High-throughput three-dimensional printing system

Abstract

Three-dimensional (3D) printing methods, systems and devices are described that enable high speed printing of multiple objects using two or more objective lenses and with a large field of view. One example optical system for 3D laser printing includes one or more beamsplitters that are configured to receive a collimated optical laser beam and to produce a plurality of optical beams. The optical system also includes a plurality of objective lenses, each positioned to receive one of the plurality of optical beams, and to focus the received optical beam onto a focal plane that is shared by all of the plurality of objective lenses. The focal plane coincides with a position of 3D printable material, and upon illumination of the 3D printable material by the beams received from the plurality of objective lenses, a plurality of 3D-printed objects are simultaneously generated.

Description

HIGH-THROUGHPUT THREE-DIMENSIONAL PRINTING SYSTEMCROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] This application claims priority to the provisional application with serial number 63 / 606,266 titled “HIGH-THROUGHPUT THREE-DIMENSIONAL PRINTING SYSTEM,” filed December 5, 2023. The entire contents of the above noted provisional application are incorporated by reference as part of the disclosure of this document.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

[0002] This invention was made with government support under Grant No. CA268190 awarded by National Institutes of Health. The government has certain rights in the invention.TECHNICAL FIELD

[0003] The disclosure of this patent document relates to three dimensional printing systems and methods.BACKGROUND

[0004] Additive manufacturing (AM), or three-dimensional (3D) printing, offers a promising solution to directly fabricate complex objects. A variety of AM techniques, such as stereolithography (SLA), digital light processing (DLP), and two-photon polymerization (TPP), have been investigated to print objects using different materials. Each of these techniques, however, have certain shortcomings that include, among others, limited field of view (FOV) and low throughput.SUMMARY

[0005] The disclosed embodiments relate to TPP printing methods, systems and devices that overcome the limitations of prior systems, and among other features and benefits, enable higher speed printing with more than one objective and with a large FOV.

[0006] One example optical system for 3D laser printing includes one or more beamsplitters configured to receive a collimated optical laser beam and to produce a plurality of optical beams,and a plurality of objectives, each positioned to receive one of the plurality of optical beams, and to focus the received optical beam onto a focal plane that is shared by all of the plurality of objectives, where the focal plane coincides with a position of 3D printable material. Upon illumination of the 3D printable material by the beams received from the plurality of objectives, a plurality of 3D-printed objects are simultaneously generated.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. lillustrates a configuration of a three-dimensional (3D) printing system with four large field of view microscope objectives in accordance with an example embodiment.

[0008] FIG. 2 illustrates an example system that uses a processor or controller in conjunction with a 3D printing system in accordance with an example embodiment.

[0009] FIG. 3 illustrates a set of operations that can be carried out to produce a plurality of 3D-printed objects in accordance with an example embodiment.DETAILED DESCRIPTION

[0001] Of the three previously mentioned additive manufacturing techniques, TPP 3D printing offers several key advantages. First, it is highly material efficient, as only the necessary amount of material is used to fabricate a part, reducing material waste and costs. Second, it is energy efficient, as fewer steps, no tools, no molds, and less time are needed to fabricate complex elements. Third, it offers flexibility in design, as freeform surfaces and microstructures can be printed, which is not possible with traditional fabrication methods.

[0002] The current two-photon polymerization (TPP) printing systems have two major limitations. The first one is that the printing field of view (FOV) is small since the commercial objective used in a typical TPP printing system usually has a small FOV, limiting its capability in printing objects larger than about 1.0 mm. While stitching methods can be used to create larger elements, they are not ideal for optical elements. This is because optical surfaces require exceptional high quality, and even small inconsistencies at the junctions of stitched areas can significantly impair image quality. Additionally, the restricted FOV of the objective lens limits the ability to print larger or multiple elements, even with advanced manufacturing techniques.

[0003] The second disadvantage of TPP is that the printing system typically has only one printhead, which means only one object can be printed in each process, limiting its throughput. This limitation arises from the nature of the printing process, which involves focusing laser beams to induce polymerization in a localized region. Researchers are exploring strategies to optimize the printing process, such as improving laser scanning techniques and developing multi-beam printing processes that can simultaneously print multiple components. While these methods can print several elements under one objective through one printing process, they still suffer from the limitation that the FOV of commercial high-NA objectives is small, which results in the printed elements to be very small.

[0004] The low throughput of two-photon polymerization printing can hinder the scalability and efficiency of production, particularly for high-volume manufacturing where large quantities are needed within a short timeframe.

[0005] The disclosed technology can be implemented in various embodiments of TPP printing systems and methods that overcome the limitations of the existing TPP printing systems, and, among other features and benefits, enable printing systems with more than one objective, having a large FOV.

[0006] FIG. 1 illustrates a configuration of a printing system with four large FOV microscope objectives in accordance with an example embodiment. In this example configuration, the laser is collimated first and then directed to the scanner. After the relay lens, the laser beam is split into two beams by the first beamsplitter, and is then split again by the second and third beamsplitters to produce four beams. The relay lens relays the scanner aperture to the entrance pupil of each objective. The positions of the four objectives are aligned so that their focal points are in the same plane. To enable simultaneous printing, the four objectives share with the same material tray. Alternatively, each of the four objectives can have its own material tray mounted on the same scanning stage. In some embodiments, one or more movable stages (e.g., X-, Y-, Z- movable stage) is coupled to one or more trays that accommodate the 3D-printable material.

[0007] The example system depicted in FIG. 1, which features four microscope objectives, can print four identical objects simultaneously in a single printing session. By employing a high-powerlaser, the system can be further enhanced with additional objectives, thus significantly boosting its overall throughput.

[0008] To facilitate the printing of larger objects without the need for stitching, the FOV of each high NA objective must be sufficiently large. For example, for a 1.0 NA objective, the FOV should be no less than 1.5 mm, while for a 0.8 NA objective, it should be at least 2.0 mm. In some embodiments, these FOV requirements can increase; for example, the FOV can be at least 2.0 mm fora 1.0 NA objective, 3.0 mm for a 0.8 NA objective, and 5.0mm for a 0.6 NA objective, enabling the creation of larger scale objects with high precision.

[0009] To achieve a larger FOV while maintaining a compact diameter for high NA objectives, in some embodiments, aspherical surfaces are integrated into the lens design. These aspherical surfaces are key in minimizing aberrations. Additionally, they contribute to reducing the number of lens elements required, which in turn enhances light transmission efficiency.

[0010] In contrast to commercial microscope objectives, which need to correct aberrations across a broad spectrum, the TPP (two-photon polymerization) printing system typically utilizes a narrow laser beam, such as a 780 nm femtosecond laser. This specificity in wavelength allows for the objectives in the TPP system to be optimized for aberration correction over a narrower spectrum, streamlining the design process and potentially improving system performance.

[0011] While the example configuration in FIG. 1 with four microscope objectives is shown to facilitate the description, it is understood that the disclosed technology can be implemented in other configurations. For example, in some configurations, eight objective lenses can be used. More generally, the number of objective lenses can be any power of 2. Even further, the optical beam can be split into an odd number of beams (e.g., 3 beams, 5 beams, etc.) using various beamsplitters (or combinations thereof). For example, in some configurations, a polygon beam splitter can be used. In general, the beam splitters can include prisms, gratings or other types of technologies that allow an input beam to be split into two or more beams. In some embodiments, the input beam’s intensity is split evenly into multiple beams (e.g., a 50-50 split when an input beam is split into two output beams). In some embodiments, the input beam is not split evenly. For example, in some embodiments, the split ratio 70-30, while in other example embodiments, the split ratio is 80-20.

[0012] Furthermore, in the example configuration of FIG. 1, all objectives are identical. It should be noted, however, that in some embodiments, the objectives can be different. For example, at least one of the objectives can have a different magnification (and / or FOV, NA, etc.) than other objectives to allow printing of the same object but at a different size compared to objects that are printed by other objectives. Additionally, in the configuration of FIG. 1, the optical axis of optical system is rotated 90 degrees (optical beam that exits the scanner is rotated by 90 degrees by the time it reaches the material tray). It is however understood that in other configurations, the components of the printing systems may be positioned to provide other degrees of rotation, or no rotation.

[0013] The disclosed technology in some embodiments relates to high throughput printing systems that include an ultrafast laser, more than one identical large field of view printing obj ective for focusing the laser light to the printing material, where the focal points of the objectives are in the same plane. In some embodiments, the objectives share the same material tray. For example, the ultrafast laser can be a femtosecond laser with a central wavelength between 775nm to 785nm. In another example, the ultrafast laser is a femtosecond laser with a central wavelength between 520nm to 535nm. In yet another example, the femtosecond laser has a central wavelength between l,000nm to l,100nm.

[0014] In one example embodiment, each of the objectives has a field of view that is larger than 1.5 mm and an NA larger than 1.0. In another example, each of the objectives has a field of view larger than 2.0 mm and an NA larger than 0.8. In yet another example embodiment, each of the objectives has a field ofview larger than 2.0 mm and an NA larger than 1.0. In still another example, each of the objectives has a field of view larger than 3.0 mm and an NA larger than 0.8. In another example, each of the objectives has a field of view larger than 5.0 mm and an NA larger than 0.6.

[0015] In one example configuration, the system has four objectives, while in another example configuration, the system has eight objectives.

[0016] Some of the operations disclosed herein can be implemented using a processor / controller is configured to include, or be coupled to, a memory that stores processor executable code that causes the processor / controller carry out various computations and processing of information. FIG. 2 illustrates an example system that uses a processor or controller 202. Theprocessor / controller 202 can further generate and transmit / receive suitable information to / from the various system components, as well as suitable input / output (IO) capabilities (e.g., wired or wireless) to transmit and receive commands and / or data. The processor / controller 202 may, for example, provide signals to control the operation of various components such as the 3D printing system 206, illumination sources 204 (e.g., lasers) and movable stages 208 that are disclosed herein. The processor / controller 202 may be further configured to perform various method steps and computations that are disclosed in this patent document.

[0017] FIG. 3 illustrates a set of operations that can be carried out to produce a plurality of 3D- printed objects in accordance with an example embodiment. At 302, laser illumination is provided to a scanner that configured to direct the laser illumination to an optical printing head. The optical head includes: one or more beamsplitters configured to receive the laser illumination and to produce a plurality of optical beams, and a plurality of objectives, each positioned to receive one of the plurality of optical beams, and to focus the received optical beam onto a focal plane that is shared by all of the plurality of objectives. The focal plane coincides with a position of 3D printable material to allow 3D printing of one layer of each of the plurality of 3D objects. At 304, a position of the 3D printable material is moved to allow printing of one or more additional layers of each of the plurality of 3D objects.

[0018] One aspect of the disclosed embodiments relates to an optical system for 3D laser printing that includes one or more beamsplitters configured to receive a collimated optical laser beam and to produce a plurality of optical beams, and a plurality of objectives, each positioned to receive one of the plurality of optical beams, and to focus the received optical beam onto a focal plane that is shared by all of the plurality of objectives. The focal plane coincides with a position of 3D printable material, wherein upon illumination of the 3D printable material by the beams received from the plurality of objectives a plurality of 3D-printed objects are simultaneously generated.

[0019] In one example embodiment, each beamsplitter is configured to evenly divide an intensity of an optical beam that is incident thereon, and each of the plurality of objectives is identical to any other of the plurality of objectives to allow simultaneous generation the plurality of substantially identical 3D-printed objects. In another example embodiment, the 3D-pritinablematerial is coupled to a moveable stage that allows the 3D-printable material to move in X-, Y- or Z-directions. I yet another example embodiment, the optical system includes a single tray that accommodates the 3D printable material corresponding to the plurality of objectives, wherein the single tray is configured to move in X-, Y- or Z-directions. In still another example embodiment, the optical system includes a plurality of trays, where each tray is configured to accommodate the 3D printable material corresponding to one of the plurality of objectives, wherein each of the plurality of trays is configured to move in X-, Y- or Z-directions.

[0020] According to another example embodiment, at least one of the plurality objectives provides a different magnification than another of the plurality of objectives to allow simultaneous generation of 3D-pinted objects, wherein at least one of the plurality of 3D-printed objects has a different size compared to at least another one of the 3D-printed objects. In another example embodiment, the optical system is part of a two-photon polymerization (TPP) 3D printing system, and each of the plurality of objectives is configured to compensate for aberrations over only a range of wavelengths corresponding to laser illumination associated with the TPP 3D printing system. In one example embodiment, the laser illumination is provided by a femtosecond laser with a central wavelength in a range 775 nm to 785 nm. In another example embodiment, the laser illumination is provided by a femtosecond laser with a central wavelength in a range 520 nm to 535 nm. In yet another example embodiment, the laser illumination is provided by a femtosecond laser with a central wavelength in a range 1,000 nm to 1, 100 nm.

[0021] In one example embodiment, the plurality of objectives consists of four objectives, and in another example embodiment, the plurality of objectives consists of eight objectives. In still another example embodiment, the optical system is part of a two-photon polymerization (TPP) 3D printing system that includes a laser scanner positioned to receive a laser beam from an illumination source, and to direct the laser beam to the optical system. In yet another example embodiment, the optical system further includes a relay lens system positioned to receive a collimated laser beam from the laser scanner, wherein the relay lens system is configured to relay an aperture of the laser scanner to a pupil of each of the plurality of objectives. In still another example embodiment, an optical axis associated with an output beam of the laser scanner is rotated about 90 degrees with respect to an optical axis of each of the plurality of objectives.

[0022] In another example embodiment, at least one of the beamsplitters is configured to split an optical beam that is incident thereon into even optical beams that are produced at the output of the beamsplitter. In some example embodiments, each of the plurality of objectives has a field of view that is larger than 1.5 mm and a numerical aperture (NA) that is larger than 1.0. In some example embodiments, each of the plurality of objectives has a field of view that is larger than 2.0 mm and an NA that is larger than 0.8. In some example embodiments, each of the plurality of objectives has a field of view that is larger than 2.0 mm and an NA that is larger than 1.0. In some example embodiments, each of the plurality of objectives has a field of view that is larger than 3.0 mm and an NA that is larger than 0.8. In some example embodiments, each of the plurality of objectives has a field of view that is larger than 5.0 mm and an NA that is larger than 0.6.

[0023] Only a few implementations and examples are described and other implementations, enhancements and variations can be made based on what is described and illustrated in this patent document.

Claims

CLAIMS1. An optical system for three-dimensional (3D) laser printing, comprising: one or more beamsplitters configured to receive a collimated optical laser beam and to produce a plurality of optical beams; and a plurality of objectives, each positioned to receive one of the plurality of optical beams, and to focus the received optical beam onto a focal plane that is shared by all of the plurality of objectives, wherein the focal plane coincides with a position of 3D printable material, wherein upon illumination of the 3D printable material by the beams received from the plurality of objectives a plurality of 3D-printed objects are simultaneously generated.

2. The optical system of claim 1, wherein each beamsplitter is configured to evenly divide an intensity of an optical beam that is incident thereon, and each of the plurality of objectives is identical to any other of the plurality of objectives to allow simultaneous generation the plurality of substantially identical 3D-printed objects.

3. The optical system of claim 1, wherein the 3D-pritinable material is coupled to a moveable stage that allows the 3D-printable material to move in X-, Y- or Z-directions.

4. The optical system of claim 1 , comprising a single tray that accommodates the 3D printable material corresponding to the plurality of objectives, wherein the single tray is configured to move in X-, Y- or Z-directions.

5. The optical system of claim 1, comprising a plurality of trays, each tray configured to accommodate the 3D printable material corresponding to one of the plurality of objectives, wherein each of the plurality of trays is configured to move in X-, Y- or Z-directions.

6. The optical system of claim 1, wherein at least one of the plurality objectives provides a different magnification than another of the plurality of objectives to allow simultaneous generationof 3D-pinted objects, wherein at least one of the plurality of 3D-printed objects has a different size compared to at least another one of the 3D-printed objects.

7. The optical system of claim 1, wherein the optical system is part of a two-photon polymerization (TPP) 3D printing system, and wherein each of the plurality of objectives is configured to compensate for aberrations over only a range of wavelengths corresponding to laser illumination associated with the TPP 3D printing system.

8. The optical system of claim 7, wherein the laser illumination is provided by a femtosecond laser with a central wavelength in a range 775 nm to 785 nm.

9. The optical system of claim 7, wherein the laser illumination is provided by a femtosecond laser with a central wavelength in a range 520 nm to 535 nm.

10. The optical system of claim 7, wherein the laser illumination is provided by a femtosecond laser with a central wavelength in a range 1,000 nm to 1, 100 nm.

11. The optical system of claim 1 , wherein the plurality of obj ectives consists of four obj ectives.

12. The optical system of claim 1, wherein the plurality of objectives consists of eight objectives.

13. The optical system of claim 1, wherein the optical system is part of a two-photon polymerization (TPP) 3D printing system that includes a laser scanner positioned to receive a laser beam from an illumination source, and to direct the laser beam to the optical system.

14. The optical system of claim 13, further comprising a relay lens system positioned to receive a collimated laser beam from the laser scanner, wherein the relay lens system is configured to relay an aperture of the laser scanner to a pupil of each of the plurality of objectives.

15. The optical system of claim 13, wherein an optical axis associated with an output beam of the laser scanner is rotated about 90 degrees with respect to an optical axis of each of the plurality of objectives.

16. The optical system of claim 1, wherein at least one of the beamsplitters is configured to split an optical beam that is incident thereon into even optical beams that are produced at the output of the beamsplitter.

17. The optical system of any of claims 1-16, wherein each of the plurality of objectives has a field of view that is larger than 1.5 mm and a numerical aperture (NA) that is larger than 1.0.

18. The optical system of any of claims 1-16, wherein each of the plurality of objectives has a field of view that is larger than 2.0 mm and an NA that is larger than 0.8.

19. The optical system of any of claims 1-16, wherein each of the plurality of objectives has a field of view that is larger than 2.0 mm and an NA that is larger than 1.0.

20. The optical system of any of claims 1-16, wherein each of the plurality of objectives has a field of view that is larger than 3.0 mm and an NA that is larger than 0.8.

21. The optical system of any of claims 1-16, wherein each of the plurality of objectives has a field of view that is larger than 5.0 mm and an NA that is larger than 0.6.

22. A method for producing a plurality of 3D-printed objects, comprising: providing laser illumination to a scanner configured to direct the laser illumination to an optical printing head that includes: one or more beamsplitters configured to receive the laser illumination and to produce a plurality of optical beams, anda plurality of objectives, each positioned to receive one of the plurality of optical beams, and to focus the received optical beam onto a focal plane that is shared by all of the plurality of objectives, wherein the focal plane coincides with a position of 3D printable material to allow 3D printing of one layer of each of the plurality of 3D objects, and moving a position of the 3D printable material to allow printing of one or more additional layers of each of the plurality of 3D objects.

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