with a series of light patterns corresponding to the set of sinograms at the corresponding orientation angles.

[0024] In a further aspect, the present disclosure relates to a system for manufacturing a three-dimensional object, the system is A processing unit configured to compute a set of sinograms describing three-dimensional objects formed from different orientation angles, • A build volume containing a photosensitive component capable of undergoing a photochemical reaction when irradiated with light containing an activation wavelength, A projection system comprising multiple projection units having the same refresh rate and capable of irradiating the build volume with a series of light patterns including the activation wavelength, • A direction adjustment unit for controlling and varying the direction of light incidence of the projection unit relative to this build volume, A controller configured to control a directional adjustment unit and a projection system so that the build volume is illuminated at a corresponding orientation angle using a series of light projections corresponding to a set of sinograms, wherein the illumination light includes an activation wavelength, and at least one of the projection units is positioned to illuminate the build volume with projection at a corresponding orientation angle with a delay given by 1 / (f·n) relative to the other projection units, where n is a natural number.

[0025] In a further aspect, the present disclosure relates to a system for manufacturing a three-dimensional object, the system is A processing unit configured to compute a set of sinograms describing three-dimensional objects formed from different orientation angles, • A build volume containing a photosensitive component capable of undergoing a photochemical reaction when irradiated with light containing an activation wavelength, A projection system comprising multiple projection units capable of irradiating the build volume with a series of light patterns including activation wavelengths, • A direction adjustment unit for controlling and varying the direction of light incidence of the projection unit relative to this build volume, A controller configured to control a directional adjustment unit and a projection system so that the build volume is illuminated using a series of light projections corresponding to a set of sinograms at corresponding orientation angles, wherein the illuminated light includes an activation wavelength.

[0026] Typically, the build volume is illuminated at a resolution higher than the maximum resolution of any one of the individual projection units. A further possible effect is that three-dimensional objects can be manufactured more quickly because the build volume is illuminated with power equal to the sum of the contributions of each projection unit.

[0027] The improvement in resolution may be, for example, an improvement in spatial resolution (e.g., horizontal and / or vertical), and additionally or alternatively, the improvement in resolution may be an improvement in temporal resolution.

[0028] The system of this disclosure is preferably configured to perform a method for manufacturing a three-dimensional object, as disclosed elsewhere in this specification.

[0029] Advantageously, the methods disclosed herein enable improved resolution of tomographic vat photopolymerization, for example, one or more of the horizontal resolution, vertical resolution, and / or temporal resolution, and the resolution of the sinogram describing a three-dimensional object formed from multiple orientation angles.

[0030] Improving horizontal and vertical resolution relies on the use of multiple projection units, thereby dividing the sinogram among different projection units to reach the maximum number of pixels acceptable in that particular setup. Horizontal and vertical resolution can be improved simultaneously, i.e., virtual stitching is performed in both the horizontal and vertical planes.

[0031] Furthermore, temporal resolution can be improved by synchronizing the projections of multiple projection units. This is achieved by having multiple projection units with overlapping virtual alignments of projection areas. A single projector has a finite temporal resolution, e.g., 60 Hz, but the temporal resolution of multiple projection units is given by 1 / (f·n), where f is the refresh rate and n is the number of projection units.

[0032] Therefore, the illumination can be arranged so that the build volume is illuminated with a time resolution higher than any of the time resolutions (i.e., refresh rates) of the individual projection units, and / or with a time resolution up to the sum of the maximum refresh rates of all projection units. Thus, each projection unit is arranged in its corresponding orientation to illuminate the build volume with a series of light patterns corresponding to one individual sub-sinogram, so that the build volume is illuminated with a series of light patterns corresponding to the sinogram.

[0033] This approach reduces printing time by using a virtual alignment of overlapping projection areas from multiple projection units, thereby increasing power output (e.g., Mw / cm²). 2 This allows for improvements in performance. However, synchronization is not necessary to increase power output to reduce printing time.

[0034] In the following embodiments, examples will be described in more detail with reference to the attached drawings. [Brief explanation of the drawing]

[0035] [Figure 1]A schematic diagram of a system comprising multiple projection units according to an embodiment of the present disclosure is shown. [Figure 2] Embodiments of this disclosure show, for example, a sinogram and virtual alignment of a projection region for improving horizontal resolution. [Figure 3] Figure 2A shows a sinogram divided into multiple subsinograms according to a radial index according to an embodiment of the present disclosure, where the angular index of the subsinograms is shifted to compensate for the relative orientation of different projection units. [Figure 4] This embodiment of the disclosure shows virtual alignment for improving horizontal and vertical resolution compared to a single projection unit. [Figure 5] This embodiment of the disclosure demonstrates the increase in output power achieved by using multiple projection units. [Figure 6] A schematic diagram of a system for improving temporal resolution by synchronizing multiple projection units, according to an embodiment of this disclosure, is shown. [Figure 7] A flowchart outlining a method for manufacturing a multi-material three-dimensional object according to a specific embodiment of this disclosure is shown. [Figure 8] A flowchart outlining a method for manufacturing a multi-material three-dimensional object according to a specific embodiment of this disclosure is shown. [Figure 9] A flowchart outlining a method for manufacturing a multi-material three-dimensional object according to a specific embodiment of this disclosure is shown. [Figure 10] This disclosure describes a tomography vat photopolymerization system for manufacturing a three-dimensional object from a build volume, according to a specific embodiment of this disclosure. [Figure 11] An example of the system of this disclosure, which includes multiple projection units, is shown, where the focal plane of each projection unit is shifted relative to the center of the build volume. [Figure 12] Figure 11 shows a schematic diagram of the resulting virtual alignment at the focal plane, where multiple projection units have a combined depth of field across the workpiece. [Figure 13] The present disclosure shows a system comprising multiple projection units and a schematic diagram of a sinogram divided into subsinograms by an angular index, according to an embodiment of this disclosure. [Modes for carrying out the invention]

[0036] As used herein, unless otherwise clearly indicated by the context, the singular forms preceded by "a," "an," and "the" include multiple references.

[0037] The term "several embodiments" may include one or more embodiments.

[0038] As used herein, “multiple” means at least two. However, in many cases, at least four, sometimes at least ten, or even an infinite number of projection units are used.

[0039] In a first aspect, the disclosure relates to a method for manufacturing three-dimensional objects.

[0040] sinogram In CT and SPECT imaging, a sinogram is generated by rotating a detector around the patient and storing the detected projection profile at each angle in the sinogram. Tomographic vat polymerization can be said to reverse this process, in that a series of light patterns corresponding to the sinogram are projected onto the build volume to form a three-dimensional object. However, the sinogram may be modified to more accurately fabricate the three-dimensional object, and this can also be done in CT / SPECT imaging when back projection is performed to accurately reconstruct the three-dimensional object. For example, the sinogram may be modified to include negative intensity values ​​to more accurately reproduce the three-dimensional object.

[0041] To describe a three-dimensional object formed from multiple orientation angles, a set of sinograms / subsinograms is typically required, because each individual sinogram typically describes only a single layer of the object from multiple orientation angles. The height of each layer described by the sinogram typically corresponds to the height of the voxels in the build volume. Therefore, the thickness of the layer described by the sinogram is typically the thickness of the voxels in that layer and is typically perpendicular to the orientation angles of the sinogram. Typically, the sinogram describes the object in a horizontal plane. Rotation of the build volume (and / or projection unit) is performed on an axis of rotation that is typically perpendicular to the plane on which the sinogram describes the object. Therefore, typically, the sinogram describes the object from multiple orientation angles in a horizontal plane, the axis of rotation is perpendicular, and typically passes through the center of the build volume.

[0042] As used herein, virtual alignment refers to the use of multiple projection units to create a high-resolution light pattern resulting from a set of sinograms, by using multiple projection units, each to which a set of sinograms is assigned. A set of sinograms corresponds to a series of light patterns from multiple orientation angles necessary for manufacturing a three-dimensional object. As an example, consider only the light pattern corresponding to a single angular index of the set of sinograms. This pattern can be created by aligning the light patterns of multiple projection units. Since different projection units have different orientation angles relative to the build volume, the timing of the different projection units is shifted, and therefore the light patterns can be said to be virtually aligned.

[0043] To overcome the resolution limitations associated with tomography vat polymerization, one or more sinograms can be divided into subsinograms, and as a result, a three-dimensional object can be manufactured by irradiating the photosensitive component with light patterns from multiple angles and projection units.

[0044] A two-dimensional object may be described by a sinogram, while a three-dimensional object may be described by a set of sinograms. For example, each layer of a three-dimensional object may be represented by a different sinogram from the set of sinograms. Furthermore, a sinogram may be divided into two or more subsinograms. Similarly, a set of sinograms may be divided into two or more sets of subsinograms. In a particular example, a set of sinograms may be used to describe a three-dimensional object formed from a corresponding orientation angle. This set of sinograms may be divided into two or more sets of subsinograms that together describe the three-dimensional object formed from the corresponding orientation angle. Each set of subsinograms may, for example, describe a different spatial or temporal part of the three-dimensional object being formed. Furthermore, a set of subsinograms may be used to change the depth of field, as described herein.

[0045] Typically, projection units are arranged to illuminate the build volume (i.e., the photosensitive components of the build volume) at least partially simultaneously, for example, so that at least some of the illuminations from multiple projections overlap in time. It is also preferable that each sinogram be associated with a single wavelength, or at least a narrow spectral band, typically the wavelength / band to which the photosensitive components are sensitive, e.g., a wavelength / band to which polymerization of monomers in the build volume can be formed. Therefore, the series of patterns of light used to illuminate the build volume should be at this particular wavelength(s). In specific examples of this disclosure, multiple sinograms are used to represent a three-dimensional volume. In such cases, each sinogram may be associated with a distinct wavelength(s), each wavelength selected to activate a distinct photosensitive compound in the build volume. Thus, in such cases, the build volume may contain multiple different photosensitive materials / components, for example, used to produce three-dimensional objects of different materials, as disclosed in WO2022 / 090318. However, in this disclosure, each sinogram is used to derive multiple subsinograms, and each subsinogram is associated with a separate projection unit as disclosed herein.

[0046] A sinogram contains an arbitrary two-dimensional array of numbers where one index is radial (i.e., radial index, (16) in Figure 2A) and the other index is angular (i.e., angular index, (17) in Figure 2A).

[0047] Typically, each line of a sinogram, i.e., the same angular index, may contain values ​​such as intensity values ​​that can vary according to the radial index. Therefore, a sinogram may, for example, determine the pixel values ​​of a projection unit for a single line of pixels.

[0048] Furthermore, a set of sinograms may be used, each sinogram in the set having a different vertical index. The series of patterned lights irradiated by the projection unit can be provided by irradiating the build volume with patterned lights given by radial, angular, and vertical index values. That is, the radial index may describe intensity values ​​along a plane such as a horizontal plane, and the vertical index may describe intensity values ​​along another plane such as a vertical plane. That is, the radial and vertical indices may correspond to the x and y axes of the patterned light. The angular index represents the corresponding orientation angle between the projection unit and the plane of the build volume.

[0049] When the build volume rotates relative to the projection unit, the light of each pattern in a series of light patterns can be given by a different angular index. Therefore, in other embodiments, when the build volume does not rotate relative to the projection unit, for example, in the case of multiple fixed projection units, such as one or more digital micromirror devices, the relative orientation angle between the projection unit and the build volume determines the light pattern that is projected onto the build volume by this projection unit. Thus, the orientation angle is associated with the angular index of the sinogram.

[0050] Therefore, in one example, the intensity value at a specific angular index of each sinogram in a set of sinograms may determine the intensity value along the first axis of the pattern of light illuminating the build volume. Different sinograms in the set can be used to create a projection, since each sinogram may correspond to a single line of this projection. Thus, each value in the set of sinograms may be assigned a radial index, an angular index, and a vertical index, and each sinogram in this set may have a different vertical index.

[0051] Furthermore, as disclosed elsewhere in this specification, each sinogram in this set of sinograms may be divided by their radial index and assigned to different projection units. In this way, each projection unit may be positioned to illuminate only a portion of the build volume (e.g., a portion of the workpiece). The angular index of each set of sub-sinograms is typically shifted to compensate for different relative orientation angles of the projection units, for example, when they are positioned in different orientations with respect to the build volume.

[0052] Examples of sinograms include sets of projections, sets of radially filtered projections, and sets of radially inverse Fourier transformed synthetic aperture radar (SAR) data.

[0053] In one embodiment of the present disclosure, the method disclosed herein includes the step of calculating several subsinograms describing a three-dimensional object formed from different orientation angles of the object. The method may include, for example, calculating a sinogram and then generating subsinograms.

[0054] A subsinogram may be derived, for example, by subdividing a sinogram into multiple subsinograms that describe the sinogram of the object formed by multiple projection units. Thus, a subsinogram may be a part of a sinogram, which is modified by an angular shift to compensate for the position of the projection units relative to the build volume. Therefore, the number of subsinograms may be a multiple of the number of sinograms.

[0055] A subsinogram may be used to illuminate the build volume with a series of patterned lights. In some embodiments, the projection of a projection unit is arranged such that each horizontal line of pixels corresponds to one pattern (i.e., of the corresponding orientation angle) of a subsinogram. However, the projection may include one such pattern for each horizontal line, and therefore each projection unit may be arranged to illuminate the build volume with multiple patterned lights, each based on a subsinogram associated with a particular projection unit. Thus, typically, a projection unit has a number of horizontal pixels (i.e., the horizontal resolution of the projection unit) used to illuminate the build volume with a series of patterned lights based on a subsinogram at the corresponding orientation angle. Furthermore, the projection unit typically has a number of vertical pixels (i.e., defined by the vertical resolution of the projection unit). Each horizontal row may be assigned, as described above, to illuminate the build volume with a series of patterned lights corresponding to a subsinogram at the corresponding orientation angle.

[0056] In some embodiments of this disclosure, the sinogram is calculated using one of the following lists: a tomography reconstruction filter after a radon transform, a tomography reconstruction filter after a fan beam algorithm, and / or a tomography reconstruction filter after a cone beam algorithm. The sinogram may be formed, for example, by applying a radon transform accompanied by a tomography reconstruction filter. The resulting projection may be a two-dimensional pattern, each having a corresponding orientation angle. Irradiation of the build volume can be performed by using multiple projection units, with multiple projection units irradiating the build volume from different angles, or a single light source may be used. However, it is preferable that the light pattern irradiates the build volume with a similar wavelength distribution.

[0057] In some embodiments of the present disclosure, the sinogram is computed, at least in part, by using one of the following projection algorithms: Radon transform, fan beam algorithm, cone beam algorithm, tomography reconstruction filter, iterative reconstruction technique, algebraic reconstruction technique, and / or diffraction tomography algorithm, or a combination thereof.

[0058] As a result, the calculation may include the application of a tomography reconstruction filter after a Radon transform, a tomography reconstruction filter after a fan beam algorithm, a tomography reconstruction filter after a cone beam algorithm, an iterative reconstruction technique, an algebraic reconstruction technique, or a diffraction tomography algorithm, or a combination thereof. In one embodiment of the present disclosure, a sinogram is obtained by applying at least one projection algorithm to a computer-based model. Thus, this method can be considered a method for manufacturing a three-dimensional object that is a reproduction of this computer-based model. In one embodiment of the present disclosure, the method is a computer implementation method or a processor implementation method.

[0059] In some embodiments of the present disclosure, a sinogram is divided into subsinograms. Typically, each subsinogram has the number of pixels of the associated projection unit (a projection unit used to illuminate the build volume with a set of light patterns corresponding to this particular subsinogram) and a similar or equivalent number of pixels in the same axial direction, and typically in the same axial direction.

[0060] In some embodiments of this disclosure, all projection units are arranged to begin illuminating the build volume simultaneously. Typically, each projection unit is arranged to illuminate the build volume in a different orientation relative to the build volume, as shown, for example, in Figure 1. The projection units may be positioned off-center and / or may include light focusing means, as shown in Figure 2B, such that the patterns provided by each projection unit are virtually aligned across the build volume. In this example, the light / projection area of ​​each pattern is provided at a specific angle of incidence, depending on the position of the projection unit relative to the focal plane of the unit and the area of ​​this focal plane that a particular projection unit is arranged to illuminate. However, one or more, for example all, of the projection units may be arranged perpendicular to the focal plane to illuminate an allocated area of ​​the focal plane (as shown in Figure 2B). In such a case, the pattern is not provided obliquely to the focal plane. However, as can be seen from Figure 2B, providing the pattern obliquely to the focal plane may contribute to further improving spatial resolution, as each projection unit illuminates each respective focal plane with more pixels.

[0061] In some embodiments of this disclosure, each subsinogram needs to be shifted vertically according to the difference between its projection orientation and the reference plane. In this way, a virtual alignment of the projection unit, for example, as shown in Figure 2B, may be generated.

[0062] In some embodiments of this disclosure, the reference plane is the focal plane of one of the projection units. Typically, the reference plane and / or focal plane intersect the rotation center of the build volume and / or the rotation center of the projection unit around the build volume. Typically, the rotation center is the physical center of the build volume, such as in the horizontal plane when the axis of rotation is the vertical axis. However, in other embodiments, the focal planes of multiple projection units may be located at different positions within the build volume, for example, the focal planes may be located at different distances from the center of the build volume. Thus, multiple projection units may be arranged to have focal planes at different distances along the optical axis, for example, at different positions with respect to the center of the build volume.

[0063] In some embodiments of this disclosure, the output curves of the projection units are unified. Calibration is required when calculating print patterns for various projection units. The correlation between gray value and output power generally differs for each projector (especially if they are not of the same brand). The desired gray value I2' for projection unit 2 is calculated so that the light patterns produce exactly the same output for different projection units (projectors 1 and 2), even if their "gray value-output power" correlations are different.

number

[0064] Projection unit The number of projection units that can be used to generate a three-dimensional object can theoretically be unlimited. In some embodiments, different projection units may be different types of projectors, such as DLP, LEP, LCD, and / or other types of projection units such as digital micromirror devices. Thus, projection units may have the same or different resolutions, i.e., spatial resolution and / or temporal resolution. Furthermore, projection units may have different illumination powers. Therefore, projection units may be projection units of different models and / or brands.

[0065] As used herein, the term "projection system" refers to a system comprising multiple projection units. The projection units of a projection system are typically located apart from each other but are positioned to illuminate a build volume for the purpose of manufacturing a three-dimensional object. Typically, the build volume is illuminated while rotating.

[0066] In some embodiments of this disclosure, the pattern is illuminated by a projection unit. Any type of system capable of illuminating the build volume with a series of patterned lights can be used as a projection unit. Typical examples of projection units are optoelectronic systems such as DLP projectors, LED projectors, LCD projectors, laser projectors, spatial light modulators, and digital micromirror devices that can be coupled with light sources. Furthermore, the projection unit may be a light source such as an LED covered with microlenses. Furthermore, the projection unit may be part of a projection system, which comprises an array of light sources such as an OLED array covered with microlenses. Other projection units are known to those skilled in the art.

[0067] In some embodiments of this disclosure, a series of patterns of light are projected by a projection unit, such as when the projection unit is a DLP projector. In DLP projectors, such as conventional three-channel DLP projectors having red, green, and blue color channels, each pixel in an image or image frame has intensity values ​​for the red, green, and blue components that together form the pixel. To realize the intensity values ​​for each component, each mirror in the micromirror array of the DMD is controlled to be rapidly turned on and off (i.e., directed toward or away from the projection environment) to generate light pulses that together form the desired intensity. The process of rapidly controlling the on / off state of the micromirrors is sometimes called a pulse sequence or mirror flip sequence.

[0068] In some embodiments of this disclosure, a series of patterns of light are projected by a projection unit, such as when the projection unit is an LED projector. In operation, the LED projector of this subject may operate in one or more projection modes. A projection mode can be understood as a configuration of the LED projector used for projecting data.

[0069] In some embodiments of the present disclosure, a series of patterns of light are projected by a projection unit, such as when the projection unit is an LCD projector.

[0070] In some embodiments of this disclosure, the pattern is illuminated by a projection unit, such as when the projection unit is a laser projector. The laser projector may have various laser light sources, which may include at least one laser transmitter capable of emitting light of at least one color. Generally, the laser light source may also include a fluorescence wheel (also referred to as a fluorescence color wheel) that can function as a wavelength conversion device. The laser light source may be a monochromatic laser light source (i.e., including one type of laser transmitter that produces one color) or a dichromatic laser light source (i.e., including two types of laser transmitters, each producing one color) that emit lasers of one or two colors. The fluorescence wheel comprises a fluorescence powder that can be excited to produce fluorescence of the corresponding color, and the fluorescence powder, together with the color of the laser emitted by the laser transmitter, jointly form three primary colors, thereby functioning as a projection light source for providing illumination to optical components. The light source component of the laser projector includes at least a laser transmitter and a fluorescence wheel. The optical components of a laser projector include at least an imaging element and a projection lens, and the imaging element may be a DMD element or an LCOS element.

[0071] In some embodiments of this disclosure, the multiple projection units are located apart from each other. In some embodiments of this disclosure, the focal planes of the projection units are aligned.

[0072] In some embodiments of this disclosure, the number of projection units is unlimited. In some embodiments of this disclosure, the number of projection units is at least 2, for example at least 5, for example at least 10, for example at least 100, for example at least 1000. Theoretically, the number of projection units is unlimited.

[0073] In some embodiments of this disclosure, each projection unit is configured to project light at an activation wavelength, preferably including the activation wavelength of a photosensitive component, such as the activation wavelength of a photopolymerization initiator. In some embodiments, the wavelength includes a spectral range of wavelengths such as spectral peaks having spectral peaks in the ranges of 25 nm, 50 nm, 75 nm, 100 nm, 125 nm, and 200 nm on both sides of the spectral peak. In some embodiments of this disclosure, each projection unit irradiates the build volume with the same wavelength. In some embodiments of this disclosure, each projection unit irradiates the build volume with different wavelengths, such as a difference of at least 1 nm, e.g., a difference of at least 5 nm, e.g., a difference of at least 50 nm, e.g., a difference of at least 100 nm, e.g., a difference of at least 500 nm. In some embodiments of this disclosure, each projection unit irradiates the build volume with different wavelengths, such as a difference of less than 500 nm, e.g., a difference of less than 100 nm, e.g., a difference of less than 50 nm, e.g., a difference of less than 5 nm, e.g., a difference of less than 1 nm.

[0074] In some embodiments of this disclosure, the activation wavelength is in the UV (ultraviolet) range. In some embodiments of this disclosure, the activation wavelength is in the visible light range.

[0075] In some embodiments of this disclosure, the step of irradiating is: • Illuminating the build volume with multiple patterns of light, defined by the subsinogram assigned to the corresponding projection unit, each of the multiple projection units individually. Each projection unit is positioned apart from one another, and the projection unit is positioned at a different orientation angle with respect to the build volume (e.g., the center of the build volume), including projection. The build volume may be positioned to rotate around an axis of rotation that intersects the center of the build volume. Typically, the axis of rotation is perpendicular to the plane of the projection units, but one or more projection units, e.g., all of them, may be located outside this plane. For example, one or more projection units, e.g., all of them, may be located in a different plane, such as a plane perpendicular to the axis of rotation relative to the build volume. Alternatively or additionally, the projection units may be positioned to revolve / rotate around the build volume.

[0076] In some embodiments of this disclosure, the pattern light is irradiated in a maskless process, such as without a photomask.

[0077] resolution The resolution of a projection unit refers to the number of pixels available for projection onto the build volume. By combining the resolutions of multiple projection units according to this disclosure, the overall resolution of the system is improved. As a result, the resolution of the sinogram can also be improved, and furthermore, the resolution (number of voxels) of the formed object can also be improved.

[0078] Accordingly, the projection units of this disclosure may have a specific resolution. Depending on the desired properties of the object being formed, certain parts of the object may be illuminated with a higher pixel density (number of pixels per unit area) than other parts. In such cases, one or more of the projection units may be positioned to illuminate the part where a higher pixel density is desired, while one or more other projection units may be positioned to illuminate other parts of the object where a lower pixel density is formed.

[0079] Therefore, improving resolution results in 1) an increase in total volume, given that the size of each pixel and / or voxel is kept constant, and / or 2) an increase in the total number of voxels used to define a three-dimensional object, given that the total volume is kept constant.

[0080] In some embodiments of the present disclosure, spatial resolution can be improved by maintaining the size of each voxel while increasing the total volume. In some embodiments of the present disclosure, spatial resolution can be improved by maintaining the total volume while increasing the total number of voxels contained in the total volume.

[0081] As used herein, the term voxel refers to each of the arrays of volumetric elements that constitute a conceptual three-dimensional space, particularly each of the arrays of discrete elements to which a representation of a three-dimensional object, such as a three-dimensional object, is divided. Voxel size is typically determined by the print resolution. Smaller voxels (i.e., higher print resolution) typically reproduce a higher degree of detail and allow for higher print accuracy. The size of a voxel can be the resolution in this way, since the properties of a three-dimensional object are defined for each voxel of that object. In contrast, a point or pixel usually refers to an individual point, such as the smallest addressable individual element.

[0082] In some embodiments of this disclosure, each projection unit has a maximum resolution.

[0083] In some embodiments of the present disclosure, spatial resolution can be improved in the vertical and / or horizontal directions. Figure 4A shows an embodiment of the present disclosure in which virtual alignment is arranged to improve both vertical and horizontal resolution. In this example, four projection units with different aspect ratios are used, and each projection unit is arranged to illuminate a different portion of the focal plane. The virtual alignment also includes overlapping portions, which can be used to improve the resolution of objects in the corresponding portions or to suppress them by blocking at least a portion of the light from one or more projectors in the overlapping areas.

[0084] In some embodiments of this disclosure, the spatial resolution is limited by the size of the photosensitive component.

[0085] In some embodiments of this disclosure, a three-dimensional object is reproduced in several voxels of the build volume, and the calculation steps include defining sub-sinograms of the sinogram and assigning each sub-sinogram to a single projection unit. The derivation of the sub-sinograms may be based on the position and / or orientation of the projection unit relative to the center of the build volume. In one example, a sinogram, such as one used in a simple system with a single projection unit illuminating the build volume, is divided into multiple sub-sinograms, each sub-sinogram associated with a projection unit, and the radial angle is shifted based on the position of the projection unit. However, the sub-sinograms may be further modified based on whether the projection unit is out of the plane and / or its orientation relative to the center of the build volume.

[0086] In some embodiments of this disclosure, the spatial resolution of each point of the reproduced three-dimensional object is defined by the sum of the resolutions of each projection unit. In some embodiments of this disclosure, the horizontal resolution of each point of the reproduced three-dimensional object is defined by the sum of the resolutions of each projection unit. In some embodiments of this disclosure, the vertical resolution of each point of the reproduced three-dimensional object is defined by the sum of the resolutions of each projection unit.

[0087] refresh rate Theoretically, if the number of projection units is unlimited, the temporal resolution is unlimited. In some embodiments, the temporal resolution is improved by synchronizing the illumination of multiple projection units, thereby resulting in a virtual frame rate higher than the frame rate of each individual projection unit. Each projection unit is typically individually positioned to illuminate a set of light patterns corresponding to the subsinogram of each individual projection unit, and the subsinograms are radially shifted to compensate for the position and / or orientation of a particular projection unit (thus forming a virtual radial alignment of the projection units). However, furthermore, each projection unit may be positioned to illuminate the build volume with a specific delay, typically given by dividing the refresh rate of the projection unit by the number of projection units. In this way, the resulting illumination may correspond to using a single projection unit with a refresh rate equal to the sum of the refresh rates of the projection units in the above example. Thus, by improving the temporal resolution (i.e., frame rate) of the system, better temporal resolution is achieved.

[0088] Furthermore, the use of multiple projection units allows for increased power output (e.g., Mw / cm²), which enables shorter printing times. 2 This results in ( ). In such cases, it may not be necessary to synchronize the illumination of the projection unit.

[0089] In some embodiments of this disclosure, the spatial and temporal resolution of each point of the reproduced three-dimensional object is improved.

[0090] In some embodiments of the present disclosure, each projection unit has a maximum refresh rate. In some embodiments of the present disclosure, the temporal resolution of each point of the reproduced three-dimensional object is defined by the sum of the refresh rates of each projection unit.

[0091] In some embodiments of the present disclosure, the projection of each projection unit is delayed by 1 / fn, where f is the refresh rate and n is the number of projection units.

[0092] In some embodiments of this disclosure, the total power output provided to the build volume is the sum of the power outputs of each individual projection unit.

[0093] depth of field The ultra-high-speed 3D printing of TVP is contingent on sufficient power output from the projection unit used to illuminate the build volume. The larger the aperture of the projection unit, the greater the power output. At the same time, it is advantageous to illuminate with a depth of field larger than the dimensions of the workpiece, for example, to ensure the same manufacturing accuracy across the entire workpiece.

[0094] Therefore, in the case of a single projection unit system, the aperture size may limit the output power used to illuminate the build volume in order to have a depth of field that is at least the length of the workpiece, for example, along the optical axis. This results in, as mentioned above, an increase in printing time, for example, if the aperture is small enough so that the depth of field is at least the distance of the workpiece / object being formed.

[0095] As disclosed elsewhere in this specification, to offset this, multiple projection units can be combined in such a way that their individual irradiations result in the same three-dimensional energy distribution. Thus, the power output / intensity provided by each projection unit to irradiate the build volume are added together to reduce the printing time.

[0096] Furthermore, instead of using multiple projection units, each having a depth of field at least the distance along the optical axis of the workpiece, the build volume may be illuminated by multiple projection units, each having a larger aperture and consequently a greater power output, but consequently a shorter depth of field. By virtually aligning these projection units, they can be collectively made to have a depth of field over the distance of the workpiece, for example, along the optical axis, thereby reducing printing time, as shown in Figures 11-12.

[0097] photosensitive component As used herein, the term "photosensitive component" refers to a material that changes its properties when exposed to electromagnetic radiation, typically light in the visible and / or ultraviolet region. These changes often manifest structurally; for example, the curing of a material occurs as a result of cross-linking upon exposure to light. The material may contain photopolymerization initiators and / or photosensitizers to be activated by this electromagnetic radiation. Activation can result in polymerization of other parts of the photosensitive component, such as monomers and / or prepolymers.

[0098] As used herein, the term prepolymer refers to a monomer or monomer system that is reacting to an intermediate molecular weight state that can be polymerized to a higher molecular weight state by a reactive group, or can be further polymerized.

[0099] In some embodiments of this disclosure, the prepolymer is selected from a list including acrylate monomers, epoxy monomers, or combinations thereof. In some embodiments of this disclosure, the prepolymer is an acrylate monomer. In some embodiments of this disclosure, the prepolymer is an epoxy monomer.

[0100] In one embodiment of the present disclosure, the photosensitive component comprises a prepolymer, such as a monomer, and a photoactivator, such as a photosensitizer, a photopolymerization initiator, or a mixture thereof. Preferably, the photosensitive component is configured to be activated by irradiation with light, and this activation causes polymerization of the prepolymer. Activation usually occurs by the activation of a photoactivator, and usually the polymerization of the prepolymer occurs by catalytic action. Generally, photoactivators are easily activated within a specific wavelength range / wavelength distribution. For photopolymerization initiation to proceed efficiently, the absorption band of the photopolymerization initiator must overlap with the emission spectrum of the light source, i.e., the wavelength distribution used for polymerization of that particular photosensitive component, and preferably, competing absorption by the formulation components at the wavelength corresponding to the excitation of the photopolymerization initiator must be minimized.

[0101] In some embodiments of the present disclosure, the photosensitive component is capable of photochemical reactions upon irradiation with light at an activation wavelength. The activation wavelength and / or irradiation wavelength may each include, or consist of, a single wave, a wavelength band / wavelength range, or a wavelength distribution comprising multiple wavelengths, such as multiple distinct wavelengths.

[0102] As used herein, the term photoinitiator refers to a molecule that, upon irradiation with light, absorbs photons (typically at a specific wavelength(s)), forming reactive species from an excited state, which then sequentially initiate reactions. These initiator species may be radicals, cations, or anions. Different photoinitiators are distinguished by the wavelength range in which they exhibit high-energy absorption, and are therefore readily described by their characteristic absorption spectra. Thus, the selection of the excitation light source wavelength and the composition of the photoinitiator are usually closely related.

[0103] In some embodiments of the present disclosure, the photopolymerization initiator is selected from a list including free radical photopolymerization initiators, cationic photopolymerization initiators, or combinations thereof. In some embodiments of the present disclosure, the photopolymerization initiator is a free radical photopolymerization initiator. In some embodiments of the present disclosure, the photopolymerization initiator is a cationic photopolymerization initiator.

[0104] Photopolymerization initiators are molecules that are sensitive to light. When they absorb light, they undergo photochemical cleavage, generating reactive species (either free radicals, Brønsted or Lewis acids) that interact with the active ingredients in the formulation.

[0105] There are two classes of photoinitiators: Type I and Type II. Type I photoinitiators cause monomolecular bond cleavage after light absorption, yielding reactive species. These photoinitiators do not require other species to function. Type II photoinitiators cause bimolecular reactions. After light absorption, the photoinitiator reaches an excited state, from which it reacts with another molecule (co-initiator or synergist) to generate reactive species. Photosensitizers are molecules that cause chemical changes in other molecules during a photochemical process.

[0106] As used herein, the term polymerization refers to the process of chemically reacting molecules of a prepolymer and / or monomer to form a polymer chain or three-dimensional network. Photopolymerization is typically a chain polymerization initiated by the absorption of visible or ultraviolet light. The light may be absorbed directly by the reactant monomers (direct photopolymerization) or by a photosensitizer or photopolymerization initiator.

[0107] In some embodiments of this disclosure, photochemical reactions cause polymerization of the build volume in the irradiated voxels.

[0108] In one embodiment of this disclosure, the photosensitive component(s) are: • Prepolymers such as monomers, • A photopolymerization initiator that is activated when irradiated with light having an activation wavelength, Activation of the photopolymerization initiator polymerizes the prepolymer.

[0109] Relative angle Preferably, the orientation and / or position of at least one of the build volume and projection units is changed during the irradiation of the build volume. For example, the projection unit can rotate around the build volume, such that the projection is always directed toward the center of the build volume, such as the horizontal center, while the build volume is stationary. Alternatively, the build volume can rotate around an axis of rotation that is usually perpendicular to the projection plane. As is known to those skilled in the art, several configurations of positioning and / or orientation of the build volume and projection unit are possible for reconstructing a three-dimensional object. In some embodiments, multiple projection units are used, and the projection units are positioned at separate locations, for example, each projection unit may be positioned at the corresponding position of each projection.

[0110] As previously mentioned, multiple configurations of the projection unit and build volume are possible and are known to those skilled in the art in the field of tomography vat photopolymerization. In some embodiments of the present disclosure, the build volume rotates about a vertical axis of rotation intersecting the center of the build volume. In some embodiments of the present disclosure, the light of these patterns is produced by a projection unit that projects the light of these patterns substantially parallel to the plane of rotation of the build volume. In some embodiments of the present disclosure, the light of these patterns is produced by a projection unit that projects the light of these patterns substantially perpendicular to the plane of rotation of the build volume. In some embodiments of the present disclosure, the light of the patterns rotates around the build volume and is produced by a projection unit that projects the light of these patterns toward the build volume.

[0111] Purpose Printing technology can be used to create three-dimensional objects from the data output of computerized modeling sources. For example, a user can design a three-dimensional object using a computer program, and the computer can output the design data to a system capable of forming a solid three-dimensional object, such as the system of this disclosure.

[0112] In some embodiments of the present disclosure, the build volume contains cells, and the system may be arranged so that the cells are incorporated into a three-dimensional object when the build volume is irradiated.

[0113] In some embodiments of this disclosure, the three-dimensional object is an artificial tissue for purposes such as in vitro drug screening or in vivo implantation.

[0114] In some embodiments of this disclosure, the volume to be built contains cells such as undifferentiated stem cells, for example, iPS cells.

[0115] In some embodiments of this disclosure, the three-dimensional object is a personalized earmold for a hearing aid or earphone for music.

[0116] In some embodiments of this disclosure, the three-dimensional object is a custom seal for swimming goggles.

[0117] In some embodiments of this disclosure, the three-dimensional object is a microfluidic device.

[0118] In some embodiments of this disclosure, the three-dimensional object is a lab-on-a-chip device or an organ-on-a-chip device.

[0119] In some embodiments of this disclosure, the pattern light is generated and / or irradiated by a DLP projector, an LED projector, an LCD projector, and / or a laser projector. Generally, it is preferable that the pattern is irradiated onto the build volume during a maskless process, such as by not using a photomask. In some embodiments of this disclosure, the pattern is generated by a DLP projector. In some embodiments of this disclosure, the pattern is generated by an LED projector. In some embodiments of this disclosure, the pattern is generated by an LCD projector. In some embodiments of this disclosure, the pattern is generated by a laser projector. In some embodiments of this disclosure, the pattern is irradiated by a DLP projector. In some embodiments of this disclosure, the pattern is irradiated by an LED projector. In some embodiments of this disclosure, the pattern is irradiated by an LCD projector. In some embodiments of this disclosure, the pattern is irradiated by a laser projector.

[0120] In some embodiments of this disclosure, the method is a computer implementation method or a processor implementation method.

[0121] system In some embodiments of this disclosure, the system is configured to perform a method for manufacturing a three-dimensional object, as disclosed elsewhere in this specification.

[0122] As used herein, the term "orientation adjustment unit" refers to a system configured to control the relative orientation of the build volume and / or projection unit. For example, an orientation adjustment unit may include one configured to rotate the build volume, for instance, while the projection unit is stationary, thereby illuminating the build volume from multiple orientations. Alternatively or additionally, the projection unit may rotate around the build volume. Typically, the rotation and / or movement is in the horizontal plane, but it may be in any plane.

[0123] In a further aspect, the disclosure relates to a system for manufacturing three-dimensional objects.

[0124] In some embodiments of the present disclosure, the projection system comprises a plurality of projection units selected from a list including a spatial light modulator, a digital micromirror device, a galvanometer scanner, or an acousto-optic deflector.

[0125] In some embodiments of this disclosure, the projection system comprises a spatial light modulator. In some embodiments of this disclosure, the projection system comprises a digital micromirror device. In some embodiments of this disclosure, the projection system comprises a galvanometer scanner. In some embodiments of this disclosure, the projection system comprises an acousto-optic deflector. In some embodiments of this disclosure, the projection system comprises a light source, or a light source for each projection unit.

[0126] In some embodiments of this disclosure, the light source includes one or more incandescent light bulbs, such as halogen bulbs, or one or more fluorescent lamps, such as lasers, LEDs, or discharge lamps. In some embodiments of this disclosure, the light source comprises halogen lamps. In some embodiments of this disclosure, the light source comprises one or more light-emitting lamps. In some embodiments of this disclosure, the light source comprises a laser. In some embodiments of this disclosure, the light source comprises an LED. In some embodiments of this disclosure, the light source comprises a discharge lamp.

[0127] Furthermore, in some embodiments of this disclosure, the pattern is illuminated by a projection unit. Any type of system capable of illuminating the build volume with a series of patterned lights can be used as a projection unit. Typical examples of projection units are optoelectronic systems such as DLP projectors, LED projectors, LCD projectors, laser projectors, spatial light modulators, and digital micromirror devices that can be coupled with light sources. Furthermore, the projection unit may be a light source such as an LED covered with microlenses. Furthermore, the projection unit may be part of a projection system, which comprises an array of light sources such as an OLED array covered with microlenses. Other projection units are known to those skilled in the art. Other types of projection units are disclosed elsewhere in this specification.

[0128] In some embodiments of the present disclosure, the orientation adjustment unit is configured to rotate the build volume within the illumination area of ​​the projection unit, and / or to rotate the projection unit relative to the build volume.

[0129] In some embodiments of the present disclosure, the system comprises a direction adjustment unit. Preferably, the direction adjustment unit is configured to controllably vary the incident direction of light of these patterns onto the build volume. The direction adjustment unit can rotate the build volume and / or projection system. Preferably, this rotation is configured such that, during the irradiation step, light of the patterns is projected onto the build volume at multiple angles. The direction adjustment unit may further include the movement of mirrors and / or lenses, where the illumination source of the projection unit and the build volume are fixed in place and do not rotate, but the direction adjustment unit may include several lenses configured so that light of several patterns is projected onto the build volume at corresponding angles and corresponding wavelengths, as defined in a calculation step by a processing unit.

[0130] In some embodiments of the present disclosure, the system comprises a controller. Preferably, the controller is configured to control the orientation unit and / or projection unit. More preferably, the controller is configured to control the projection unit and the orientation unit so that the build volume is illuminated by a pattern of light controlled by an activation wavelength from directions corresponding to different orientation angles. The controller may be a computer, which may further comprise a processing unit.

[0131] In some embodiments of the present disclosure, the system comprises a receptacle, such as a container for housing the build volume, which is optically transparent to light for these patterns. The receptacle is preferably cylindrical, but may have a polyhedral shape. For example, the receptacle may be a polygon with vertically protruding sides, such as a pentagon or a decagon. In such cases, the system may comprise a single projection unit positioned to illuminate each face of the polyhedral receptacle.

[0132] In some embodiments of the present disclosure, the processing unit is configured to calculate the projection, the material to be used, and / or the corresponding orientation angle. In some embodiments of the present disclosure, the processing unit is configured to control a controller. In some embodiments of the present disclosure, the processing unit is configured to calculate the projection. In some embodiments of the present disclosure, the processing unit is configured to calculate the material to be used. In some embodiments of the present disclosure, the processing unit is configured to calculate the corresponding orientation angle.

[0133] In some embodiments of this disclosure, the method includes providing a build volume which typically contains several components that polymerize into an object when exposed to light, such as light of a specific wavelength.

[0134] It should be noted that the embodiments disclosed herein may be modified or combined without departing from the concept of the invention.

[0135] For example, as shown in Figures 1 to 4, the horizontal and / or vertical resolution may be improved by virtual alignment of the projection units (i.e., virtual alignment of the illumination of the projection units). Such improvement in horizontal and / or vertical resolution may be combined with improvement in temporal resolution, which depends on the timing of the projection units, as disclosed elsewhere in this specification, for example in Figure 6. Furthermore, improvement in horizontal and / or vertical resolution, and / or temporal resolution, may be combined with the use of multiple partially or fully overlapping projection units (e.g., fully overlapping, identical illumination patterns) to maintain or reduce printing time. Alternatively or additionally, improvement in resolution may be combined with the use of multiple projection units arranged to have focal planes at different distances along the optical axis (e.g., different distances from the center of the build volume), thereby making the combined depth of field greater than the distance across the build volume along the optical axis (e.g., as shown in Figures 11 to 12).

[0136] Accordingly, this disclosure relates to several different strategies for improving resolution (e.g., spatially, such as vertical and / or horizontal, or temporally) while maintaining and / or reducing printing time by aligning multiple projection units, for example, by arranging multiple overlapping projection units to illuminate the build volume with the same focal plane, thereby increasing the intensity of illumination provided to the build volume. Alternatively or additionally, multiple projects may be arranged at different positions through the build volume, having focal planes shifted along the optical axis. In this way, collectively, projection units with larger apertures and shorter depths of field can be used, while having a depth of field equal to or greater than the length of the build volume along the optical axis, or at least the size of the object formed along this optical axis.

[0137] Detailed description of the drawing The present invention will be described in more detail below with reference to the accompanying drawings. The drawings are illustrative and intended to illustrate some of the features of the methods and systems of the present disclosure for manufacturing three-dimensional objects, and should not be construed as limiting the invention of the present disclosure.

[0138] Figure 1 shows an example of a system of the present disclosure comprising a plurality of projection units (1-4). The projection units illuminate the photosensitive component (14) within the build volume (13) from different orientation angles (9-12) that are typically perpendicular to their respective focal planes. Each projector (1-4) projects onto a different focal plane (5-8). Each projector may have a different resolution and refresh rate. The projection units are arranged such that, by each of the plurality of projection units, the build volume is illuminated with light containing the activation wavelength of the photosensitive component at the corresponding orientation angle, using the projection of a series of light patterns corresponding to one of a set of subsinograms, and each projection unit illuminates the build volume with a series of light patterns derived from a different set of subsinograms, and as a result, the build volume is irradiated with a series of light patterns resulting from the corresponding set of subsinograms at the corresponding orientation angles. This illumination can result in the formation of a three-dimensional object (15).

[0139] Figure 2 shows a virtual alignment of the projection areas of multiple projection units. Specifically, Figure 2A shows how the methods and related systems of this disclosure may be used to improve the spatial resolution of the object being formed (e.g., the number of voxels and / or pixels used by the projection units to form this object). A high-resolution sinogram (18) is calculated, containing 11,619 pixels per row at a horizontal resolution (16). The number of pixels exceeds the resolution of any of the projection units. Therefore, none of the projection units used have enough pixels to project this sinogram. As shown in Figure 2B, four projection units (1-4) are used to illuminate the build volume with a series of resulting patterns of light corresponding to the sinogram at the corresponding orientation angles. It should be noted that a sinogram typically corresponds to only a single (vertical) layer of the build volume; therefore, projection units are arranged to illuminate the build volume with a set of light patterns, each corresponding to a set of sinograms, where each sinogram in the set corresponds to a single layer of the build volume, for example, where the layer thickness defines the (vertical) size of the voxel. In this example, projection units (1-4) contribute 2203, 4406, 1280, and 3730 pixels, respectively. Each projection (39-42) is performed by illuminating the build volume with a set of light patterns, each corresponding to a set of sub-sinograms. A set of sub-sinograms may be obtained, for example, by dividing a set of sinograms, where each sinogram and set of sinograms corresponds to a layer of the object.

[0140] The projections (39-42) are aligned on their respective focal planes (5-8 in Figure 1) to illuminate different or partially overlapping portions of the virtual focal plane (37). The object is defined between the edges (38) of the illuminated area. In this way, the projection units (1-4) are aligned along the virtual focal plane (37), resulting in improved resolution.

[0141] Figure 3 shows the physical alignment of the four projection units in this embodiment. Figure 3A shows that one sinogram, i.e., one layer (11,619 horizontal pixels), is divided into four subsinograms (19). The horizontal resolutions of the subsinograms are 3730 pixels, 1280 pixels, 4406 pixels, and 2203 pixels from left to right, and are projected using projection units 4, 3, 2, and 1, respectively. In order to project a series of patterns of light corresponding to the set of subsinograms for the formation of an object, the subsinograms (and / or sets of subsinograms) must be compensated for the orientation angle of each projection unit. Thus, by shifting the angular index of each subsinogram (and / or set of subsinograms) by a degree that reflects the difference between the projection direction (θ) and the reference plane (e.g., the focal plane), the contribution of each projection unit during the illumination step of the build volume may correspond to having a single projection unit with sufficient resolution to accurately project the set of sinograms (i.e., the entire object at full resolution). Here, the focal plane (37) is used as the reference plane. The angular index (17) is shifted and adjusted. Figure 3C shows that, physically, only one projection exists on each focal plane (5-8), but as described above, each projection provides a contribution to a virtual focal plane to generate a higher-resolution three-dimensional object.

[0142] Figure 4 shows an example of virtual alignment of multiple projections, each based on a set of subsinograms, to improve horizontal and vertical resolution by using multiple projection units, four in this example. Figure 4A shows a schematic diagram of the build volume perpendicular to the axis of rotation. The projections (39-42) of the four projection units, each containing a series of light patterns corresponding to a set of subsinograms, are combined in a manner that improves spatial resolution. As can be seen from the figure, the projection units may be arranged to improve vertical resolution (by illuminating different horizontal layers of the build volume) and / or to improve horizontal resolution by illuminating different parts of the virtual focal plane, as described above. The projection units may be arranged to improve both virtual and horizontal resolution. Furthermore, the projections may overlap each other, as can be seen from the figure. In those areas, it may be advantageous to compensate the power output of the projection units so that all areas are provided with the correct amount of illumination for the formation of a three-dimensional object. Alternatively, as can be seen from Figure 4B, a single projection unit may be arranged to illuminate these areas.

[0143] Figure 5 shows calibration according to an embodiment of the present disclosure, which may be required when calculating print patterns for various projection units. The correlation between gray value (20) and output power (25) generally differs for each projector (21-24), especially if they are not of the same brand. The desired gray value I2' for projection unit 2 is calculated so that the light patterns produce exactly the same output for different projection units (projectors 1 and 2), even if their “gray value-output power” correlations are different.

number

[0144] Figure 6 shows a schematic diagram illustrating how the temporal resolution can be improved in tomography vat polymerization by synchronizing multiple projection units (1-4). The number of projection units may be at least two, but there is no theoretical upper limit to the number of projection units. Furthermore, each projection unit may have an arbitrary orientation angle, which may be compensated by shifting the set of sinograms, as described, for example, in Figure 3. Preferably, all projection units have the same refresh rate, e.g., 60 Hz, and the projection of each subsequent projection unit after the first projection unit is delayed by 1 / fn, where f is the refresh rate and n is the number of projection units. Thus, by having four projection units with a refresh rate of 60 Hz, projection unit 2 may have a delay of 1 / 240 seconds, projection unit 3 may have a delay of 2 / 240 seconds, and projection unit 3 may have a delay of 3 / 240 seconds. In this way, the illumination of the build volume corresponds to the illumination of projection units with a refresh rate of 240 Hz. The methods and systems of this disclosure for improving temporal resolution may be combined with methods and systems for improving spatial resolution. However, temporal resolution may be improved by using projection units, each positioned to illuminate the build volume with a series of light patterns corresponding to a set of sinograms, from their respective corresponding orientation angles (9 to 12).

[0145] Figure 7 shows a flowchart outlining a method for manufacturing a multi-material three-dimensional object according to a particular embodiment of the present disclosure. The method may include a compute (26) step, which includes computed a set of several subsinograms, each set of subsinograms derived from a set of sinograms, each sinogram describing layers of a three-dimensional object formed from different orientation angles. The method may further include a provide (27) step, which includes providing a build volume containing a photosensitive component capable of initiating a photochemical reaction upon irradiation with light of an activation wavelength. The method may further include an irradiate (28) step, which includes irradiating the build volume with light containing an activation wavelength at a corresponding orientation angle using a set of light projections by each of several projection units, each projection unit irradiating the build volume with a set of light patterns derived from different sets of subsinograms, so that as a whole the build volume is irradiated with a set of light patterns resulting from the corresponding sets of sinograms at the corresponding orientation angles.

[0146] Figure 8 shows a flowchart outlining a method for manufacturing a multi-material three-dimensional object according to a particular embodiment of the present disclosure. The method may include a compute (29) step, which includes computed a set of sinograms describing three-dimensional objects formed from different orientation angles. The method may further include a provide (30) step, which includes providing a build volume containing a photosensitive component capable of initiating a photochemical reaction upon irradiation with light of an activation wavelength. The method may further include an irradiate (31) step, which includes irradiating the build volume at the corresponding orientation angles using a series of light projections corresponding to the set of sinograms, each of a plurality of projection units having the same refresh rate f, wherein the irradiated light includes an activation wavelength, and at least one of the projection units is positioned to irradiate the build volume with projections at the corresponding orientation angles with a delay of 1 / (f·n) given by the other projection units, where n is a natural number.

[0147] Figure 9 shows a flowchart outlining a method for manufacturing a multi-material three-dimensional object according to a particular embodiment of the present disclosure. The method may include a compute (43) step, which includes computed a set of sinograms describing three-dimensional objects formed from different orientation angles. The method may further include a provide (44) step, which includes providing a build volume containing a photosensitive component capable of initiating a photochemical reaction upon irradiation with light of an activation wavelength. The method may further include an irradiate (45) step, which includes irradiating the build volume with each of a plurality of projection units using a series of light projections corresponding to a set of sinograms at a corresponding orientation angle, wherein the irradiated light includes an activation wavelength.

[0148] Figure 10 shows a tomography vat photopolymerization system for manufacturing a three-dimensional object from a build volume, according to a particular embodiment of the present disclosure. The figure shows a system in which the build volume is housed by a receptacle (33). An exemplary system comprises a projection system including two projection units (34 and 36), namely a first projection unit and a second projection unit. As shown, the system may include an optical system (35), such as a lens, between the projector and the receptacle. The receptacle is suspended from an orientation adjustment unit (32), illustrated herein as a turntable, while it is fixed in place. Thereafter, the build volume can be rotated, and the projector units irradiate several patterns of light in their respective corresponding orientations.

[0149] Figure 11 shows an example of a system of the present disclosure comprising a plurality of projection units (1-4). The system shown comprises four projectors, but any number of projectors is possible, as disclosed elsewhere in this specification. The projection units are arranged to illuminate the photosensitive component (14) of the build volume (13). Each projector (1-4) projects onto a different focal plane (5-8). Thus, the first projector (1) has a first focal plane (5), the second projector (2) has a second focal plane (6), the third projector (3) has a third focal plane (7), and the fourth projector (4) has a fourth focal plane (8).

[0150] As disclosed elsewhere in this specification, projection units may have different resolutions and / or refresh rates and may be positioned in different vertical planes, i.e., in different positions along the viewing axis of the figure. Note that while the figure shows projectors with different orientation angles relative to the build volume, this is not a requirement. In fact, a subset of projectors, or even all of them, may have the same orientation angle relative to the build volume. Projectors may be stacked on top of each other, for example, and therefore have the same (radial) orientation angle relative to the build volume.

[0151] In one example, the projector has different focal planes, meaning the focal planes are positioned differently in the build volume.

[0152] The projection units (1-4) can typically be positioned along the optical axis of the projection unit to have a depth of field across the workpiece (i.e., the object to be formed, or alternatively, the build volume). As disclosed elsewhere in this specification, a common method for increasing the depth of field is to reduce the aperture of the projection unit. However, this is associated with the disadvantage of reduced output power. To compensate for this, multiple projection units, each having a depth of field across the workpiece, may be virtually aligned such that each of them produces a similar or identical three-dimensional energy distribution as a result of its respective illumination. The projection units may, for example, be positioned so that each has a depth of field across the workpiece or even the build volume. The projection units may, for example, be positioned to illuminate the build volume, and each may have a focal plane that intersects the center of rotation and / or the center of the build volume (e.g., as shown in Figure 1). Thus, the projection units may be positioned to produce the same three-dimensional object, but by virtually aligning them (or in this case, virtually superimposing their sets of light patterns), the printing time is reduced.

[0153] However, alternatively, the projection units (1-4) may be arranged such that each projection unit has a focal plane shifted relative to the other units. For example, the projection units may have focal planes (1-4) selected, taking into account the depth of field of the projection units, such that the resulting depth of field spans the workpiece and / or build volume, for example, along the optical axis. The projection units may have one or more, for example, different, depths of field shorter than the distance of the three-dimensional object. By virtually aligning the focal planes, the build volume can be illuminated by multiple projection units, and the resulting combined depth of field of all projection units spans the distance of the three-dimensional object, for example, along the optical axis. Thus, each projection unit can be said to contribute to the distance of the three-dimensional object, for example, from its respective orientation angle. The total depth of field of all projection units may span the three-dimensional unit, for example, along the optical axis of each projection unit.

[0154] As can be seen from Figure 11, the focal planes are shifted along the virtual optical axis of the projection unit. Here, the fourth focal plane (4) is the closest to the projection unit, the second focal plane (2) is the second closest, the first focal plane is the third closest, and the third focal plane is the fourth closest. In this way, the focal planes are positioned so that the depth of field of the projection unit collectively spans the entire workpiece and / or build volume, for example, along the optical axis.

[0155] Figure 12 further illustrates the effective depth of field (48) of multiple projection units, where the individual depths of field (47) and individual focal planes (5-8) are selected such that the effective depth of field extends across the entire workpiece and / or the entire build volume, for example, along the optical axis. In this way, printing time can be reduced, and / or projection units with shorter depths of field can be used for efficient printing of workpieces larger than the depth of field of the individual projection units. Thus, the focal planes are virtually aligned, each collectively having an effective depth of field (47) across the workpiece and / or build volume, for example, along the optical axis of the projection unit.

[0156] Figure 13A shows an example of a system of the present disclosure comprising multiple projection units (1-3). The system shown comprises three projectors, but any number of projectors is possible, as disclosed elsewhere in this specification. The projection units are arranged to irradiate the photosensitive component (14) of the build volume (13). Each projector (1-3) projects onto a different focal plane (5-7). Thus, the first projector (1) has a first focal plane (5), the second projector (2) has a second focal plane (6), and the third projector (3) has a third focal plane (7). In the example shown, multiple sets of subsinograms are calculated from a set of sinograms, and each projector unit is arranged to irradiate the build volume with a different set of subsinograms. Therefore, the set of subsinograms is derived by equally dividing the set of sinograms among the projection units, so that each projection unit is positioned to illuminate the build volume from a corresponding orientation angle defining a sector of 2π / n, where n is the number of projection units. In this way, three-dimensional objects can be manufactured faster and more accurately. For example, the first projection unit (1) may be positioned to illuminate the build volume from the first sector (49), the second projection unit (2) may be positioned to illuminate the build volume from the second sector (50), and the third projection unit (3) may be positioned to illuminate the build volume from the third sector (51). Each sector may be 2π / n in this example, where n is the number of projection units, e.g., 3. Figure 13B shows the subsinogram (18) derived from the sinogram. The subsinogram can describe a single layer of a three-dimensional structure. The subsinograms are derived by dividing the sinogram by angular index, so that each subsinogram has an angular index range of 2π / n. In this example, the first projection unit (1) may be positioned to illuminate the build volume with a series of light patterns derived from the first subsinogram (52), the second projection unit (2) from the second subsinogram (53), and the third projection unit (3) from the third subsinogram (54).

[0157] item 1. A method for manufacturing a three-dimensional object, The calculation involves calculating a set of multiple subsinograms, where each set of subsinograms is derived from a set of sinograms, and each sinogram describes layers of the three-dimensional object formed from different orientation angles. To provide a build volume containing a photosensitive component that can initiate a photochemical reaction when irradiated with light of an activation wavelength, The process includes irradiating the build volume with light containing the activation wavelength at a corresponding orientation angle, using a series of light projections corresponding to one of the sets of subsinograms by each of the multiple projection units, The method, wherein each projection unit illuminates the build volume with a series of light patterns derived from a different set of subsinograms, so that the build volume is illuminated with a series of light patterns resulting from the set of subsinograms at the corresponding orientation angles.

[0158] 2. The method of any of the preceding items, wherein the set of subsinograms is derived, for example, by dividing the set of sinograms once or more times.

[0159] 3. The method according to item 2, wherein the set of subsinograms is derived by dividing the set of sinograms according to one or more radial indices and / or one or more angular indices and / or one or more vertical indices.

[0160] 4. The method according to any of the preceding items, wherein the set of sinograms is divided into the same number of subsinogram sets as the number of projection units used to illuminate the build volume, for example, the same number of subsinogram sets as the number of projection units.

[0161] 5. The method according to any of the preceding items, wherein the set of sinograms is divided into a set of sub-sinograms based on the number of pixels and / or aspect ratio of the projection unit.

[0162] 6. The method according to any of the preceding items, wherein the projection unit is positioned to have a focal plane intersecting the center of the build volume.

[0163] 7. The method of any of the preceding items, wherein the projection units are arranged to be virtually aligned to illuminate different portions of their respective focal planes, and when the respective focal planes are superimposed, the portions are connected or partially overlap, for example, improving spatial resolution along the focal planes.

[0164] 8. The method according to any of the preceding items, wherein the projection unit is positioned to illuminate different parts of the build volume for the formation of the three-dimensional object, the parts being connected or partially overlapping, and having different radial positions with respect to a rotation axis traversing the build volume, and / or vertical positions between the parts.

[0165] 9. The method according to any one of the preceding items, wherein the series of patterns of light irradiated by different projection units have a different number of pixels per unit length along the distance of their respective focal planes.

[0166] 10. The method of any of the preceding items, wherein the projections of the different projection units have different numbers of pixels per unit length in the horizontal and / or vertical directions at the focal plane, and for example, a portion of the three-dimensional object which is more preferably more clearly defined is assigned to have a greater number of pixels per unit length.

[0167] 11. The method according to any one of items 1 to 5, wherein the projection unit is positioned to have a focal plane intersecting the center and / or center of rotation of the build volume, and the depth of field of the projection unit is adapted to span the length of the three-dimensional object / workpiece, for example, along the optical axis.

[0168] 12. The method according to any one of items 1 to 5, wherein the depth of field of the projection unit is shorter than the distance of the three-dimensional object, for example along the optical axis, and the focal plane of the projection unit is selected such that the resulting composite depth of field extends over the three-dimensional object, for example along the optical axis.

[0169] 13. The method according to item 12, wherein the focal plane of each projection unit is shifted along the optical axis.

[0170] 14. The method according to items 12-13, wherein each projection unit is arranged to have a focal plane located at a different distance from the center of the build volume, for example, along the optical axis.

[0171] 15. The method of any of the preceding items, wherein the set of sinograms is divided into sets of subsinograms by dividing the set of sinograms by a radial index such that at least two sets of subsinograms have different corresponding orientation angles.

[0172] 16. The method of item 15, wherein the angular index of the set of subsinograms is shifted, for example, with respect to the build volume, to compensate for the relative angular orientation of the projection unit.

[0173] 17. The irradiating step is: • Illuminating the build volume with multiple patterns of light defined by the set of subsinograms assigned to the corresponding projection unit, each of the multiple projection units, The method according to any one of the preceding items, comprising irradiating, wherein each projection unit is positioned apart from one another, the build volume rotates relative to the projection unit, and the rotation has an axis of rotation parallel to the focal plane of the projection unit.

[0174] 18. The method according to any one of the preceding items, wherein the three-dimensional object is reproduced in a plurality of voxels of the build volume, and the calculation step includes defining a set of subsinograms of the set of sinograms and assigning each set of subsinograms to one projection unit.

[0175] 19. The method of any of the preceding items, wherein each set of subsinograms is derived by vertically shifting the set of subsinograms according to the difference between the orientation angles of the focal planes of the projection unit.

[0176] 20. The method according to any one of the preceding items, wherein the three-dimensional object to be formed is described by a set of sinograms such that one sinogram describes one layer of the three-dimensional object, and the thickness of the layer is the size of the voxel, e.g., the vertical size of the voxel.

[0177] 21. A method for manufacturing a three-dimensional object, • Calculating a set of sinograms describing the three-dimensional object formed from different orientation angles, To provide a build volume containing a photosensitive component that can initiate a photochemical reaction when irradiated with light of an activation wavelength, The method comprising irradiating the build volume at a corresponding orientation angle using projection of a series of light patterns corresponding to the set of sinograms by each of a plurality of projection units having the same refresh rate f, wherein the irradiating light includes the activation wavelength.

[0178] 22. The method according to item 21, wherein at least one of the projection units is positioned to illuminate the build volume with the projection at the corresponding orientation angle with respect to the other projection units, with a delay of 1 / (f·n), where n is a natural number.

[0179] 23. The method according to item 22, wherein n is the number of projection units used to illuminate the build volume with the series of light patterns.

[0180] 24. Each of the plurality of projection units is

number

[0181] 25. A method for manufacturing a three-dimensional object, • Calculating a set of sinograms describing the three-dimensional object formed from different orientation angles, To provide a build volume containing a photosensitive component that can initiate a photochemical reaction when irradiated with light of an activation wavelength, The method comprising irradiating the build volume using projections of a series of patterns of light corresponding to the set of sinograms at corresponding orientation angles by each of a plurality of projection units, wherein the irradiating light includes the activation wavelength.

[0182] 26. The method of any of the preceding items, wherein the power supplied to the build volume during the irradiation step is equal to the total power output of the projection unit.

[0183] 27. The method according to any one of the preceding items, wherein the plurality of sinograms are used to describe the three-dimensional object being formed, typically one sinogram for each vertical voxel of the object, for example, each voxel of the object perpendicular to the build volume and / or the axis of rotation of the projection unit.

[0184] 28. The method according to any one of the preceding items, wherein the photochemical reaction results in polymerization of the molding volume in the irradiated voxel.

[0185] 29. The method according to any one of the preceding items, comprising the step of calculating the sinogram, for example, a tomography reconstruction filter after a radon transform, a tomography reconstruction filter after a fan beam algorithm, and / or a tomography reconstruction filter after a cone beam algorithm.

[0186] 30. The method described in any one of the preceding items, wherein the sinogram is calculated using any one of the following lists: a tomography reconstruction filter after radon transform, a tomography reconstruction filter after a fan beam algorithm, a tomography reconstruction filter after a cone beam algorithm, an iterative reconstruction technique, an algebraic reconstruction technique, or a diffraction tomography algorithm.

[0187] 31. The method of any of the preceding items, wherein the projection unit is arranged to begin irradiating the build volume substantially simultaneously, and / or the projection unit is arranged to end irradiating the build volume substantially simultaneously.

[0188] 32. The photosensitive component is • Prepolymers such as monomers, The photopolymerization initiator is activated when irradiated with light having the aforementioned activation wavelength, The method according to any one of the preceding items, wherein the activation of the photopolymerization initiator is performed to polymerize the prepolymer.

[0189] 33. The photopolymerization initiator is selected from a list including free radical photopolymerization initiators, cationic photopolymerization initiators, or combinations thereof, as described in any one of the preceding items.

[0190] 34. The method according to any one of the preceding items, wherein the photosensitive component is configured to be activated by irradiation with light, and the activation results in polymerization of the prepolymer.

[0191] 35. The prepolymer is selected from a list containing acrylate monomers or epoxy monomers, as described in any one of the preceding items.

[0192] 36. The method according to any one of the preceding items, wherein the activation wavelength is in the UV range.

[0193] 37. The method according to any one of the preceding items, wherein the activation wavelength is within the visible light range.

[0194] 38. The method according to any one of the preceding items, wherein the light of the pattern is generated by a projection unit that projects the light of the pattern substantially parallel to the plane of rotation of the build volume.

[0195] 39. The method according to any one of the preceding items, wherein the light of the pattern is generated by a projection unit that projects the light of the pattern substantially perpendicular to the plane of rotation of the build volume.

[0196] 40. The method according to any one of the preceding items, wherein the light of the pattern is generated by a projection unit that rotates around the build volume and projects the light of the pattern toward the build volume.

[0197] 41. The method according to any one of the preceding items, wherein the build volume includes cells, and the cells are arranged such that they are incorporated into the three-dimensional object when the build volume is irradiated.

[0198] 42. The method according to any one of the preceding items, wherein the three-dimensional object is an artificial tissue, such as for in vitro drug screening or in vivo implantation.

[0199] 43. The method according to any one of the preceding items, wherein the volume to be formed includes cells such as undifferentiated stem cells, for example, iPS cells.

[0200] 44. The method described in any one of the preceding items, used for printing personalized earmolds for hearing aids or music earphones.

[0201] 45. The method according to any one of the preceding items, wherein the three-dimensional object is, for example, a custom seal for swimming goggles, a microfluidic device, a lab-on-a-chip device and / or an organ-on-a-chip device.

[0202] 46. ​​The projection unit is selected from the list including DLP projectors, LED projectors, LCD projectors, laser projectors, spatial light modulators and / or optoelectromechanical systems, such as digital micromirror devices, according to any one of the preceding items.

[0203] 47. The method according to any one of the preceding items, wherein the pattern is irradiated by a maskless process.

[0204] 48. A system for manufacturing a three-dimensional object, wherein the system is A processing unit configured to compute multiple sets of subsinograms, wherein each set of subsinograms is derived from a set of sinograms, and each sinogram describes layers of the three-dimensional object formed from different orientation angles, • A build volume containing a photosensitive component capable of undergoing a photochemical reaction when irradiated with light of an activation wavelength, A projection system comprising a plurality of projection units capable of irradiating the build volume with a series of light patterns including the activation wavelength, • A direction adjustment unit for controllingly changing the direction of light incidence from the projection unit relative to the build volume, The system comprises: a controller configured to control the orientation adjustment unit and the projection system such that each of the multiple projection units projects a series of light patterns corresponding to one of the set of subsinograms, so that the build volume is illuminated with light including the activation wavelength at a corresponding orientation angle; The method, wherein each projection unit illuminates the build volume with a series of light patterns derived from a different set of subsinograms, and as a result, the build volume is illuminated collectively with a series of light patterns resulting from the set of sinograms corresponding to the corresponding orientation angles.

[0205] 49. A system for manufacturing a three-dimensional object, wherein the system is A processing unit configured to compute a set of sinograms describing the three-dimensional object formed from different orientation angles, • A build volume containing a photosensitive component capable of undergoing a photochemical reaction when irradiated with light containing an activation wavelength, A projection system comprising multiple projection units having the same refresh rate and capable of irradiating the build volume with a series of light patterns including the activation wavelength, • A direction adjustment unit for controllingly changing the direction of light incidence from the projection unit relative to the build volume, The system comprises: a controller configured to control the orientation adjustment unit and the projection system so that the build volume is illuminated at a corresponding orientation angle using a series of light projections corresponding to the set of sinograms, wherein the illumination light includes the activation wavelength, and at least one of the projection units is positioned to illuminate the build volume with the projection at the corresponding orientation angle with respect to the other projection units, with a delay given by 1 / (f·n), where n is a natural number; and the controller.

[0206] 50. A system for manufacturing a three-dimensional object, wherein the system is A processing unit configured to compute a set of sinograms describing the three-dimensional object formed from different orientation angles, • A build volume containing a photosensitive component capable of undergoing a photochemical reaction when irradiated with light containing an activation wavelength, A projection system comprising a plurality of projection units capable of irradiating the build volume with a series of light patterns including the activation wavelength, • A direction adjustment unit for controllingly changing the direction of light incidence from the projection unit relative to the build volume, The system comprises: a controller configured to control the orientation adjustment unit and the projection system so that the build volume is illuminated by projecting a series of light patterns corresponding to the set of sinograms at corresponding orientation angles, wherein the illuminated light includes the activation wavelength.

[0207] 51. A system for manufacturing a three-dimensional object, wherein the system is A processing unit configured to compute a set of sinograms describing the three-dimensional object formed from different orientation angles, • A build volume containing a photosensitive component capable of undergoing a photochemical reaction when irradiated with light containing an activation wavelength, A projection system comprising a plurality of projection units capable of illuminating the build volume with a series of light patterns including the activation wavelength, wherein each projection unit has a depth of field longer than the three-dimensional object and / or the build volume, for example, along the optical axis, and the focal plane of each projection unit is positioned to intersect with the center of rotation and / or the center of the build volume, • A direction adjustment unit for controllingly changing the direction of light incidence from the projection unit relative to the build volume, The system comprises: a controller configured to control the orientation adjustment unit and the projection system so that the build volume is illuminated by each of the plurality of projection units using a series of light projections corresponding to the set of sinograms at a corresponding orientation angle, wherein the illumination light includes the activation wavelength; and the system.

[0208] 52. A system for manufacturing a three-dimensional object, wherein the system is A processing unit configured to compute a set of sinograms describing the three-dimensional object formed from different orientation angles, • A build volume containing a photosensitive component capable of undergoing a photochemical reaction when irradiated with light containing an activation wavelength, A projection system comprising a plurality of projection units capable of illuminating the build volume with a series of light patterns including the activation wavelength, wherein the projection units have a depth of field shorter than the three-dimensional object and / or the build volume, for example along the optical axis, and the focal plane of each projection unit is positioned, for example along the optical axis, such that the depth of field extends over the length of the three-dimensional object and / or the build volume, • A direction adjustment unit for controllingly changing the direction of light incidence from the projection unit relative to the build volume, The system comprises: a controller configured to control the orientation adjustment unit and the projection system so that the build volume is illuminated by each of the plurality of projection units using a series of light projections corresponding to the set of sinograms at a corresponding orientation angle, wherein the illumination light includes the activation wavelength; and the system.

[0209] 53. The system described in any one of items 48 to 52, configured to perform the method described in any one of items 1 to 47.

Claims

1. A method for manufacturing a three-dimensional object, - Calculating a set of multiple subsinograms, each set of subsinograms being derived from a set of sinograms, each sinogram describing layers of the three-dimensional object formed from different orientation angles, - To provide a build volume containing a photosensitive component that can initiate a photochemical reaction when irradiated with light of an activation wavelength, - Irradiating the build volume with light containing the activation wavelength at a corresponding orientation angle, using a series of light projections corresponding to one of the sets of subsinograms by each of the multiple projection units, The method, wherein each projection unit illuminates the build volume with a series of light patterns derived from a different set of subsinograms, so that the build volume is illuminated with a series of light patterns resulting from the set of subsinograms at the corresponding orientation angles.

2. The method according to claim 1, wherein the set of subsinograms is derived in a process comprising dividing the set of sinograms into the same number of sets of subsinograms as the number of projection units used to illuminate the build volume.

3. The method according to any one of the prior claims, wherein the set of subsinograms is derived in a process comprising dividing the set of sinograms at least once according to a radial index.

4. The method according to any one of the prior claims, wherein the set of subsinograms is derived in a process comprising dividing the set of sinograms at least once, and as a result, the set of subsinograms describes different layers of the three-dimensional object formed from different orientation angles, for example, in the vertical direction.

5. The method according to any one of the prior claims, wherein the set of subsinograms is derived in a process comprising shifting the orientation angle of at least one set of subsinograms according to the difference between the angles of the focal planes of the projection unit.

6. The method according to any one of the prior claims, wherein the series of light patterns irradiated by different projection units have a different number of pixels per unit length along the distance between their respective focal planes.

7. The method according to any one of the prior claims, wherein each projection unit is arranged to have a focal plane intersecting the center of the build volume, and the projection units are arranged to be virtually aligned to illuminate different portions and / or partially overlapping portions of their respective focal planes.

8. The method according to any one of the prior claims, wherein the projection unit is positioned to have a focal plane intersecting the center and / or center of rotation of the build volume, and the depth of field of the projection unit is adapted to span the length of the three-dimensional object / workpiece, for example, along the optical axis.

9. The method according to any one of claims 1 to 6, wherein the projection unit has one or more depths of field shorter than the distance of the three-dimensional object, for example along the optical axis, and the focal plane of the projection unit is selected such that the resulting composite depth of field spans the distance of the three-dimensional object, for example along the optical axis.

10. The method according to claim 9, wherein the focal planes of each projection unit are located at different positions, for example, along the optical axis.

11. The method according to claims 9 to 10, wherein each projection unit is arranged to have a focal plane located at a different distance from the center of the build volume, for example, along the optical axis.

12. The aforementioned irradiation step is, The method according to any one of the prior claims, comprising illuminating the build volume with a plurality of patterns of light defined by a set of subsinograms assigned to the corresponding projection unit, each of the plurality of projection units.

13. The method according to claim 11, wherein the projection unit is positioned, for example, at different orientation angles with respect to the center of the build volume.

14. The method according to any one of the prior claims, wherein the molding volume rotates relative to the projection unit.

15. A method for manufacturing a three-dimensional object, - Calculate a set of sinograms describing the three-dimensional object formed from different orientation angles, - To provide a build volume containing a photosensitive component that can initiate a photochemical reaction when irradiated with light of an activation wavelength, The method comprising: illuminating the build volume using a series of light projections by each of a plurality of projection units, so that the build volume is illuminated with a series of light patterns resulting from corresponding to a set of sinograms at corresponding orientation angles, the illumination light includes the activation wavelength, the projection units have one or more depths of field shorter than the distance of the three-dimensional object, for example along the optical axis, and the focal plane of each projection unit is selected such that the resulting combined depth of field from all projection units spans the distance of the three-dimensional object, for example along the optical axis.

16. The method according to claim 15, wherein the focal planes of each projection unit are located at different positions, for example, along the optical axis.

17. The method according to claims 15 to 16, wherein each projection unit is arranged to have a focal plane that is located at a different distance from the center of the build volume, for example, along the optical axis.

18. The method according to any one of the prior claims, wherein the molding volume rotates relative to the projection unit.

19. A method for manufacturing a three-dimensional object, - Calculate a set of sinograms describing the three-dimensional object formed from different orientation angles, - To provide a build volume containing a photosensitive component that can initiate a photochemical reaction when irradiated with light of an activation wavelength, The method comprising: illuminating the build volume using a series of light projections by each of a plurality of projection units, wherein the build volume is illuminated with a series of light patterns resulting from the projection of a set of sinograms at corresponding orientation angles, the illumination light includes the activation wavelength.

20. The method according to claim 19, wherein each projector unit illuminates the build volume with the same series of light patterns.

21. The method according to claim 19, further comprising the step of calculating a set of subsinograms from the set of sinograms, wherein the illuminating step comprises illuminating the build volume with projections of a series of light patterns corresponding to one of the sets of subsinograms by each of a series of projection units, so that the build volume is illuminated with a series of light patterns resulting from the results corresponding to the set of sinograms at the corresponding orientation angles.

22. The method according to claim 21, wherein the set of subsinograms is derived by equally dividing the set of sinograms among the set of projection units, so that each projection unit is positioned to illuminate the build volume from a corresponding orientation angle defining a sector of 2π / n, where n is the number of projection units.

23. The method according to claim 19, wherein the projection units have the same refresh rate f, and at least one of the projection units is positioned to illuminate the build volume with the projection at the corresponding orientation angle with respect to the other projection units (or more), with a delay of 1 / (f・n), where n is a natural number.

24. n is the number of projection units used to illuminate the build volume with the series of light patterns, and each of the plurality of projection units is [Math 1] The method according to claim 23, wherein i is given by and i is a distinct natural number for each projection unit in the interval [1, n].

25. A system for manufacturing a three-dimensional object, wherein the system is A processing unit configured to compute a set of sinograms, each sinogram describing layers of the three-dimensional object formed from different orientation angles, - A build volume arranged to accommodate photosensitive components capable of undergoing photochemical reactions when irradiated with light of an activation wavelength, A projection system comprising a plurality of projection units capable of irradiating the build volume with a series of light patterns including the activation wavelength, The system comprises: a controller configured to control the projection system such that the build volume is irradiated with light containing the activation wavelength at a corresponding orientation angle, using the projection of a series of light patterns corresponding to one of the set of sinograms by each of a plurality of projection units.

26. A system for manufacturing a three-dimensional object, wherein the system is A processing unit configured to compute multiple sets of subsinograms, wherein each set of subsinograms is derived from a set of sinograms, and each sinogram describes layers of the three-dimensional object formed from different orientation angles, - A build volume arranged to accommodate photosensitive components capable of undergoing photochemical reactions when irradiated with light of an activation wavelength, A projection system comprising a plurality of projection units capable of irradiating the build volume with a series of light patterns including the activation wavelength, - A direction adjustment unit for controllingly changing the direction of light incidence from the projection unit relative to the build volume, The system comprises: a controller configured to control the orientation adjustment unit and the projection system such that each of the multiple projection units projects a series of light patterns corresponding to one of the sets of subsinograms, so that the build volume is illuminated with light including the activation wavelength at the corresponding orientation angle; The method, wherein each projection unit illuminates the build volume with a series of light patterns derived from a different set of subsinograms, and as a result, the build volume is illuminated collectively with a series of light patterns resulting from the set of sinograms corresponding to the corresponding orientation angles.

27. A system for manufacturing a three-dimensional object, wherein the system is A processing unit configured to compute a set of sinograms describing the three-dimensional object formed from different orientation angles, - A build volume containing a photosensitive component capable of undergoing a photochemical reaction when irradiated with light containing an activation wavelength, A projection system comprising a plurality of projection units capable of irradiating the build volume with a series of light patterns including the activation wavelength, - A direction adjustment unit for controllingly changing the direction of light incidence from the projection unit relative to the build volume, The system comprises: a controller configured to control the orientation adjustment unit and the projection system so that the build volume is illuminated by each of the plurality of projection units using a series of light projections corresponding to the set of sinograms at a corresponding orientation angle, wherein the illumination light includes the activation wavelength; and

28. The system according to claim 27, wherein the controller is configured to control the orientation adjustment unit and the projection system so that the build volume is illuminated at the corresponding orientation angle using projection of a series of patterns of light corresponding to the set of sinograms, the illumination light includes the activation wavelength, and at least one of the projection units is positioned to illuminate the build volume with the projection at the corresponding orientation angle with a delay of 1 / (f・n) relative to the other projection units, where n is a natural number.

29. A system for manufacturing a three-dimensional object, wherein the system is A processing unit configured to compute a set of sinograms describing the three-dimensional object formed from different orientation angles, - A build volume containing a photosensitive component capable of undergoing a photochemical reaction when irradiated with light containing an activation wavelength, A projection system comprising a plurality of projection units capable of illuminating the build volume with a series of light patterns including the activation wavelength, wherein the projection units have a depth of field longer than the three-dimensional object, for example, along the optical axis, and the focal plane of each projection unit is positioned to intersect the center of rotation and / or the center of the build volume, - A direction adjustment unit for controllingly changing the direction of light incidence from the projection unit relative to the build volume, The system comprises: a controller configured to control the orientation adjustment unit and the projection system so that the build volume is illuminated by each of the plurality of projection units using a series of light projections corresponding to the set of sinograms at a corresponding orientation angle, wherein the illumination light includes the activation wavelength; and

30. A system for manufacturing a three-dimensional object, wherein the system is A processing unit configured to compute a set of sinograms describing the three-dimensional object formed from different orientation angles, - A build volume containing a photosensitive component capable of undergoing a photochemical reaction when irradiated with light containing an activation wavelength, - A projection system comprising a plurality of projection units capable of illuminating the build volume with a series of light patterns including the activation wavelength, wherein the projection units have a depth of field shorter than the three-dimensional object, for example along the optical axis, and the focal plane of each projection unit is arranged, for example along the optical axis, such that the depth of field extends over the length of the three-dimensional object, - A direction adjustment unit for controllingly changing the direction of light incidence from the projection unit relative to the build volume, The system comprises: a controller configured to control the orientation adjustment unit and the projection system so that the build volume is illuminated by each of the plurality of projection units using a series of light projections corresponding to the set of sinograms at a corresponding orientation angle, wherein the illumination light includes the activation wavelength; and

31. The system according to any one of claims 25 to 30, wherein the system is configured to perform the method described in any one of claims 1 to 24.

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