Three-dimensional printed glass elements with controllable local transmission and methods for producing the same

Abstract

Three-dimensional (3D) printed structures and methods for 3D-printed glass or ceramic structures with controlled transparency levels are described. One example method for 3D printing of a glass structure includes illuminating a 3D print medium with a laser light at a laser power and a laser scan rate in a laser-based polymerization printing process to produce an intermediate 3D printed structure. The method includes applying heat at a temperature and at a heat rate to the intermediate 3D printed structure as part of a pyrolysis process, and stopping the application of heat to produce a monolithic 3D printed glass structure having multiple sections with different transparency levels. The different transparency levels of the multiple sections are obtained by varying one or more of: the laser power or the laser scan rate during the printing process, a thickness of the 3D print medium, or the temperature or the heat rate.

Description

PCT Patent Application044974.8139.WOOOTHREE-DIMENSIONAL PRINTED GLASS ELEMENTS WITH CONTROLLABLE LOCAL TRANSMISSION AND METHODS FOR PRODUCING THE SAMESTATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0001] This invention was made with Government support under Grant No. CA268190 awarded by the National Institute of Health. The Government has certain rights in the invention.CROSS-REFERENCE TO RELATED APPLICATION(S)

[0002] This application claims priority7to the provisional application with serial number 63 / 682,296 titled “THREE-DIMENSIONAL PRINTED GLASS ELEMENTS WITH CONTROLLABLE LOCAL TRANSMISSION AND METHODS FOR PRODUCING THE SAME,” filed August 12, 2024. The entire contents of the above noted provisional application are incorporated by reference as part of the disclosure of this document.TECHNICAL FIELD

[0003] The technology7described in this patent document relates to methods, devices and systems for three-dimensional printing of glass or ceramic structures.BACKGROUND

[0004] Glass is a ubiquitous material in modem society, renowned for its exceptional physical and chemical properties. Its versatility and durability have led to its widespread use in numerous applications, including packaging, architecture, energy technologies, electronic devices, medicine, data transmission devices, optics, and photonics. These diverse fields benefit from the unique characteristics of glass, such as its transparency, strength, and resistance to chemical reactions. However, compared to metals and polymers, glass is challenging to process, particularly when it comes to creating complex and precise geometries. Consequently, the additive manufacturing of glass has become a critical topic in the modem manufacturing industry. Therefore, there is a need for improved manufacturing of glass and other materials using additive manufacturing techniques.SUMMARY

[0005] The disclosed embodiments, among other features and benefits, describe methods and systems that utilize a laser-based polymerization printing (e.g., two-photon polymerization (TPP)) a carbon-containing precursor material (e.g. polymeric silsesquioxane (PSQ)) to enable three-dimensional (3D) printing of inorganic glass / ceramic micro-objects with controlled transparency.

[0006] One example method for 3D printing of a glass structure includes illuminating a 3D1044974.8139. WOOO\183083524.1PCT Patent Application044974.8139.WOOO print medium with a laser light at a laser power and a laser scan rate as part of a two-photon polymerization (TPP) printing process to produce an intermediate 3D printed structure, wherein one or both of the laser power and the laser scan rate are adjustable during the TPP printing process. The method further includes applying heat at a temperature and according to a heat rate to the intermediate 3D printed structure as part of a pyrolysis process, wherein one or both of the temperature and heat rate are adjustable, and stopping the application of heat to produce a monolithic 3D printed glass structure that includes multiple sections with different transparency levels. The different transparency levels of the multiple sections are obtained by varying one or more of: the laser power or the laser scan rate during the TPP printing process, a thickness of the 3D print medium, or the temperature or the heat rate.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 illustrates a 3D-printed object and how various transparency levels can be achieved in accordance with some example embodiments.

[0008] FIG. 2 illustrates an example 3D-printed cylinder structure and associated characteristics in accordance with some example embodiments.

[0009] FIG. 3 illustrates example 3D-printed structures and associated characteristics for different laser power and laser scanning parameters in accordance with some example embodiments.

[0010] FIG. 4 illustrates several example structures that are 3D printed in accordance with some example embodiments.

[0011] FIG. 5 illustrated example 3D-printed structures including multiple transparent optical elements and at least one opaque structure in accordance with some example embodiments.

[0012] FIG. 6 illustrates an example optical system, its associated ray diagram and images of the 3D printed structure in accordance with some example embodiments.

[0013] FIG. 7 illustrates a set of operations that can be carried out for three-dimensional (3D) printing of a glass structure in accordance with an example embodiment.DETAILED DESCRIPTION

[0014] Despite its advantages, current three-dimensional (3D) printing techniques for glass elements suffer from limited control over their transparency. This limitation restricts the applications in industries requiring accurate optical resistance or precise light intensity control, such as optics and photon systems, environmental and biological sensors, UV absorbers, thermal isolators, and neutral-density filters, or even printing ornamental objects with differing2044974.8139. WOOO\183083524.1PCT Patent Application044974.8139.WOOO transparency levels. Tailored transparency in glass not only broadens its application range but also enhances its reliability and performance. For instance, imaging systems must use apertures, stops, and intensity filters to avoid stray light and modulate light power, achieving higher optical imaging performance, as seen in endoscopes.

[0015] The transparency of glass can be influenced through the use of optical coatings or the incorporation of transition metal ions. This process is highly dependent on the amounts of additives and the thickness of the structure to ensure sufficient light absorption. These requirements necessitate complex thermal treatment strategies, which increase production costs and reduce precision control, especially for nano- and micro-scale features. Furthermore, the addition of inorganic metal ions complicates the direct laser writing (DLW) process bydecreasing light penetration. The concentration of metal ions in glass 3D printing materials is also typically limited due to the poor solubility of metal salts in printing resins.

[0016] Controlling glass purity without additives is one approach to achieve tailored transparency in high-precision 3D printed glass. While powder-based printing materials using high-purity silica nanopowder are difficult to tune due to SiO2's stable properties, silsesquioxane-based materials offer more flexibility owing to their carbon-rich nature. The process to fabricate glass from silsesquioxane-based materials typically involves photopolymerization printing, washing, and high-temperature treatment. During printing, carbon bonds form through cross-linking to create 3D shapes. Subsequent pyrolysis in air usually cleaves and oxidizes hydrocarbons bonded to Si atoms, leaving only Si and O. However, incomplete oxidation results in residual carbon species, which can cause a black appearance. By controlling the content of unoxidized carbon species during pyrolysis, it is possible to produce glass or ceramics with colored appearances and controlled transparency.

[0017] The disclosed embodiments relate to methods and corresponding systems that utilize two-photon polymerization (TPP) and polymeric silsesquioxane (PSQ) to 3D print inorganic glass / ceramic micro-objects with controlled transparency. The transparency of these objects can be regulated through multiple mechanisms: by adjusting the sample thickness and pyrolysis conditions, and by pre-programming different regions of the object in-situ during the printing process. This in-situ control is achieved by tuning the laser power and scanning speed, offering flexibility in creating single glass / ceramic objects with varying transparency regions, which is challenging for glass micro-objects and cannot be achieved in prior techniques. This approach expands the capabilities of 3D printing technology for producing complex glass and ceramic structures with tailored optical properties. In the description that follows, example 3D printed3044974.8139. WOOO\183083524.1PCT Patent Application044974.8139.WOOO elements are described, including various optical elements that can be used in optical instruments, such as imaging devices, illumination systems and the like. However, it is understood that the disclosed 3D printed objects can be used in other systems and for other applications that can benefit from having glass elements with differing levels of transparency.Example Implementation

[0018] In the following example, we 3D-printed an object and illustrated how various transparency levels can be achieved. In this example implementation, the material for producing the 3D printed optical element was based on polymeric silsesquioxane (PSQ). Panel A of FIG. 1 illustrates the structure of polymeric silsesquioxane. Direct laser writing (DLW) based on two- photon polymerization (TPP) is illustrated in panel B of FIG. 1. DLW can be utilized to achieve sub-wavelength resolution spatial control for complex micro geometries. Panel C shows the printed structure. After printing and washing, the printed objects were pyrolyzed in air at 650°C to reach inorganic status. The transparency of the final glass is influenced by the ease with which oxygen can penetrate and react with the organic components embedded in the cured PSQ. The transparency performances under different degrees of oxidation are shown in panels D-F of FIG. 1.

[0019] Before we printed the glass optical structures with various transparencies, we explored whether the PSQ can reach different transparency levels after pyrolysis in air by controlling the oxidation degree. Two batches of free stand thin films were prepared: thin films pyrolyzed in air and thin films pyrolyzed in a high-vacuum environment, which limits the oxidation of hydrocarbons in the cured PSQ material. Post-pyrolysis, the samples treated in air were colorless and transparent, while those treated under vacuum were black and exhibited ery low' transparency to visible light. Solid state nuclear magnetic resonance (NMR) imaging was used to demonstrate that the dark or brown tint is primarily caused by the unoxidized carbon composition after pyrolysis. The29Si NMR spectrum revealed that the primary structures of Si in the transparent samples w ere Q3 and Q4 types, w ith a minor presence of Q2 type. Panel G of FIG. 1, shows29Si solid state NMR of cured PSQ pyrolyzed under air atmosphere. Notably, no T-type peaks were observed, indicating that almost all carbons were cleaved from the Si atoms.

[0020] Additionally, the13C NMR spectrum showed no aromatic species remaining in the structure, suggesting a high level of oxidation was achieved, as illustrated in panel I,13C solid state NMR of cured PSQ pyrolyzed under air atmosphere. Conversely, the samples pyrolyzed under vacuum displayed T-type peaks from -45 ppm to -80 ppm (as illustrated in panel H of FIG.1, illustrating cured PSQ pyrolyzed under vacuum), indicating that some C atoms were still4044974.8139. WOOO\183083524.1PCT Patent Application044974.8139.WOOO connected to Si atoms, likely due to incomplete oxidation. Furthermore, the broad peak (-105 ppm - 150 ppm) in the13C NMR spectrum (see panel J of FIG. 1 , illustrating13C NMR for cured PSQ pyrolyzed under vacuum) confirmed the presence of aromatic species in the black samples, which is common in pyrolysis when oxidation is incomplete.

[0021] We then investigated whether the oxidation degree (and thus transparency) of the pyrolyzed printed parts could be adjusted after they are pyrolyzed in air. The most straightforward method to control oxidation is by manipulating sample thickness, as thicker samples impede oxygen penetration and complete oxidation. Panels K and L in FIG. 1 illustrate this effect. Panel K showcases a ring tower with varying wall thicknesses (with wall thickness decreasing from left to right), clearly demonstrating transparency variations. Panel L presents a ball-and-stick model where balls with a diameter of approximately 50 pm appear entirely black, while sticks with a thickness of 10 pm are transparent. These results indicate that even when pyrolyzed in air, printed parts can achieve low transparency because the cured PSQ is sufficiently dense to prevent oxygen permeation in thicker sections.

[0022] With that, we further explored how the transparency of the final glass can be finely regulated by tuning various fabrication and process conditions. To investigate this, we designed and printed a testing cylinder structure. Panel A in FIG. 2 illustrates an example cylinder structure, the thermal treatment process and the final glass with different transparency. Panel D shows an SEM image of an example 3D printed structure (scale bar: 50 pm). As shown in panel A, the testing structure included a bottom and a top supporting rings and pillars to create distances between the testing area and the quartz substrate, thereby avoiding interference that could affect the final transparency. The testing area included a cylinder with a diameter of 125 pm, produced in three different thicknesses (16 pm, 17 pm, and 18 pm). For each thickness, we applied various heating rates during pyrolysis, as shown in panels B and E. We also discovered that the final transparency could be tuned by adjusting the laser power and scanning speed during printing. Consequently, for each thickness and heating rate combination, we further applied six different laser pulse energies and scanning speeds (see panel C in FIG. 2), resulting in 324 unique transparency conditions across all parameter combinations. This comprehensive approach allowed for a thorough investigation of transparency control.

[0023] In an example set up, the printing system included a 780 nm fiber laser with 150 fs pulse, at 77MHz repetition rate, and a maximum power of 130 mW. The full-width half maximum (FHWM) of the beam was 10 mm, 90% filling the objective (NA=1.3). The testing samples in panel B of FIG. 2 were printed at the laser powers of 34m W, 37mW, 40mW, 43mW,5044974.8139. WOOOM 83083524.1PCT Patent Application044974.8139.WOOO46mW, and 49mW with 55440 Lim / s scan rate on the quartz substrate. After printing, the uncured resin was washed using PGMEA and ethanol and dried before thermal treatment. In our case for p cylinder samples' printing, the intensity per pulse, ( / „ = — ), defined by the fluence (F„) and tPpulse duration (tp) were ~(1.01, 0.95,0.89,0.83,0.76,0.7 )TWcm~2with 193 pulses overlapped. Energy deposition depth is the skin depth at the conditions of exposure lp= In printing resolution, the axial printing resolution is around 3.5 times that of the lateral printing resolution. The printed parts were heated in a furnace to 650 °C with three different heating strategies in air. All samples were initially heated to 300 °C at a consistent rate of 6.875 °C / min. Heating rate 1 to 3 were heated to 650 °C at rates ranging from 5.470 °C / min, 5 °C / min to 4.118 °C / min respectively (see panel E in FIG. 2). The sample was then kept at 650 °C for 2 hours and gradually cooled down to room temperature. After cool-down, final structures were obtained. No additional processing was performed after pyrolysis.

[0024] As expected, thicker cylinders are more likely to yield glass with brown or dark coloration, given the same printing power, scanning speed, and pyrolysis heating rate. Notably, transparency was extremely sensitive to thickness differences, allowing for efficient adjustment within a range of 1 to 2 micrometers. Interestingly, the heating rate during pyrolysis also significantly influences the degree of hydrocarbon oxidation. Panel B illustrates that samples heated at higher rates are more prone to turning brown and black, which supports that higher heating rates can cause the object's shell to pyrolyze more rapidly compared to the oxygen permeation rate. Once a condensed silica shell forms, it inhibits further oxygen permeation, halting oxidation within the object and resulting in a colored appearance. Conversely, slower heating rates promote a more homogeneous pyrolysis process throughout the object, facilitating complete oxidation.

[0025] A powerful process for manipulating transparency is adjusting the laser power and scanning speed during printing. Panel F in FIG. 2 illustrates the normalized transparency performances as a function of laser power and scanning speed. Although these parameters shouldn't alter the chemical structure, as they all lead to photo-induced free radical polymerization, they significantly affect the monomer conversion (crosslinking degree) of the final printed objects. This, in turn, influences the ease of oxidation and thus transparency in two ways, as high power and low scanning speed result in higher monomer conversion: 1) higher conversion may lead to slightly denser material after the washing process, as less monomer is washed out from the surface, and 2) higher crosslinking degree of acrylates usually leads to a6044974.8139. WOOO\183083524.1PCT Patent Application044974.8139.WOOO higher degradation temperature, making complete oxidation more difficult.

[0026] To demonstrate the feasibility of manipulating transparency by changing printing parameters, we achieved local control over the transparency of pyrolyzed glass by varying the laser power and scanning speed during printing. All cylinders are visually identical right after printing. Panel D in FIG. 2 illustrates a printed glass cylinder with a pre-pyrolysis thickness of 16 pm, pyrolyzed at "Heating rate 1" (see panel 2E). To normalize transparency measurements, we used the captured light intensity of a structure-free area on the same quartz substrate as a reference (see panel D). The resulting transmittance is depicted in panel F, showing that transmission decreases with increased laser pulse energy' and decreased laser scanning speed. For the cylinder with a pre-pyrolysis thickness of 16 pm, the lowest transmitted intensity was approximately 4% (laser power of 49 mW, scanning speed of 28.8 mm / s). This strategy allows us to pre-program the transparency during the printing in different regions of one object even with the same thickness. It is important to note that higher laser power and slower scanning speed increase the size of polymer features, potentially leading to greater thickness that can also affect transparency. To ensure consistent thickness across test cylinders, we adjusted the z-axis travel distance for compensation, allowing independent control of both thickness and monomer conversion.

[0027] Raman spectroscopy was employed to demonstrate monomer conversion differences between cylinders printed with varying parameters. Nine cylinders of identical thickness (16 pm, confirmed by white light interferometry) were printed using different laser power and laser scanning parameters, as shown in panels A and E in FIG. 3. In particular, panel E illustrates the surface profiles of the tested samples in panel A tested by Zygo Newview 8300 white-light interferometer. All surface peak-to-valley values were from 14.22 pm to 14.45 pm. The thickness of each cylinder plate is 16 pm. The height above the supporting ring 2 top-surface (see panel A in FIG. 2) is 14 pm thickness, the height below the supporting ring 2 top-surface is2 pm. Panel B in FIG. 3 show s a zoomed-in view- of section of panel A.

[0028] Raman microspectroscopy quantitatively measured the vibration of unreacted C=C bonds (1639 cm’1) and the constant C=O bonds (cm’1), as illustrated in panel C in FIG. 3. We used the area ratio between C=C and C=O to represent the relative unreacted monomer (the low er the value, the higher the monomer conversion), as the carbonyl group remains unchanged during polymerization, except for a negligible amount from the initiator (<1%). Panel D in FIG.3 demonstrates that as laser power increases and scanning speed decreases, the relative unreacted monomer decreases, reaching a minimum value of 0.714 during the test. This corresponds to7044974.8139. WOOO\183083524.1PCT Patent Application044974.8139.WOOO the highest power of 49 mW and the slowest speed of 28.8 mm / s. In panel D, groups A, B, and C refer to laser power of 34 mW, 43 mW. and 49 mW, respectively. Groups I, II, and III refer to scanning speeds of 28.8 mm / s, 43.2 mm / s, and 86.4 mm / s, respectively. Notably, cylinder B- II in panel D shows a slightly higher monomer conversion than B-I, likely due to laser power fluctuations during the experiment, which proved difficult to completely eliminate with our experimental setup. Post-pyrolysis observations revealed that cylinder B-II exhibited a darker appearance compared to B-I. aligning with the relative conversion results, as illustrated in panel F in FIG. 3. In particular, panel F shows the relative transparency performances of the samples of panel A after pyrolysis. This further demonstrates that the final transparency is directly linked to the monomer conversion.

[0029] It is important to note that variations in oxidation degree not only affect transparency but also lead to differences in shrinkage values due to varying amounts of carbon removed during pyrolysis. For the samples studied in panel C of FIG. 2, the shrinkage ranges from 29% to 32.4%, corresponding to transparency levels from approximately 4% to 95%.

[0030] The disclosed embodiments illustrate that the transparency of printed micro-objects can be flexibly adjusted, creating, for example, either identical shapes with varying transparencies or complex structures with multiple regions of different transparencies. The transparencies can change abruptly from one section to another section (or from one element to another element) in a stepwise fashion. Alternatively, the transparencies can change gradually (or monotonically) from one section or one element to another element or section. Some example 3D printed structures are shown in FIG. 4. For instance, we printed black and white swans in an embrace, demonstrating uniform transparency from head to body and distinct white flight feathers on the black sw an's wings, as illustrate in panel A of FIG. 4. We also printed binary fringes, a checkerboard pattern, and a black aperture on a clear plate, showcasing predesigned transparency variations through adjustments in feature thickness or conversion degree, as shown in panel B of FIG. 4.

[0031] Our printed structures performed well without cracks. Panels C and D in FIG. 4 illustrate printed tubes with external diameters (ED) of 220 pm and 155 pm. respectively, both with a wall diameter (ID) of 17 pm, subjected to "Heating rate 1" thermal treatment (see discussion in connection with FIG. 2). Beyond the color (transparency) differences observed under microscopic imaging, SEM analysis revealed ED differences of the regions with higher and lower transparency. The black and yellow tube (see panel C in FIG. 4) showed an ED difference of approximately 1.2% ± 0. 1 %, while the black and white tube (see panel D) exhibited8044974.8139. WOOOM 83083524.1PCT Patent Application044974.8139.WOOO an ED difference of about 3.1% ± 0.2%. These differences, primarily caused by varying shrinkage, may be compensated for in the original design.

[0032] Another aspect of the disclosed embodiments relates to producing one or more optical structures with varying transparencies to suppress or control stray light in an optical system. Panels E-J in FIG. 4 illustrate example structures for stray light suppression in micro-optical systems. Stray light significantly reduces contrast and signal-to-noise ratio in imaging systems, posing challenges in fields such as astronomy, medical testing, and electronic equipment. Current solutions involve adding special components like light shields and apertures, but these require additional assembly and lack efficiency, especially for glass micro-optics. Using our transparency-controlled glass 3D printing technique, we directly fabricated integrated optical components containing lenses, apertures, stop rings, and mounts. Panel E in FIG. 4 shows a 3 / 4 doublet and singlet imaging glass optical system (Diameter: 200 pm) with visible light images from top-view and SEM images from side-view, demonstrating clear glass lenses and dark opaque parts. Panels F and G display the complete optical system, featuring a thin gap on the side to facilitate washing out of uncured liquid material after printing. As illustrated in panels, H, I and J, a profile comparison of two intensity cuts through a line pair of the USAF test target for the singlet lens, with (panel I) and without (panel H) a black aperture, revealed an enhancement in the Michelson contrast (CM = (Imax - Imin) / (Imax + Imin)) by more than a factor of 3.5. Notably, the area identified by the rectangles in panels H and I were used for the contrast comparison. In panel J. the curve with the smaller contrast is associated with the rectangular area of panel H, and the curve with the larger contrast is associated with the rectangular area of panel I.

[0033] This demonstrates the effectiveness of our technique in achieving desired transparencies in 3D-printed glass components including, but not limited to, lenses, prisms, gratings, parallel plates, filters, masks and combinations thereof, that comprise multitransparency micro 3D architectures, thus enhancing their application in various fields requiring specific optical properties.

[0034] In one example application, using the disclosed techniques, optical components and / or systems can be 3D printed to include baffles, occlusion masks that are integrated as part a monolithic optical system to provide stray light control and / or suppression. In one example, a 3D printed lens includes an outer annulus that is less transparent than the central portion. In another example, stray light control can be achieved by printing opaque outer tube / housing of the optical system, as illustrated in FIG. 5. Notably, the left side of FIG. 5 shows an example9044974.8139. WOOO\183083524.1PCT Patent Application044974.8139.WOOO structure that includes multiple lenses, while panels A and C show structure with a transparent tube and with an absorptive tube, respectively. Panels B and D illustrate ray diagrams associated with the structures in panels B and C, respectively. Similarly, in FIG. 6, a rendering of an optical system and its associated ray diagram are shown in panels A and B, while panels C and D illustrate actual perspective view' and top-view images of the 3D printed structure, respectively, illustrating a clear central section and opaque peripheral sections.

[0035] It is evident that by controlling the oxidation degree of printed PSQ during pyrolysis, a transparency-on-demand glass 3D printing technique can be implemented. The disclosed embodiments enable the direct manufacturing of multi-transparency micro 3D architectures without the need for any additives and other processes. According to some example embodiments, laser-induced conversion adjustments and thickness variations are used during the printing process, as well as the heating rate during the pyrolysis, to manage the transparency distribution of the glass, enhancing the functionality and versatility of the printed structures. Accordingly, the scope of light-material interaction dimensions can be increased, thus paving the way for more complex and diverse applications.

[0036] One aspect of the disclosed embodiments relates to a method for producing a glass or ceramic structure having spatially varying optical transmission. The method includes (a) forming a three-dimensional structure from a carbon-containing glass precursor material by a laser-induced polymerization printing process; and (b) converting the precursor to an inorganic glass or ceramic in a heat treatment process, wherein one or more process parameters during the forming step and / or during the heat treatment step are varied according to a predetermined spatial pattern to produce regions of differing optical transmission. In another aspect, a three- dimensional glass or ceramic structure includes a body form from a single material. The structure includes a plurality of regions within the body having differing optical transmission levels, wherein the differing optical transmission levels correspond to a predetermined spatial pattern produced by varying one or more process parameters during fabrication and / or postprocessing. Another aspect of the disclosed embodiments relates to system for producing a three-dimensional glass or ceramic structure having spatially varying optical transmission; the system includes a laser-based three-dimensional printing apparatus configured to fabricate a structure from a carbon-containing glass precursor material, a control unit configured to vary one or more printing parameters according to a spatial transparency map, and a heat treatment apparatus configured to convert the precursor to an inorganic glass or ceramic, wherein one or more heating parameters are varied according to the spatial transparency map. In another aspect10044974.8139. WOOO\183083524.1PCT Patent Application044974.8139.WOOO a glass or ceramic structure is described that includes a plurality of regions of a single material, each region having an optical transmission level that differs from at least one other region. The plurality of regions define a predetermined transparency pattern configured for at least one of stray light suppression, light intensity modulation, optical filtering, or other optical effect.

[0037] FIG. 7 illustrates a set of operations that can be carried out for three-dimensional (3D) printing of a glass structure in accordance with an example embodiment. At 702, a 3D print medium is illuminated with a laser light at a laser power and a laser scan rate as part of a laser-based polymerization printing process to produce an intermediate 3D printed structure. For example, the printing process can be a two-photon polymerization (TPP) printing process. One or both of the laser power and the laser scan rate are adjustable during the TPP printing process. At 704, heat is applied at a temperature and according to a heat rate to the intermediate 3D printed structure as part of a pyrolysis process, wherein one or both of the temperature and heat rate are adjustable. At 706, the application of heat is stopped to produce a monolithic 3D printed glass structure that includes multiple sections with different transparency levels. The different transparency levels of the multiple sections are obtained by varying one or more of: the laser power or the laser scan rate during the printing process, a thickness of the 3D print medium, or the temperature or the heat rate.

[0038] In one example embodiment, the different transparency levels of the multiple sections are controlled based on differing pre-assigned thicknesses of the multiple sections of the 3D print medium. In another example embodiment, the pre-assigned thicknesses are selected to account for variations of the laser power, the laser scan rate, the temperature or the heat rate in producing a desired transparency level for one or more of the multiple sections. In yet another example embodiment, the pre-assigned thicknesses are selected to compensate for shrinkage of one or more sections of the monolithic 3D printed glass structure due to variations in the laser power, the laser scan rate, the temperature or the heat rate. In still another example embodiment, the 3D printed medium is a carbon-containing glass precursor. For example, the 3D print medium can be polymeric silsesquioxane (PSQ). According in another example embodiment, the monolithic 3D printed glass structure comprises a lens, a prism, a grating, a parallel plate, a filter, a baffle, a mask or a combination thereof.

[0039] In some example embodiments, the method for 3D printing of the glass structure includes one or more of the following operations: (a) changing the laser power from a first power level to a second power level as the laser moves over from a first section of the 3D print medium to a second section of the 3D print medium to effectuate a different transparency level for the11044974.8139. WOOO\183083524.1PCT Patent Application044974.8139.WOOO first section compared to the second section in the monolithic 3D printed glass structure, (b) changing the laser scan rate from a first value, when the laser is illuminating a first section of the 3D print medium, to a second value, when the laser is illuminating a second section of the 3D print medium, to effectuate a different transparency level for the first section compared to the second section in the monolithic 3D printed glass structure, (c) applying heat at a first temperature to the intermediate 3D printed structure that effectuates a different transparency level for the one or more sections of the monolithic 3D printed glass structure compared to when heat is applied at a second temperature, or (d) applying the heat at a first heat rate to the intermediate 3D printed structure that effectuates a different transparency level for the one or more sections of the monolithic 3D printed glass structure compared to when heat is applied at a second heat rate. In one example embodiment, in operation (a), the first power level is larger than the second power level, resulting in a higher transparency level of the first section compared to the second section. In another example embodiment, in operation (b), the first value is larger than the second value, resulting in a lower transparency level of the first section compared to the second section. In still another example embodiment, in operation (c), the first temperature is higher than the second temperature, resulting in a higher transparency level that can be achieved by application of the first temperature compared to the second temperature. In yet another example, embodiment, in operation (d), the first heat rate is higher than the second heat rate, resulting in a lower transparency level that can be achieved by application of the first heat rate compared to the second heat temperature.

[0040] Another aspect of the disclosed technology relates to a monolithic 3D-printed glass structure that includes a plurality of sections structured to have varying transparency levels based on one or more parameters of a laser-based polymerization 3D printing or pyrolysis process, or pre-assigned thicknesses of the plurality of sections. A first section of the plurality of sections has a first transparency level and a second section of the plurality of sections has a second transparency level that is different from the first transparency level. The monolithic 3D-printed glass structure has one or more dimensions that is less than or equal 50 microns, and the monolithic 3D-printed glass structure is made from same material.

[0041] In one example embodiment, the first section and the second section have the same thickness. In another example embodiment, the monolithic 3D-printed glass structure incudes one or more of: a lens, a prism, a grating, a parallel plate, a filter, a baffle, a mask or a combination thereof, all formed as part of the monolithic 3D-printed glass structure. In yet another example embodiment, the monolithic 3D-printed glass structure includes one or more12044974.8139. WOOOM 83083524.1PCT Patent Application044974.8139.WOOO optical components, and further includes a housing to accommodate the one or more optical components, wherein the one or more optical components and the housing are formed as part of the monolithic 3D-printed glass structure and include at least one section that is opaque and at least one section that is substantially transparent. In still another example embodiment, the housing is entirely opaque and a central section of each of the one or more optical components is substantially transparent. In another example embodiment, a peripheral section of at least one of the one or more optical components is opaque.

[0042] In one example embodiment, transparency levels of two or more adjacent sections of the plurality of sections monotonically change across the two or more adjacent sections. In another example embodiment, transparency levels of two or more adjacent sections of the plurality of sections abruptly change at a boundary of the two or more adjacent sections. In still another example embodiment, the transparency levels abruptly change at the boundary of the two or more adjacent sections from a substantially fully transparent level to a fully opaque level. In yet another example embodiment, the monolithic 3D-printed glass structure includes multiple same-sized optical components, wherein each of the multiple same-sized optical components has a different transparency level compared to another optical component among the multiple samesized optical components.

[0043] One example embodiment relates to a system for producing a three-dimensional glass or ceramic structure having spatially varying optical transmission. The system includes a laserbased three-dimensional printing apparatus configured to fabricate an intermediate 3D printed structure from a carbon-containing glass precursor material. The system also includes a heat treatment apparatus configured to convert the carbon-containing glass precursor material to an inorganic glass or ceramic, and a processor and a memory comprising instructions stored thereon. The instructions upon execution by the processor configure the processor to vary one or more printing or heating parameters according to a spatial transparency map. In one example embodiment, the laser-based three-dimensional printing apparatus is a two-photon polymerization printing (TPP) apparatus. In another example embodiment, the one or more printing or heating parameters includes a laser power, a laser scan rate, a temperature associated with the heat treatment apparatus or the heat rate associated with the heat treatment apparatus.

[0044] While this patent document contains many specifics, these should not be construed as limitations on the scope of any invention or of what may be claimed, but rather as descriptions of features that may be specific to particular embodiments of particular inventions. Certain features that are described in this patent document in the context of separate embodiments can13044974.8139. WOOO\183083524.1PCT Patent Application044974.8139.WOOO also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

[0045] Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Moreover, the separation of various system components in the embodiments described in this patent document should not be understood as requiring such separation in all embodiments.

[0046] It is understood that the various disclosed embodiments may be implemented individually, or collectively, in devices comprised of various optical components, electronics hardware and / or software modules and components. These devices may be used to control the operation of various devices and processes, such as the 3D printing process, application of heat and illumination sources. These devices, for example, may comprise a processor, a memory unit, an interface that are communicatively connected to each other, and may range from desktop and / or laptop computers, to mobile devices and the like. The processor and / or controller can perform various disclosed operations based on execution of program code that is stored on a storage medium. The processor and / or controller can, for example, be in communication with at least one memory and with at least one communication unit that enables the exchange of data and information, directly or indirectly, through the communication link with other entities, devices and networks. The communication unit may provide wired and / or wireless communication capabilities in accordance with one or more communication protocols, and therefore it may comprise the proper transmitter / receiver antennas, circuitry and ports, as well as the encoding / decoding capabilities that may be necessary for proper transmission and / or reception of data and other information. For example, the processor may be configured to receive electrical signals or information from the disclosed sensors (e.g., CMOS sensors), and to process the received information to produce images or other information of interest.

[0047] Various information and data processing operations described herein may be implemented in one embodiment by a computer program product, embodied in a computer-14044974.8139. WOOO\183083524.1PCT Patent Application044974.8139.WOOO readable medium, including computer-executable instructions, such as program code, executed by computers in networked environments. A computer-readable medium may include removable and non-removable storage devices including, but not limited to, Read Only Memory (ROM), Random Access Memory (RAM), compact discs (CDs), digital versatile discs (DVD), etc. Therefore, the computer-readable media that is described in the present application comprises non-transitory storage media. Generally, program modules may include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract datatypes. Computer-executable instructions, associated data structures, and program modules represent examples of program code for executing steps of the methods disclosed herein. The particular sequence of such executable instructions or associated data structures represents examples of corresponding acts for implementing the functions described in such steps or processes.

[0048] 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.15044974.8139. WOOOM 83083524.1

Claims

PCT Patent Application044974.8139.WOOOCLAIMS1. A method for three-dimensional (3D) printing of a glass structure, the method comprising: illuminating a 3D print medium with a laser light at a laser power and a laser scan rate as part of a laser-induced polymerization printing process to produce an intermediate 3D printed structure, wherein one or both of the laser power and the laser scan rate are adjustable during the printing process; applying heat at a temperature and according to a heat rate to the intermediate 3D printed structure as part of a pyrolysis process, wherein one or both of the temperature and the heat rate are adjustable; and stopping the application of heat to produce a monolithic 3D printed glass structure that includes multiple sections with different transparency levels, wherein the different transparency levels of the multiple sections are obtained by varying one or more of: the laser power or the laser scan rate during the printing process, a thickness of the 3D print medium, or the temperature or the heat rate.

2. The method of claim 1, wherein the different transparency levels of the multiple sections are controlled based on differing pre-assigned thicknesses of the multiple sections of the 3D print medium.

3. The method of claim 2, wherein the pre-assigned thicknesses are selected to account for variations of the laser power, the laser scan rate, the temperature or the heat rate in producing a desired transparency level for one or more of the multiple sections.

4. The method of claim 2, wherein the pre-assigned thicknesses are selected to compensate for shrinkage of one or more sections of the monolithic 3D printed glass structure due to variations in the laser power, the laser scan rate, the temperature or the heat rate.

5. The method of claim 1, wherein the 3D print medium is a carbon-containing glass precursor.

6. The method of claim 1, wherein the 3D print medium is polymeric silsesqui oxane (PSQ).16044974.8139. WOOO\183083524.1PCT Patent Application044974.8139.WOOO7. The method of claim 1, wherein the monolithic 3D printed glass structure comprises a lens, a prism, a grating, a parallel plate, a filter, a baffle, a mask or a combination thereof.

8. The method of claim 1, comprising one or more of the following operations:(a) changing the laser power from a first power level to a second power level as the laser moves over from a first section of the 3D print medium to a second section of the 3D print medium to effectuate a different transparency level for the first section compared to the second section in the monolithic 3D printed glass structure,(b) changing the laser scan rate from a first value, when the laser is illuminating a first section of the 3D print medium, to a second value, when the laser is illuminating a second section of the 3D print medium, to effectuate a different transparency level for the first section compared to the second section in the monolithic 3D printed glass structure,(c) applying heat at a first temperature to the intermediate 3D printed structure that effectuates a different transparency level for the one or more sections of the monolithic 3D printed glass structure compared to when heat is applied at a second temperature, or(d) applying the heat at a first heat rate to the intermediate 3D printed structure that effectuates a different transparency level for the one or more sections of the monolithic 3D printed glass structure compared to when heat is applied at a second heat rate.

9. The method of claim 8, wherein, in operation (a), the first power level is larger than the second power level, resulting in a higher transparency level of the first section compared to the second section.

10. The method of claim 8, wherein, in operation (b), the first value is larger than the second value, resulting in a lower transparency level of the first section compared to the second section.

11. The method of claim 8, wherein, in operation (c), the first temperature is higher than the second temperature, resulting in a higher transparency level that can be achieved by application of the first temperature compared to the second temperature.17044974.8139. WOOO\183083524.1PCT Patent Application044974.8139.WOOO12. The method of claim 8, wherein, in operation (d), the first heat rate is higher than the second heat rate, resulting in a lower transparency level that can be achieved by application of the first heat rate compared to the second heat temperature.

13. The method of claim 1, wherein the laser-induced polymerization printing process comprises a two-photon polymerization (TPP) printing process.

14. A monolithic 3D-printed glass structure, comprising: a plurality' of sections structured to have varying transparency levels based on one or more parameters of a laser-induced polymerization 3D printing or pyrolysis process, or preassigned thicknesses of the plurality of sections, wherein: a first section of the plurality of sections has a first transparency level and a second section of the plurality of sections has a second transparency level that is different from the first transparency level, the monolithic 3D-printed glass structure has one or more dimensions that is less than or equal 50 microns, and the monolithic 3D-printed glass structure is made from same material.

15. The monolithic 3D-printed glass structure of claim 14, wherein the first section and the second section have a same thickness.

16. The monolithic 3D-printed glass structure of claim 14, including one or more of: a lens, a prism, a grating, a parallel plate, a filter, a baffle, a mask or a combination thereof, all formed as part of the monolithic 3D-printed glass structure.

17. The monolithic 3D-printed glass structure of claim 14, including one or more optical components, and further including a housing to accommodate the one or more optical components, wherein the one or more optical components and the housing are formed as part of the monolithic 3D-printed glass structure and include at least one section that is opaque and at least one section that is substantially transparent.18044974.8139. WOOO\183083524.1PCT Patent Application044974.8139.WOOO18. The monolithic 3D-printed glass structure of claim 17, wherein the housing is entirely opaque and a central section of each of the one or more optical components is substantially transparent.

19. The monolithic 3D-printed glass structure of claim 17, wherein a peripheral section of at least one of the one or more optical components is opaque.

20. The monolithic 3D-printed glass structure of claim 14, wherein transparency levels of two or more adjacent sections of the plurality of sections monotonically change across the two or more adjacent sections.

21. The monolithic 3D-printed glass structure of claim 14, wherein transparency levels of two or more adjacent sections of the plurality of sections abruptly change at a boundary of the two or more adjacent sections.

22. The monolithic 3D-printed glass structure of claim 21, wherein the transparency levels abruptly change at the boundary of the two or more adjacent sections from a substantially fully transparent level to a fully opaque level.

23. The monolithic 3D-printed glass structure of claim 14, comprising multiple same-sized optical components, wherein each of the multiple same-sized optical components has a different transparency level compared to another optical component among the multiple samesized optical components.

24. A system for producing a three-dimensional glass or ceramic structure having spatially varying optical transmission, comprising: a laser-based three-dimensional printing apparatus configured to fabricate an intermediate 3D printed structure from a carbon-containing glass precursor material; a heat treatment apparatus configured to convert the carbon-containing glass precursor material to an inorganic glass or ceramic; and a processor and a me ory comprising instructions stored thereon, wherein the instructions upon execution by the processor configure the processor to vary one or more printing or heating parameters according to a spatial transparency map.19044974.8139. WOOO\183083524.1PCT Patent Application044974.8139.WOOO25. The system of claim 24, wherein the laser-based three-dimensional printing apparatus is a two-photon polymerization printing (TPP) apparatus.

26. The system of claim 24, wherein the one or more printing or heating parameters includes a laser power, a laser scan rate, a temperature associated with the heat treatment apparatus or the heat rate associated with the heat treatment apparatus.20044974.8139. WOOOM 83083524.1

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