Devices, systems, and methods for homogenizing electromagnetic radiation

Abstract

A system, comprising a source of electromagnetic radiation comprising an electromagnetic radiation pattern. A support configured to support a precursor of a photochemical reaction. An optical path between the source and the precursor, when present. A homogenizer of the electromagnetic radiation pattern, positioned in association with the optical path, configured to at least partially homogenize the electromagnetic radiation pattern.

Description

[0001] DEVICES, SYSTEMS, AND METHODS FOR HOMOGENIZING ELECTROMAGNETIC RADIATION

[0002] RELATED APPLICATIONS

[0003] This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application No. 63 / 703,101, filed October 3, 2024, and entitled “PROJECTOR ATTACHMENT APPARATUS FOR RANDOMIZING EMISSION,” and U.S. Provisional Patent Application No. 63 / 814,595, filed May 30, 2025, and entitled “PROJECTOR ATTACHMENT APPARATUS FOR RANDOMIZING EMISSION,” each of which is incorporated herein by reference in its entirety for all purposes.

[0004] TECHNICAL FIELD

[0005] Generally described herein are devices, systems, and methods for homogenizing electromagnetic radiation, for example in three-dimensional (3D) printing applications.

[0006] BACKGROUND

[0007] The projection and / or control of electromagnetic radiation, such as light, is often managed toward maximizing precision of the light, and, in many instances precision of pixilated, digital light. Photoinitiated reactions, such as 2D and 3D printing, lithography, and the like, have benefited from precision in projection and, where appropriate, masking of light, whether pixilated or analog. The result has been highly miniaturized, high-contrast border and edge resolution of resulting products such as micro and nanostructures, circuitry, and highly-precisely edged macroscopic printed articles.

[0008] SUMMARY

[0009] This disclosure, in many aspects, takes an approach that is different from much of the state of the art. Specifically, instead of maximizing sharp pixilation contrast in the projection of electromagnetic radiation (ER) used for initiating photochemical reactions involved in printing (including 2D or 3D printing), digital light processing (DLP), lithography, and the like, this disclosure involves at least partially homogenizing and / or blurring the distinction between pixilation in such projection, for the production of articles of higher quality than have been produced previously using these techniques. Some of these articles are optical devices.

[0010] Devices, systems, methods, software, and hardware for homogenizing electromagnetic radiation are generally described herein. The subject matter of the present disclosure involves,

[0011] #14469326vl in some cases, interrelated products, alternative solutions to a particular problem, and / or a plurality of different uses of one or more systems and / or articles.

[0012] According to certain embodiments, a system is described, the system comprising: a source of electromagnetic radiation comprising an electromagnetic radiation pattern; a support configured to support a precursor of a photochemical reaction; an optical path between the source and the precursor, when present; and a homogenizer of the electromagnetic radiation pattern, positioned in association with the optical path, configured to at least partially homogenize the electromagnetic radiation pattern.

[0013] In some embodiments, a method is described, the method comprising: at least partially homogenizing an electromagnetic radiation pattern to produce an at least partially homogenized electromagnetic radiation pattern; directing the at least partially homogenized electromagnetic radiation pattern at a precursor of a photochemical reaction; and carrying out a photochemical reaction initiated at least in part by the at least partially homogenized electromagnetic pattern.

[0014] According to some embodiments, a 3D printing system is described, the system comprising: a source of electromagnetic radiation; an optical path between the source and a projection target; a pixel generator positioned in association with the optical path, operable to generate pixelated output from respective source emissions; and a pixel shifter operable to shift respective pixelated outputs into a plurality of projection pixels. In some embodiments, the system is capable of a first mode of operation, the first mode configured to shift the pixelated output into the plurality of projection pixels having high-contrast and pixel lines between adjacent projection pixels. In certain embodiments, the system has a second mode of operation, the second mode configured to shift the respective pixelated output into the plurality of projection pixels, and further configured to, at least partially, homogenize the electromagnetic radiation pattern of a projection relative to the first mode of operation.

[0015] In certain embodiments, a computer implemented method for 3D printing is described, the method comprising: controlling, by at least one processor, a source of electromagnetic radiation; transforming, by a pixel generator, the electromagnetic radiation into a pixelated output from respective source emissions; shifting, by a pixel shifter, respective pixelated outputs into a plurality of projection pixels; and triggering, by the at least one processor, a second mode of operation, the second mode configured to shift the respective pixelated output into the plurality of projection pixels, the triggering including an act of homogenizing, at least partially, an electromagnetic radiation pattern of a projection relative to a first mode of operation, wherein the first mode of operation is configured to shift the pixelated output into the plurality of projection pixels having high-contrast and pixel lines between adjacent projection pixels.

[0016] #14469326vl According to some embodiments, an article made by 3D printing is described. In certain embodiments, the article comprises at least two non-parallel lines within the article, wherein a change in refractive index, density, and / or modulus along a distance of at least 1 mm of each of the at least two non-parallel lines differs from a change in refractive index, density, and / or modulus along at least 1 mm of the other line by at least 5%.

[0017] In certain embodiments, an article made by 3D printing comprises no line within the article which, along a distance of at least 1 mm, is there a change in refractive index, density, and / or modulus of more than 1%.

[0018] Other advantages and novel features of the present disclosure will become apparent from the following detailed description of various non-limiting embodiments of the disclosure when considered in conjunction with the accompanying figures. In cases where the present specification and a document incorporated by reference include conflicting and / or inconsistent disclosure, the present specification shall control.

[0019] BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Non-limiting embodiments of the present disclosure will be described by way of example with reference to the accompanying figures, which are schematic and are not intended to be drawn to scale unless otherwise indicated. In the figures, each identical or nearly identical component illustrated is typically represented by a single numeral. For purposes of clarity, not every component is labeled in every figure, nor is every component of each embodiment of the disclosure shown where illustration is not necessary to allow those of ordinary skill in the art to understand the disclosure. In the figures:

[0021] FIG. 1A shows, in accordance with certain embodiments, a schematic diagram of a system comprising a homogenizer configured to at least partially homogenize an electromagnetic radiation pattern.

[0022] FIG. IB shows, in accordance with certain embodiments, schematic diagrams of different types of electromagnetic radiation pattern homogenization.

[0023] FIG. 1C shows, in accordance with certain embodiments, a schematic diagram of a homogenizer rotatable relative to an optical axis of electromagnetic radiation pattern incident to the homogenizer.

[0024] FIG. ID shows, in accordance with certain embodiments, a schematic diagram of a homogenizer tiltable relative to an optical axis of an electromagnetic radiation pattern incident to the homogenizer.

[0025] #14469326vl FIG. IE shows, in accordance with certain embodiments, a schematic diagram of a homogenizer rotatable relative to an optical axis of an electromagnetic radiation pattern incident to the homogenizer and tiltable relative to the optical axis of the electromagnetic radiation pattern incident to the homogenizer.

[0026] FIG. 2A shows, in accordance with certain embodiments, a schematic diagram of a system comprising a homogenizer that is at least partially reflective of electromagnetic radiation.

[0027] FIG. 2B shows, in accordance with certain embodiments, a schematic diagram of a homogenizer that is at least partially reflective of electromagnetic radiation and rotatable relative to an optical axis of electromagnetic radiation pattern incident to the homogenizer.

[0028] FIG. 2C shows, in accordance with certain embodiments, a schematic diagram of homogenizer that is at least partially reflective of electromagnetic radiation and tiltable relative to an optical axis of an electromagnetic radiation pattern incident to the homogenizer.

[0029] FIG. 2D shows, in accordance with certain embodiments, a schematic diagram of homogenizer that is at least partially reflective of electromagnetic radiation, rotatable relative to an optical axis of an electromagnetic radiation pattern incident to the homogenizer, and tiltable relative to the optical axis of the electromagnetic radiation pattern incident to the homogenizer.

[0030] FIG. 3 shows, in accordance with certain embodiments, a schematic diagram of a system comprising a homogenizer configured to at least partially diffuse an electromagnetic radiation pattern.

[0031] FIG. 4 shows, in accordance with certain embodiments, a schematic diagram of a system comprising a homogenizer positioned in association with a support.

[0032] FIG. 5A shows, in accordance with certain embodiments, a schematic diagram of a system comprising a homogenizer and additional components.

[0033] FIG. 5B shows, in accordance with certain embodiments, a schematic diagram of a system comprising at least two homogenizers.

[0034] FIG 6 is, in accordance with certain embodiments, a block diagram of an example system including a controller.

[0035] FIG. 7 is, in accordance with certain embodiments, a block diagram of an example system, emission source, pixel generator, and pixel shifter, according to one embodiment; and

[0036] FIG. 8 is, in accordance with certain embodiments, a block diagram of an example special-purpose computer system improved by the functions and / or processes disclosed herein;

[0037] FIG. 9 illustrates, in accordance with certain embodiments, a projection of a pixel array comprising multiple pixel lines.

[0038] #14469326vl FIG. 10 illustrates, in accordance with certain embodiments, an example embodiment of projector attachment apparatus.

[0039] FIG. 11 illustrates, in accordance with certain embodiments, a cross-sectional view of the projector attachment apparatus.

[0040] FIG. 12 illustrates, in accordance with certain embodiments, a ray of light bending as a result of passing through a tilted glass.

[0041] FIG. 13A illustrates, in accordance with certain embodiments, rays from a pixel without a self-induced waveguide effect.

[0042] FIG. 13B illustrates, in accordance with certain embodiments, rays from a pixel undergoing a self-induced waveguide effect.

[0043] FIG. 13C illustrates, in accordance with certain embodiments, how translating the projection overcomes the self-induced waveguide effect.

[0044] FIG. 13D illustrates, in accordance with certain embodiments, an angled pull selfinduced waveguide effect.

[0045] FIG. 14A illustrates, in accordance with certain embodiments, a projection of an array of pixels.

[0046] FIG. 14B illustrates, in accordance with certain embodiments, a projection of an array of pixels making use of an XPR device.

[0047] FIG. 14C illustrates, in accordance with certain embodiments, a projection of an array of pixels making use of the apparatus from FIG. 10 where the radius of translation was approximately 43 microns.

[0048] FIG. 14D illustrates, in accordance with certain embodiments, a projection of an array of pixels making use of the apparatus from FIG. 10 where the radius of translation was approximately 75 microns.

[0049] FIG. 14E illustrates, in accordance with certain embodiments, a projection of an array of pixels making use of the apparatus from FIG. 10 where the radius of translation was approximately 100 microns.

[0050] FIG. 15 illustrates, in accordance with certain embodiments, an example embodiment of the present disclosure for varying the pattern of translating light.

[0051] FIG. 16 illustrates, in accordance with certain embodiments, an example embodiment of an angled Z-arm.

[0052] #14469326vl DETAILED DESCRIPTION

[0053] The present disclosure involves altering electromagnetic radiation (ER) directed toward a substance and / or object in a way that affects the radiation and its impact on the substance and / or object. In one set of embodiments of this disclosure, electromagnetic radiation is provided in a pattern, and the pattern is altered in a way that makes it less precise; it is homogenized at least to some extent. This is counterintuitive to, and taught away from, by conventional systems and methods where precision in electromagnetic radiation is a goal.

[0054] One example of the contribution of this disclosure involves equipment, methods, and / or control (e.g., computer-guided control) of systems to alter patterns of electromagnetic radiation rendering them less precise. Any of a variety of electromagnetic radiation patterns can be altered in accordance with this disclosure. Those of ordinary skill in the art will recognize the breadth of its coverage and impact, and while most examples provided in this disclosure relate to photochemically-initiated reactions, i.e., chemical reactions caused by light, the disclosure and its impact are not limited to this. Example reactions involved include photoinitiated printing, photolithography, 3D printing (e.g., digital light processing), etc., although this list is not exclusive of the coverage of this disclosure and the ways in which this disclosure can be put to use.

[0055] Further and more specific examples described in this disclosure will relate to photoinitiated three-dimensional (3D) printing, but it is to be understood that all such examples are provided for simplicity only and can be applied to other activities described above and / or elsewhere herein, and / or where their application would be understood by those of ordinary skill in the art to be useful.

[0056] As noted, one aspect of the invention involves rendering electromagnetic radiation, for example electromagnetic radiation patterns, less precise. Electromagnetic radiation patterns encompass a broad scope including, for example, patterns for photolithography for the formation of circuitry and other objects, selective curing of a resin or other photoinitiated polymeric reaction, 3D printing, or the like. In most of these instances, in known, state-of-the-art systems and methods, precision is sought after. For example, in photolithography and / or 3D printing, a pattern of electromagnetic radiation is imparted upon a precursor of a circuit, 3D object, or the like, where very precise delineation and definition of boundaries and contours of the object are desired. In many arrangements, these electromagnetic radiation patterns are digital, i.e., include pixels (although analog and / or non-digital electromagnetic radiation patterns also can be used, and can be affected by the teachings of this disclosure). In one example involving conventional photoinitiated 3D printing with a digital, or pixelated electromagnetic radiation pattern, it is

[0057] #14469326vl desired to maximize precision in the form of differentiation of pixels from each other without interference, blurring, scattering, or the like so that, as noted, precision in shape or form of a final object can be obtained.

[0058] In the present disclosure, the inventors have recognized that a different approach can be beneficial; an approach where precision is reduced in electromagnetic radiation patterns that are directed toward substances such as precursors of objects, for example in 3D printing processes. Turning to one example, a digital or pixelated pattern directed toward precursors of 3D printing objects, this disclosure involves at least partially homogenizing such patterns. This means reducing, to at least some extent, precise delineation and differentiation between pixels in the pattern. This can find many uses that will be understood by those of ordinary skill in the art with the benefit of this disclosure, one example of which is the 3D printing of devices designed to interact with light (or other electromagnetic radiation) when put to use, for example lenses, and / or other optical devices which, in use, can focus, shape, diffuse, re-direct, or otherwise interact with light (wherever “light” is used herein, this means light that is visible and / or non- visible including, e.g., IR and UV light). In the example of a 3D printed lens, it can be desirable for the lens to interact differently with light at different places on the lens, which for example, vary in thickness, curvature, and / or refractive index. Where the presence of pixels, and interactions or boundaries between pixels, in an electromagnetic radiation pattern imparted upon a precursor to form a 3D printed lens result in features in the lens that involve lines, other types of relatively abrupt changes, and / or other non-homogeneity, rather than a less-perceptible, smoother transition across the lens (or other object), this can involve compromised performance of the final, 3D printed optical device or other object.

[0059] The present disclosure addresses this by at least partially homogenizing an electromagnetic radiation pattern, such as a digital; pixelated pattern, to reduce such features in the final product. Homogenizing the pattern involves reducing the digital / pixelated precision at least partially and can be accomplished in a number of ways, some of which are described herein. One technique involves adding a homogenizer to a system including an apparatus for carrying out a photochemical reaction, such as 3D printing apparatus. Another technique involves homogenizing electromagnetic radiation by controlling and / or altering an existing component of such apparatus. These techniques are described more fully below and enable various aspects of this disclosure including methods for 3D printing or carrying out other photoinitiated reactions, systems, and apparatuses related to these reactions, and final products resulting from these reactions. Where any description is provided in connection with one of these aspects, it is to be understood that the teaching can be applied to other aspects. Those of

[0060] #14469326vl ordinary skill in the art, with the benefit of this disclosure, will be able to use other techniques to meet the result covered by this disclosure.

[0061] As noted, one aspect involves systems including an added or auxiliary homogenizer. Such a homogenizer can be an optical device that homogenizes electromagnetic radiation by moving during photoinitiated radiation and / or can be a device that does not move (although it can), which includes homogenizing qualities, such as particles, imperfections, or other features or additives that diffuse and / or scatter light, or the like. As noted, each of these can be used separately or together. The homogenizer can itself be an additive added to existing apparatus, such as particulate matter added to a substance (such as a solid or fluid) present in a known system. Any or all of these techniques can be used in combination. For example, a system can include an auxiliary homogenizer, or a system can be altered so as to more greatly homogenize light, or a combination. Homogenizers, and techniques for homogenizing light with or without an added homogenizer, are described below.

[0062] Projector systems typically used in 3D printing are designed primarily to create high contrast between pixels. The darkened areas around the pixel are called “pixel lines.” For curing resin, the pixel lines can degrade the performance of the resin. The UV energy will solidify the center of the pixel while leaving the edges under cured. The objective of the present disclosure, in some embodiments, is to remove the pixel lines by spreading the electromagnetic radiation (e.g., UV light) across the resin.

[0063] 3D printing takes advantage of electromagnetic radiation (ER) projector systems to trigger polymerization over a large area at once. One typical projector system used in DLP 3D printing makes use of a spatial light modulator such as a digital micromirror device (DMD). DMD’s make use of an array of thousands of micromirror devices that each individually rotate between degrees of “on” and “off’. ER from a source within the projector reflects off the DMD in the “on” position and into the 3D printing apparatus to trigger polymerization. When ER strikes a micromirror device in the “off’ position, it is not reflected and does not trigger polymerization within the area of the device’s projection area. Each DMD in the “on” position represents a pixel of light, and the DMD allows for highly precise control of the pattern of ER emitting from the projector by triggering polymerization only within the area of reflection of micromirror devices in the “on” position.

[0064] Within a DMD array, there are gaps between each individual micromirror. When projectors emit ER that is designed to be perceived by the human eye, these gaps provide a contrast that increases the eye’s ability to perceive the projected image. When these DMDs are used in projectors for 3D printing, these gaps can cause inconsistent curing. Inconsistent curing

[0065] #14469326vl also results from a Gaussian distribution of energy from the pixel where the intensity of light is greater in the center of the pixel than at the edges. More evenly distributing ER that emits from a projector employing a DMD array would remove the inconsistencies in curing caused by the gaps.

[0066] The present disclosure overcomes issues of polymerization within 3D printing (e.g., DLP 3D printing), for example, caused by pixel gaps between micromirrors within a DMD as well as issues in uniformity of the distribution of light coming off each mirror in a DMD. The system also applies to other pixel based ER sources such as LCD based light engines. To overcome these inconsistencies, embodiments of the present disclosure homogenize electromagnetic radiation patterns by translating the position of projections from a pixel to evenly distribute the emission from the center region of the pixel across a larger area than the center region of the original area of the pixel. In an embodiment, distributing the emission from the center region of a pixel across the entire area of a pixel and its surrounding gaps more evenly distributes ER over that area. This also effectively decreases the ER intensity directly in the center region of the pixel by translating the center position of the pixel over a larger area. As such, the present disclosure also overcomes inconsistent curing that can result from Gaussian distribution of energy across the pixel.

[0067] In an embodiment, the devices, systems, and / or methods described herein translate pixel positions using a homogenizer such as a spinning transparent article positioned between the projector and the projection target that alters the path of the rays of ER reflecting off of the spatial light modulator (e.g., DMD) to achieve a more homogenous distribution of ER. In an embodiment, the spinning transparent article is a flat sheet of glass. In an embodiment, a transparent article is sandblasted glass. In an embodiment, multiple transparent articles are used. In an embodiment, the devices and / or systems described herein further comprise a diffusing mask. In an embodiment, the diffusing mask is integrally formed with the transparent article. In an embodiment, the diffusing mask is separate from the transparent article. In an embodiment, the device and / or systems described herein further comprise a de-speckler positioned between the transparent article and the precursor of a photochemical reaction (e.g., a polymerizable liquid). In an embodiment, the devices and / or systems described herein comprise a polarized film positioned between the transparent article and the polymerizable liquid. In an embodiment, the device and / or systems described herein comprise a combination of transparent articles, diffusers, de-specklers, or polarizing films positioned between the ER source and the polymerizable liquid. In an embodiment, the transparent article is a lens. In an embodiment, the lens further comprises a concave curve, a convex curve, plano-convex, plan-concave, or a

[0068] #14469326vl combination thereof. In an embodiment, the spinning glass is positioned within the projector before the light enters the lens of the projector. In an embodiment, the spinning glass is positioned in between the elements that make up the lens of the projector. In an embodiment, the spinning glass is separate from the projector. In an embodiment, the spinning glass is integrally formed within the lens array of the projector. In an embodiment, the glass is tilted with respect to the orthogonality of the projector. In an embodiment, the angle of the glass with respect to the projector changes in a cyclical pattern. In an embodiment, the cyclical pattern is an epitrochoid. In an embodiment, the angle of the glass with respect to the projector changes in a non-cyclical pattern. In an embodiment, the pattern of change of the angle is altered throughout an example additive manufacturing process. In an embodiment, as the projector light travels through the glass, the angle of incident, the refraction index of the glass, and the thickness of the glass bend the light effectively translating the pixel position. In an embodiment, the angle of the glass relative to the projector changes while the glass is spinning. In an embodiment, Snell’s law is used to calculate the positional translation of a given pixel caused by the spinning and / or tilting of the glass.

[0069] In an embodiment, angular movement of the homogenizer (e.g., the angle change and / or spinning) occurs independently of the projection and ER emission from the projector. In an embodiment, the spinning and / or angle change of the devices, systems, and / or methods described herein occurs independently of any spinning and / or angle change of the projector or projector lens system. When the glass is desynchronized from the DMD array and spins and / or rotates independently of the movements of the micromirrors, the overall randomness of the distribution of the ER is improved. In an embodiment, the movement of the glass is completely random. In an embodiment, the greater the overall randomness of the positional translation of the ER from the pixel, the more effective the distribution of the ER across the entire area. The more effective the distribution of ER intensity is, the less likely there will be defects and inconsistencies within the solidified product caused by the pixel lines. In an embodiment, effectively distributing ER intensity overcomes “hot spots”, or areas that, despite the changing angle of the glass relative to the projector, certain projection areas of polymerizable liquid receive a greater distribution of ER than others. These “hot spots” can cause a greater degree of solidification during the additive manufacturing process, which can cause strain within the polymer network of the cured part or other physical deformations. In an embodiment, the speed of the rotation determines how often an area of the resin receives an ER dosage. In an embodiment, the angle of the glass determines the radius of the pattern. In an embodiment, the rotational axis of the glass can be centered with the projector center or can be offset. If the

[0070] #14469326vl projector center is in line with the rotational axis of the glass, the center pixels do not translate as far, which can result in a “hot spot”. Conversely, if the rotational axis of the glass is offset from the projector center, all the pixels may be translated more equally.

[0071] Removing the inconsistent intensities is particularly valuable when additively manufacturing a product where there is a large difference between the index of refraction of the solidified article and the liquid resin. Based on Snell’s law, a large change in the index of refraction between the liquid resin and the solidified part will cause the ER to refract. This can result in vertical imperfections as the ER is refracted directionally as it enters the product. The Critical Angle of internal reflection of the light within the product is proportional to the sin'1of the ratio of the index of the product to the index of the polymerizable material. When the projection remains stationary, light will constantly reflect inward at this critical angle in the center of the pixel when it passes from the resin into the solidified product, which will result in imperfections in the final product (i.e., visual aberrations). Translation of a given pixel over an area to distribute the intensity of the ER can overcome these defects because the light is not constantly being refracted at the same location and angle. In an embodiment, a diffusing mask is placed over the glass to more effectively distribute the light over an area. In an embodiment, the diffusing mask varies in pattern and distribution throughout. In an embodiment, a diffusing mask is used in combination with rotational and / or tilting the glass.

[0072] Optical lenses are an example product where there is a large change in index of refraction between the polymerizable material and the solidified product. Using typical DLP projectors to produce optical lenses can lead to visual aberrations forming within the optical lens. These visual aberrations are the result of the ER from the projector being constantly refracted at the same direction and angle as it passes from the resin into the solidified lens. Consistent refraction causes light to concentrate in certain regions of the lens and fail to reach other regions of the lens. As such, every component of the lens does not achieve the same degree of solidification on the printer. This can cause structural defects in any part. For optical lenses, consistent refraction at the same direction and angle over an entire printing process also results in visual aberrations that are perceptible by the eye. These aberrations prevent the lens from functioning properly. To prevent these aberrations, the present disclosure provides a method for 3D printing lenses that more evenly distributes the rays of ER emitting from the projector. This even distribution of energy prevents the visual aberrations caused by pixel lines. Spinning the glass causes the distribution of ER to be more even across the lens as it forms. This more even distribution will result in more evenly distributed refraction as the ER enters the lens. This limits the creation of visible aberrations because the refraction is not consistently the same direction and angle, which

[0073] #14469326vl is the case if the projection were not translated. Tilting the glass while it is spinning more effectively distributes the energy across the entire area of the lens. It also changes the angle at which the rays of ER interact with the interface between the polymerizable material and the lens. In an embodiment, tilting the glass in combination with spinning the glass and varying the rates of spin / tilt throughout creates a random distribution of ER. This random distribution of ER prevents the formation of the visual aberrations that result in consistent, non-random distribution of energy because it prevents the refraction of the ER as it enters the product from occurring at the same angle and direction throughout the process.

[0074] In an embodiment, the present disclosure provides an apparatus and method for additively manufacturing optical lenses from a polymerizable material. In an embodiment, a method for manufacturing optical lenses further comprises using DLP additive manufacturing. In an embodiment, a method for manufacturing optical lenses comprises using a projector system comprising one or more DMD arrays wherein the projection from the DMD array is translated over an area such that the energy reflecting off the DMD is more evenly distributed over the area. In an embodiment, this translation occurs because of a spinning transparent article positioned between the DMD array and the polymerizable material. In an embodiment, this translation occurs because of a tilted transparent article positioned between the DMD array and the polymerizable material. In an embodiment, the transparent article further comprises a diffusing mask. In an embodiment, the spinning and / or tilting is independent of the movement of the DMD array. In an embodiment, multiple transparent articles are positioned between the DMD array and the polymerizable material.

[0075] In an embodiment, a combination of rotation, spinning, and diffusion are used. In an embodiment, multiple transparent articles are positioned between the projector and the projection target. In an embodiment, each transparent article rotates, spins, or diffuses independently of other transparent articles. In an embodiment, a transparent article is translated circularly in addition to rotating and tilting. Controlled combinations of glass movement are ideal for the present disclosure because combinations of movement increase the randomness of the pixel translation. Perfect randomness is difficult to achieve mechanically as the repeated motion will likely have some form of pattern associated with it, therefore combinations of nonsynchronized movement of the glass(es) can increase the overall randomness of the distribution compared to single movements. In an embodiment, a vibrational motor or some other nonmechanical means of movement associated with the projector or glass would increase the overall randomness of the distribution.

[0076] #14469326vl In an embodiment, the spinning, tilting, translation, vibration, diffusion, or combination thereof of the projection by the glass occurs in a random manner. In an embodiment, the spinning, tilting, translation, vibration, diffusion, or combination thereof of the projection by the glass occurs in a patterned manner. Patterns are much simpler to achieve mechanically, but true randomness is desired for present disclosure to ensure the most random distribution of energy from the projectors. In an embodiment, one cycle of the patterned manner occurs faster than the latent reaction time of the polymerization reaction. The latent reaction time is the time accumulated between stopping the ER and the reaction stopping. The latent reaction time becomes critical when a micromirror switches from “on” to “off’. In an embodiment, a 3D printing process making use of the present disclosure is a continuous 3D printing process. Continuous 3D printing processes are preferable for producing optical lenses as layer-by-layer techniques produce layer lines that are perceptible by the eye and interfere with the functionality of the lens. Ensuring that the pattern of translation takes less time than the latent reaction time ensures a consistent index of refraction in the Z-direction, which allows for a continuous printing process.

[0077] With materials that have a high index of refraction delta between the resin and the cured state, a self-induced waveguide can form from the center rays that turn the angle of the noncenter rays (marginals) from the light coming from an individual DMD mirror inwards. An illustration of this self-induced waveguide effect is illustrated in FIG. 13B. When the waveguides eventually fill in the gap between rays, the regions of the product to which light was not directed by the waveguide are cured differently than the regions cured by the center rays. This difference of cure can result in a difference in the index of refraction between regions cured by center and marginal rays. These differences can be measured in a number of ways such as looking at the modulus differences with AFM, looking at the index differences with confocal Raman spectroscopy, visualizing pixel lines under polarizing microscope, looking at directional index differences with an inframeter, or through x-ray scattering and diffraction techniques. The diffraction pattern could also be seen through shining a laser with the printed part. In an embodiment of an optical lens, the index difference from the highest to lowest across the lens is less than 50%, more preferably less than 40%, more preferably less than 30%, more preferably less than 20%, more preferably less than 10%, more preferably less than 5%, more preferably less than 4%, more preferably less than 3%, more preferably less than 2%, more preferably less than 1%. In an embodiment of an optical lens, the highest index of refraction within the lens is within 0.5 of the lowest index of refraction within the lens, more preferably within 0.4, more preferably within 0.3, more preferably within 0.2, more preferably within 0.1, more preferably

[0078] #14469326vl within 0.05, more preferably within 0.03, more preferably within 0.01. In an embodiment of an optical lens, the AFM modulus difference between the highest modulus and the lowest modulus of the lens is less than 50%, more preferably less than 40%, more preferably less than 30%, more preferably less than 20%, more preferably less than 10%, more preferably less than 5%, more preferably less than 4%, more preferably less than 3%, more preferably less than 2%, more preferably less than 1%. In an embodiment, an optical lens is a gradient index of refraction (GRIN) lens where the index of refraction varies throughout. In an embodiment, a GRIN lens is produced purposefully such that different regions of the lens possess a different index of refraction. In an embodiment, purposefully changing the index of refraction at a specific location within the lens can correct for high level visual aberrations.

[0079] TI (Texas Instruments) offers a technology called XPR (expanded Pixel Resolution) that works on the principle of pivoting a glass sheet on one or two axes to shift the light path a fraction of a pixel. This device is between the DMD and the projection lens. It was designed and engineered to perfectly sync with the DMD mirrors so that the mirrors are off during any movement of the XPR and on when the XPR is in one of its projection positions. It does this because if the mirrors were in the on state during the movement, the final perceived pixel when watching a movie with a projector would have a lower resolution. This crispness is desirable for all imaging and viewing uses of projectors and even for many 3D printing applications. For printing lenses, this is the opposite of what is needed. This is because lenses needs internal homogeneity within the lens over crisp sharp edges. For opaque parts, this level of homogeneity is not necessary, and there is a definite tradeoff in precision on the edges of the part. As such, standard 3D printing applications would not sacrifice this amount of resolution to achieve this level of homogeneity. An embodiment of the present disclosure makes use of an XPR or XPR like device that is decoupled from the DMD synchronization. In an embodiment, the XPR devices does not pause at each pivot position in a consistent pattern. In other embodiments, the XPR changes the pitch and pattern to induce randomness during a print. In other embodiments, the XPR is paired with any of the other embodiments described herein.

[0080] In an embodiment, the glass does not physically rotate, but rather the angle of the glass rotates to cause the same shift of the light path. A suitable apparatus may include an actuator that translates the edges of the glass up and down relative to the projector throughout the printing process. In an embodiment, translators are used at multiple equidistant points on the glass. In an embodiment, each of the translators moves their respective region of the glass randomly, causing the tilt relative to the projector to change randomly. In an embodiment, the spinning glass ring is also translating linearly (e.g., in X & Y) to further blend any rotational

[0081] #14469326vl patterns that form from the spinning glass itself. In another embodiment, vibration is used to add randomness into the pattern formed by the light.

[0082] Helix Angle

[0083] In an embodiment, the glass is held in place by a cylinder. In an embodiment, the cylinder is holding the glass using a helix angle. In an embodiment, the helix angle allows for control over both the tilt and the rotation of the glass. In an embodiment, the cylinder is cut in half. In an embodiment, the top half of the cylinder (holding the glass) is affixed to the bottom half. In an embodiment, the top half of the cylinder is removably coupled to the bottom half. In an embodiment, a rotational actuator spins the cylinder. In an embodiment, the top half of the cylinder is rotated relative to the bottom half of the cylinder. In an embodiment, the top half of the rotation of the cylinder causes the glass to tilt as a result of the helix angle. The rotation of the top half changes the incident angle of the projector to the glass thereby changing the angle of pixel displacement. This feature allows the experimenter to “dial-in” the displacement. In an embodiment, the angle of the glass relative to the projector is controlled by multiple motors. In an example embodiment, the angle of the glass relative to the projector is controlled by four motors. In an embodiment, the motors are affixed to actuators that translate the position of an aspect of the cylinder up and down throughout the additive manufacturing process. The use of multiple motors controlling different positions of the spinning lens allows for the greatest degree of control of the angle of the glass relative to the ER source throughout the additive manufacturing process. It also allows for the creation of more complex patterns of pixel translation when compared to an apparatus making use of fewer motors. In an embodiment, the pattern of angle may be altered throughout the additive manufacturing process. In an embodiment, the motors are under control of a controller that dictates the speed and amount of translation that each motor dictates. In an embodiment, the central controller performs independent calculations to determine the angles of the glass at any point during the additive manufacturing process.

[0084] Speed Variation

[0085] In an embodiment, when the speed of the rotation of glass is held constant, a coordinate on the glass will align with the same coordinate within the polymerizable liquid. Changing the speed of the rotation will change where the glass aligns with the resin. Using a regime for varying speed, the glass will vary its location relative to the resin. In an embodiment, an RPM sensor provides feedback to assist in modeling the physics of the optics and help in tuning optimal performance. In an embodiment, one or more motors control the speed of rotation of the

[0086] #14469326vl glass. In an embodiment, the one or more motors are under control of a common controller. In an embodiment, the RPM sensor provides feedback to the common controller.

[0087] Angled Pull

[0088] In an embodiment, the present disclosure provides a further means of distributing ER over the polymer network of an additively manufactured part by angling the direction of polymerization relative to the ER projector. DLP additive manufacturing apparatuses typically make use of a Z-arm onto which the additively manufactured part solidifies from the polymerizable liquid supply. The Z-arm moves the part away from the ER source and allows additional polymerizable liquid to replace the freshly cured polymerizable liquid to be solidified. Angling the direction of pull of the Z-arm relative to the ER source can further overcome “hot spot” problems associated with embodiments of the present disclosure by further distributing the ER over the polymer network of the additively manufactured part. In an embodiment, the present disclosure provides a means of distributing ER over the polymer network of an additively manufactured party by combining an apparatus for distributing ER from a DMD device with an angled direction of pull by a Z-arm. In an embodiment, this angle is 1 degree, 2 degrees, 3 degrees, 4 degrees, or 5 degrees. In an embodiment, the angle of the Z-arm relative to the ER source is greater than the greatest angle of offset of the spinning glass. If the angle of the Z-arm relative to the ER sources is smaller than the greatest angle of offset of the spinning glass, then the hot spot will translate within the area of print but will not be fully eliminated. In an embodiment, the ER source projects ER vertically and the Z-arm pulls at an angle relative to the vertical ER source. In an embodiment, the Z-arm pulls vertically, and the ER source is angled relative to the vertical pull of the Z-arm. In an embodiment, the angle of the Z-arm relative to the projector should be as small as possible in order to ensure that the rays of ER remain as vertical as possible so long as the angle is greater than the greatest angle of offset of the spinning glass. If an associated additive manufacturing apparatus makes use of a liquid interface, then angling the direction of pull of the Z-arm relative to the ER source is more practical than angling the projector source relative to the Z-arm. In an embodiment, offsetting the rays of ER from the angle of pull in combination with a cyclical pattern of diffusing ER using a spinning glass overcomes “hot spot” issues that may arise from the difficulty in achieving true randomness with the cyclical pattern of angling the spinning glass relative to the ER source.

[0089] When additively manufacturing a product using an angled Z-arm, there must be changes made to source images used by the projectors to form the layers of the additively manufactured part. In an embodiment, Computer Assisted Designs (CAD’s) of the product to be formed are sliced into successive images (an image stack) where each image corresponds to a layer of the

[0090] #14469326vl part to be formed. In an embodiment, angling the Z-arm requires the slicing of the image stack to include some form of “shearing”. In an embodiment, shearing the CAD involves slicing the image such that the center of the image mirrors the angle of the Z-arm. In an embodiment, shearing the CAD involves free-forming the images such that the images of the image stack takes the angle of the Z-arm into account.

[0091] For additively manufacturing using a polymerizable liquid with a high index of refraction, the angle of the Z-arm relative to the ER source increases as the index of refraction of the material increases. This counteracts a correspondingly stronger self-induced waveguide effect that occurs with higher index materials. In an embodiment, the angle of the Z-arm relative to the ER source is as small as possible when considering the angle of the spinning glass and the index of refraction of the material to mitigate issues with over / under curing of different regions of the part. In an embodiment, a DMD apparatus has a directional pixel grid wherein the micromirrors are angled on a given axis when changing between “on” and “off’ positions. When a group of micromirrors is in the “on” position, they are angled in the same direction. In an embodiment of the present disclosure comprising an angled Z-arm, the direction of tilt of the Z-arm is angled against the direction of tilt of the micromirrors when they are in the “on” position such that the angle is not parallel nor perpendicular to the direction of the edges of the micromirrors. In an embodiment, this more effectively blends the ER reflects off the micromirrors and into the curing part.

[0092] In an embodiment, the present disclosure further comprises a means of eliminating the spread of the ER reflecting off the DMD array. In an embodiment, the present disclosure provides a combination of angling the direction of pull by the Z-arm relative to the ER source and eliminating the angle of the ER reflecting off the DMD array. Typical ER sources used for additive manufacturing have a degree of spread in their projections. This spread causes the ER from the source to enter the polymerizable liquid at different angles, which can cause difficulties for part geometry and homogeneity within the polymer network across the part. In an embodiment, the devices and / or systems described herein further comprise a collimating lens positioned between the ER source and a transparent article. A collimating lens forces the rays of ER reflecting off the DMD array to become parallel with one another as it passes through the lens. This collimating effect flattens the image from the ER source and ensures that the rays stay essentially vertical as they pass through the transparent article. In an embodiment, eliminating the spread from the ER source facilitates each ray from the ER source to contact the polymerizable liquid at the same depth, which means that each ray will transfer the same degree of energy into the part’s polymer network as it forms. In an embodiment, spread from the ER

[0093] #14469326vl source is eliminated using a telecentric lens wherein the lens creates a constant magnification in addition to causing the rays to become parallel to become parallel with the optical axis of the lens. In an embodiment, a telecentric lens is an object-space telecentric lens that eliminates spread by creating telecentricity at the object. In an embodiment, an object-space telecentric lens is positioned closest to the ER source and furthest from the polymerizable liquid. In an embodiment, a telecentric lens is an image-space telecentric lens that eliminates spread by creating telecentricity at the image. In an embodiment, an image-space telecentric lens is positioned furthest from the ER source and closest to the polymerizable liquid supply. In an embodiment, the devices, systems, and / or methods described herein utilize a combination of object-space and image-space telecentric lenses. In an embodiment making use of multiple lenses, the lenses may be offset to one another in the Z-direction. In an embodiment making use of multiple lenses, the lenses may overlap with one another in the X or Y directions.

[0094] Turning now to the figures, specific non-limiting embodiments are described in more detail. It should be understood that various features of the separately described embodiments may be used together as the current disclosure is not limited to the specific embodiments depicted in the figures and described below.

[0095] According to certain embodiments, a system described herein comprises a source of electromagnetic radiation. For example, FIG. 1A shows, in accordance with certain embodiments, a schematic diagram of a system 102a comprising source 104 of electromagnetic radiation. As used herein, the term electromagnetic radiation refers to energy propagated through space or a medium in the form of oscillating electric and magnetic fields, and which can include radiation across any portion of the electromagnetic spectrum, such as ultraviolet (UV), visible, infrared (IR), microwave, and / or radio-frequency radiation. In certain embodiments, the electromagnetic radiation comprises UV electromagnetic radiation (e.g., having a wavelength from 10 nm to below 400 nm). In some embodiments, the electromagnetic radiation comprises visible electromagnetic radiation (e.g., having a wavelength from 400 nm to below 700 nm). In some embodiments, the electromagnetic radiation comprises infrared (IR) electromagnetic radiation (e.g., having a wavelength from 700 nm to 1 mm).

[0096] In certain embodiments, the electromagnetic radiation comprises an electromagnetic radiation pattern. Referring, for example, to FIG. 1A, the electromagnetic radiation emitted from source 104 comprises electromagnetic radiation pattern 114 (e.g., electromagnetic radiation pattern 114a and 114b). According to some embodiments, the pattern comprises electromagnetic radiation (e.g., UV, visible, and / or IR radiation) that has any defined spatial and / or temporal distribution of electromagnetic radiation, whether uniform or non-uniform. As would generally

[0097] #14469326vl be understood by a person of ordinary skill in the art, the pattern is not limited to visible patterns perceptible to the human eye, but encompasses any structured distribution of electromagnetic radiation that can be detected by a photosensitive material, optical sensor, or other detection mechanism.

[0098] The source of the electromagnetic radiation may comprise any of a variety of suitable sources. In some embodiments, for example, the source of the electromagnetic radiation comprises a lamp and / or bulb (e.g., mercury and / or xenon lamps and / or bulbs), a laser (e.g., a UV laser, an IR laser), a light emitting diode (LED), a semiconductor, and the like. Other sources of electromagnetic radiation are also possible.

[0099] According to some embodiments, the system comprises a support. Referring, for example, to FIG. 1A, system 102a comprises support 108. In certain embodiments, the support is a projection target, i.e., the object onto which electromagnetic radiation is projected.

[0100] The support may, in some embodiments, be configured to support a precursor of a photochemical reaction. For example, referring to FIG. 1A, support 108 is configured to support precursor 110 of a photochemical reaction.

[0101] A support (e.g., configured to support a precursor of an electrochemical reaction) is a component which those of ordinary skill in the art will clearly understand to have structural significance, differentiating it from, for example, any random support for supporting any object for any purpose whatsoever. Those of ordinary skill will understand that such a support can include, for example, a stage for photolithography, a vessel, container, and / or tank into which a precursor of a photochemical reaction (e.g., a 3D printing reaction) can be placed, and the like. Those of ordinary skill can inspect such supports and differentiate them from supports that are not structurally configured for this purpose. In some cases, those of ordinary skill will observe overall systems configured for carrying out a photochemical reaction, such as photoinitiated 3D printing, will fully understand the meaning of this terminology relating to those systems, and will understand which component of the system is a support for supporting a precursor of an photochemical reaction.

[0102] As described above, the support (e.g., support 108) may be configured to support a precursor of a photochemical reaction (e.g., precursor 110). According to some embodiments, the support contains the precursor of the photochemical reaction. For example, as shown in FIG. 1A, support 108 contains precursor 110 of the photochemical reaction.

[0103] The precursor of the photochemical reaction may be or comprise any of a variety of suitable materials. In some embodiments, for example, the precursor of the photochemical reaction is a photopolymerizable resin (e.g., a polymerizable liquid). In some such

[0104] #14469326vl embodiments, the support is configured to support the photopolymerizable resin. In certain embodiments, the support contains the photopolymerizable resin. According to some embodiments, the precursor of the photochemical reaction is a 3D printing precursor. In some such embodiments, the support is configured to support the 3D printing precursor. In certain embodiments, the support contains the 3D printing precursor. Other materials for the precursor are also possible.

[0105] In certain embodiments, the support (e.g., support 108) is configured to support a solidifiable material (e.g., a material that is capable of being solidified). In some embodiments, the support contains the solidifiable material.

[0106] According to some embodiments, the system comprises an optical path between the source and the precursor, when present. For example, referring to FIG. 1A, system 102a comprises optical path 112 (e.g., optical path 112a and 112b) between source 104 and precursor 110, when present.

[0107] Although FIG. 1A schematically illustrates optical path 112 between source 104 and precursor 110 as a straight line, it should be appreciated that the optical path is not limited to the configuration shown. For example, as would generally be understood by a person of ordinary skill in the art, in various embodiments, the optical path between the source and the precursor, when present, may follow any of a number of suitable pathways, which may be altered, redirected, or otherwise influenced by one or more optical components of the system (e.g., lenses, mirrors, beam splitters, filters, or other optical elements).

[0108] In certain embodiments, the system comprises a homogenizer of the electromagnetic radiation pattern. According to some embodiments, the homogenizer is configured to at least partially homogenize the electromagnetic radiation pattern. For example, referring to FIG. 1A, system 102a comprises homogenizer 106a configured to at least partially homogenize electromagnetic radiation pattern 114. As used herein, the term “homogenize,” with respect to an electromagnetic radiation pattern, refers to altering the electromagnetic radiation pattern so that it exhibits a more uniform spatial and / or a broader angular distribution of intensity across a plurality of regions (e.g., pixels). As shown in FIG. 1A, homogenizer 104 at least partially homogenizes electromagnetic radiation pattern 114a to produce at least partially homogenized electromagnetic radiation pattern 114b. As described herein in greater detail, at least partially homogenizing the electromagnetic radiation pattern advantageously distributes an intensity of the electromagnetic radiation pattern more uniformly across a plurality of regions, which reduces defects and / or inconsistencies in products manufactured using the systems and / or methods described herein.

[0109] #14469326vl FIG. IB shows, in accordance with certain embodiments, schematic diagrams of different types of electromagnetic radiation pattern homogenization, corresponding to box IB in FIG. 1A representing the center ray of electromagnetic radiation incident to homogenizer 106. While FIG. IB schematically represents behavior of the center ray of electromagnetic radiation incident to homogenizer 106, it should be understood that the embodiments shown are applicable to other rays incident to homogenizer 106, including, for example, marginal rays incident to one or more peripheral portions of the homogenizer.

[0110] In certain embodiments, the homogenizer is configured to at least partially homogenize the electromagnetic radiation pattern to produce an at least partially homogenized electromagnetic radiation pattern that is laterally translated. For example, referring to FIG. IB, in system 102a’, homogenizer 106 is configured to at least partially homogenize electromagnetic radiation pattern 114a to produce at least partially homogenized electromagnetic radiation pattern 114b’ that is laterally translated. In some embodiments, the homogenizer is configured to at least partially homogenize the electromagnetic radiation pattern to produce an at least partially homogenized electromagnetic radiation pattern that results in crossover. For example, referring to FIG. IB, in system 102a”, homogenizer 106 is configured to at least partially homogenize electromagnetic radiation pattern 114a to produce at least partially homogenized electromagnetic radiation pattern 114b”, which exhibits crossover. In certain embodiments, the homogenizer is configured to at least partially homogenize the electromagnetic radiation pattern to produce an at least partially homogenized electromagnetic pattern that is angularly translated. Referring, for example, to FIG. IB, in system 102a”, homogenizer 106 is configured to at least partially homogenize electromagnetic radiation pattern 114a to produce at least partially homogenized electromagnetic radiation pattern 114b’” that is angularly translated. Homogenization of electromagnetic radiation illustrated in the figures described herein is schematically represented in the manner shown in FIG. 1A. However, it should be understood that the embodiments of homogenization illustrated in FIG. IB (e.g., lateral displacement, crossover, angular displacement, and / or any combination thereof) may be applied to any of the figures described herein.

[0111] In some embodiments, the homogenizer is positioned in association with the optical path between the source and the precursor, when present. Referring, for example, to FIG. 1A, homogenizer 106a is positioned in association with optical path 112 (e.g., optical path 112a and 112b) between source 104 and precursor 110, when present. The homogenizer may be positioned in any of a variety of suitable locations in association with the optical path between the source and the precursor, as described herein in greater detail.

[0112] #14469326vl According to certain embodiments, the homogenizer is an article movable between at least two positions. In some embodiments, movement of the homogenizer between the at least two positions at least partially homogenizes the electromagnetic radiation pattern.

[0113] In certain embodiments, the homogenizer is angularly displaceable relative to an optical axis of the electromagnetic radiation pattern incident to the homogenizer. Referring, for example, to FIG. 1A, homogenizer 106a is angularly displaceable relative to optical axis 120 of electromagnetic radiation pattern 114a incident to homogenizer 106a. As used herein, the term “angularly displaceable,” relative to an optical axis of an incident electromagnetic radiation pattern, refers to the capability of the homogenizer to undergo a change in angular orientation relative to the optical axis of the incident electromagnetic radiation pattern. As described herein in greater detail herein, such displacement may be rotation of the homogenizer relative to the optical axis of the incident electromagnetic radiation pattern and / or titling of the homogenizer relative to the optical axis of the incident electromagnetic radiation pattern. In some embodiments, the homogenizer is configured to at least partially homogenize the electromagnetic radiation pattern when undergoing angular displacement.

[0114] In certain embodiments, although not shown in the figures, the optical axis of the electromagnetic radiation pattern incident to the homogenizer is offset from the center of the electromagnetic radiation emitted by the source.

[0115] In some embodiments, the type of movement, the location, and / or the properties of the homogenizer are selected in connection with a spatial light modulator (e.g., pixel generator) and optical lens assembly elements. In certain embodiments, the homogenizer is placed between the optical lens assembly and the pixel generator, inside the lens assembly between any of the lens elements (e.g., if the system is using a plano-convex lens or other optical element to make a projection lens into a telecentric lens), after the lens assembly elements and pixel generator, as part of the of the support within the optical path of the pixel generator, or between the support and the precursor.

[0116] According to some embodiments, the homogenizer is configured to alter rays of electromagnetic radiation based on one or more factors, including the number of homogenizers used, the type of diffuser, the inclusion or exclusion of a lens, the type of lens, the reflectivity of the homogenizer, the transparency of the homogenizer, and the movement type or lack of movement of the homogenizer or its components. Combinations of the aforementioned factors may cause the electromagnetic radiation incident to the homogenizer to shift in position, angle, or some combination of both.

[0117] #14469326vl The homogenization effect on pixels results from the location of the homogenizer(s) within the optical path. For example, if a flat sheet of glass functioning as the homogenizer is angularly displaced after the lens assembly, it will transpose the ray of electromagnetic radiation without adjusting the angle causing the pixel to move in the pattern of the homogenizer. As another example, when the homogenizer is placed inside a telecentric lens assembly, the translation of the ray of electromagnetic radiation may result in a combination of angular change of the ray along with a translation that defines a pivot point where the pixel is perfectly in focus. In the latter case, the pixel may not translate if the telecentric lens is in-focus at the plane of the precursor support. In these circumstances, uniform homogenization may not occur depending on the angle of the distribution from the homogenizer. To induce uniform homogenization, the precursor support may be altered such that it is positioned a distance from the in-focus plane of the telecentric lens. Changing the plane of the precursor support with respect to the in-focus plane of the telecentric lens creates variation in the location and angle for each pixel, resulting in a uniform homogenization of the pixel distribution. In some embodiments, the plane is moved a distance such that it is not aligned with the in-focus plane of the telecentric lens, but not a distance great enough such that the geometry of the patterned radiation becomes deformed when it interacts with the precursor.

[0118] Alternatively, the plane of the precursor support may remain aligned with the in-focus plane of the telecentric lens assembly, with an additional homogenizer positioned in the optical path of the telecentric lens between the lens assembly and the precursor support. In these embodiments, the homogenizer positioned between the lens assembly and the precursor support is desynchronized from the homogenizer positioned within the lens assembly in terms of angular displacement and speed of rotation. This is one of many examples of arrangements of homogenizer(s) within and around a lens assembly.

[0119] Different types of pixel homogenizations may be desirable for different applications. In certain embodiments, homogenizer(s) having reflective properties results in the inverse effect of transparent homogenizer(s). In certain embodiments, translating the position of a homogenizer comprising a transparent article positioned within a telecentric lens assembly results in angular translation of the pixels correlated to the distance of translation of the homogenizer. In certain embodiments, tilting the position of a homogenizer comprising a transparent article positioned within a telecentric lens assembly results in a linear translation of the pixels correlated with the direction and degree of tilt. In certain embodiments, tilting a reflective homogenizer within a telecentric lens assembly results in a linear translation of the pixels. In certain embodiments, translating a reflective homogenizer positioned between a lens assembly and a precursor support

[0120] #14469326vl results in angular displacement and lateral displacement of the pixels. With the benefit of this disclosure, it may be determined which type(s) of homogenization(s) may be most beneficial for a given photoreaction, for use with a given photoreaction precursor, or for producing a photoreaction product having specific properties.

[0121] According to some embodiments, the homogenizer is at least partially transparent to electromagnetic radiation and / or at least partially reflective of electromagnetic radiation.

[0122] In some embodiments, for example, the homogenizer is at least partially transparent to the electromagnetic radiation. Referring, for example, to FIG. 1A, homogenizer 106a is at least partially transparent to electromagnetic radiation (e.g., electromagnetic radiation pattern 114). In some embodiments, the homogenizer is at least partially transparent to UV and / or IR electromagnetic radiation. The homogenizer may, in some embodiments, permit transmission of at least a portion of the incident electromagnetic radiation through the homogenizer. The degree of transparency of the electromagnetic radiation may vary depending on the wavelength of the electromagnetic radiation, the material of the homogenizer, and / or the thickness of the homogenizer. In certain embodiments, for example, the homogenizer transmits substantially all the incident electromagnetic radiation (i.e., the homogenizer is substantially transparent), while in other embodiments the homogenizer may transmit only a portion of the incident electromagnetic radiation (e.g., the homogenizer is semi-transparent). In some embodiments, the homogenizer is configured to at least partially homogenize the electromagnetic radiation pattern when the electromagnetic radiation pattern passes through at least a portion of the homogenizer when undergoing angular displacement, as described herein in greater detail.

[0123] The homogenizer that is at least partially transparent to electromagnetic radiation may comprise any of a variety of suitable materials. In some embodiments, for example, the homogenizer comprises glass (e.g., a sheet or layer of glass). In some embodiments, the homogenizer comprises silica and / or quartz. In certain embodiments, the homogenizer comprises glass (e.g., silica and / or quartz), at least a portion of which is sandblasted (e.g., at least partially sandblasted glass). Other materials are also possible.

[0124] In certain embodiments, the homogenizer comprises a lens element. The lens element may, in some embodiments, comprise a concave curve and / or a convex curve. Suitable lens elements include, for example, piano, plano-concave, plano-convex, convex-convex, concave- convex, concave-concave, micro lens array, fish eve, fly s eye, flat sheet, and the like. In certain embodiments, the lens element comprises a telecentric lens. Other lens elements are also possible.

[0125] #14469326vl According to some embodiments, the homogenizer comprises a polymeric material, which may include a plastic material. Suitable polymeric and / or plastic materials include, but are not limited to, acrylic polymers, polymethyl methacrylate (PMMA), polycarbonate, thermoset polymers such as poly(allyl diglycol carbonate) (e.g., CR-39), Trivex®, and the like.

[0126] In certain embodiments, the homogenizer comprises a metalloid such as germanium. In some embodiments, the metalloid (e.g., germanium) is at least partially transparent to IR electromagnetic radiation.

[0127] In some embodiments, the homogenizer comprises a base substrate (e.g., a base substrate comprising any of the materials described above) at least partially coated with an anti-reflective material. The anti-reflective material may, in some embodiments, comprise a metal and / or a ceramic. In certain embodiments, the anti-reflective material is MgF2. Other anti-reflective materials are also possible.

[0128] According to certain embodiments, the homogenizer is at least partially reflective of electromagnetic radiation. FIG. 2A shows, in accordance with certain embodiments, a schematic diagram of system 102b comprising homogenizer 106b that is at least partially reflective of electromagnetic radiation (e.g., electromagnetic radiation pattern 114). The homogenizer may, in certain embodiments, reflect at least a portion of the incident electromagnetic radiation off the homogenizer. The degree of reflection of the electromagnetic radiation may vary depending on the wavelength of the electromagnetic radiation, the material of the homogenizer, and / or the thickness of the homogenizer. In some embodiments, for example, the homogenizer reflects substantially all the incident electromagnetic radiation (e.g., the homogenizer is substantially reflective), while in other embodiments, the homogenizer may reflect only a portion of the incident electromagnetic radiation (e.g., the homogenizer is semi- reflective). In some embodiments, the homogenizer is configured to at least partially homogenize the electromagnetic radiation pattern when the electromagnetic radiation pattern is reflected by at least a portion of the homogenizer when undergoing angular displacement.

[0129] The homogenizer that is at least partially reflective of electromagnetic radiation may comprise any of a variety of suitable materials. In certain embodiments, for example, the homogenizer comprises a metal (e.g., aluminum, silver, gold, copper, and the like), a ceramic, glass, and / or combinations thereof. In certain embodiments, the homogenizer comprises a composite material that is configured to reflect the electromagnetic radiation incident to the homogenizer. In some embodiments, the homogenizer comprises a base substrate at least partially coated with a reflective material, such as one or more of the metals described above. Other materials are also possible.

[0130] #14469326vl According to some embodiments, the homogenizer is rotatable relative to the optical axis of the electromagnetic radiation pattern incident to the homogenizer. For example, FIG. 1C shows, in accordance with certain embodiments, a schematic diagram of homogenizer 106a that is rotatable (e.g., via rotation 116) relative to optical axis 120 of electromagnetic radiation pattern 114a incident to homogenizer 106a. FIG. 2B shows, in accordance with certain embodiments, a schematic diagram of homogenizer 106b that is rotatable (e.g., via rotation 116) relative to optical axis 120 of electromagnetic radiation pattern 114a incident to homogenizer 106b.

[0131] In certain embodiments, the homogenizer is tiltable relative to the optical axis of the electromagnetic radiation pattern incident to the homogenizer. For example, FIG. ID shows, in accordance with certain embodiments, a schematic diagram of homogenizer 106a that is tiltable (e.g., via titling 118a and 118b) relative to optical axis 120 of electromagnetic radiation pattern 114a incident to homogenizer 106a. FIG. 2C shows, in accordance with certain embodiments, a schematic diagram of homogenizer 106b that is tiltable (e.g., via tilting 118a and 118b) relative to optical axis 120 of electromagnetic radiation pattern 114a incident to homogenizer 106b. Suitable tilting angles relative to the optical axis of the electromagnetic radiation pattern incident to the homogenizer are described herein in greater detail.

[0132] According to some embodiments, the homogenizer is rotatable relative to the optical axis of the electromagnetic radiation pattern incident to the homogenizer and tiltable relative to the optical axis of the electromagnetic radiation pattern incident to the homogenizer. For example, FIG. IE shows, in accordance with certain embodiments, a schematic diagram of homogenizer 106a that is rotatable (e.g., via rotation 116) relative to optical axis 120 of electromagnetic radiation pattern 114a incident to homogenizer 106a and tiltable (e.g., via tilting 118a and 118b) relative to optical axis 120 of electromagnetic radiation pattern 114a incident to homogenizer 106a. FIG. 2D shows, in accordance with certain embodiments, a schematic diagram of homogenizer 106b that is rotatable (e.g., via rotation 116) relative to optical axis 120 of electromagnetic radiation pattern 114a incident to homogenizer 106b and tiltable (e.g., via tilting 118a and 118b) relative to optical axis 120 of electromagnetic radiation pattern 114a incident to homogenizer 106b.

[0133] According to some embodiments, the homogenizer is further linearly displaceable relative to the optical axis of the electromagnetic radiation pattern incident to the homogenizer. For example, referring to FIGS. 1A and 2A, homogenizer 106 (e.g., homogenizer 106a and 106b) is further linearly displaceable (e.g., via linear displacement 134a and 134b) relative to

[0134] #14469326vl - 1 - optical axis 120 of electromagnetic radiation pattern 114a incident to homogenizer 106 (e.g., homogenizer 106a and 106b).

[0135] The homogenizer may have any of a variety of suitable thicknesses. Referring, for example, to FIG. 1A, homogenizer 106 (e.g., homogenizer 106a) has thickness 122. In certain embodiments, the thickness of the homogenizer is measured along a direction corresponding to an optical axis of the electromagnetic radiation pattern incident to the homogenizer. For example, referring to FIG. 1A, thickness 122 of homogenizer 106a is measured along a direction corresponding to optical axis 120 of electromagnetic radiation pattern 114a incident to homogenizer 106a.

[0136] In certain embodiments, the thickness of the homogenizer is substantially uniform across a surface of the homogenizer, the surface being perpendicular to the thickness. For example, in some embodiments, the homogenizer comprises a sheet or layer (e.g., of glass), and the thickness of the sheet or layer is substantially uniform across a surface of the sheet or layer, the surface of the sheet or layer perpendicular to the thickness of the sheet or layer. In other embodiments, the thickness of the homogenizer varies across a surface of the homogenizer. In certain embodiments, for example, the homogenizer comprises a lens element, and the thickness of the lens element varies across a surface of the lens element, the surface of the lens element perpendicular to the thickness of the lens element.

[0137] In some embodiments, the homogenizer has a thickness greater than or equal to 0.25 millimeters, greater than or equal to 0.5 millimeters, greater than or equal to 1 millimeter, greater than or equal to 2 millimeters, greater than or equal to 5 millimeters, greater than or equal to 10 millimeters, greater than or equal to 20 millimeters, greater than or equal to 30 millimeters, greater than or equal to 40 millimeters, greater than or equal to 50 millimeters, or greater. In certain embodiments, the homogenizer has a thickness less than or equal to 50 millimeters, less than or equal to 40 millimeters, less than or equal to 30 millimeters, less than or equal to 20 millimeters, less than or equal to 10 millimeters, less than or equal to 5 millimeters, less than or equal to 2 millimeters, less than or equal to 1 millimeter, or less than or equal to 0.5 millimeters. Combinations of the above recited ranges are possible (e.g., the homogenizer has a thickness greater than or equal to 0.25 millimeters and less than or equal to 50 millimeters). Other ranges are also possible.

[0138] In certain embodiments, the homogenizer is configured to at least partially diffuse the electromagnetic radiation pattern. As used herein, the term “diffuse”, with respect to an electromagnetic radiation pattern, refers to altering the electromagnetic radiation pattern so that it is scattered to exhibit a broader spatial and / or angular distribution of intensity across a

[0139] #14469326vl plurality of regions (e.g., pixels), thereby reducing directionality or sharpness of features in the pattern. FIG. 3 shows, in accordance with certain embodiments, a schematic diagram of system 102c comprising homogenizer 106c configured to at least partially diffuse electromagnetic radiation pattern 114a to produce an at least partially diffused electromagnetic radiation pattern.

[0140] The homogenizer may, in some embodiments, comprise a diffusing mask comprising a material that renders that homogenizer suitable to at least partially diffuse the electromagnetic radiation pattern.

[0141] In certain embodiments, at least a portion of the homogenizer has a relatively low haze so that electromagnetic radiation transmitted through the homogenizer is not excessively diffused. In certain embodiments, for example, at least a portion of the homogenizer has a haze less than or equal to 5%, less than or equal to 4.5%, less than or equal to 4%, less than or equal to 3.5%, or less than or equal to 3%,. In some embodiments, the homogenizer has a haze greater than or equal to 2%, greater than or equal to 3%, greater than or equal to 3.5%, greater than or equal to 4%, or greater than or equal to 4.5%. Combinations of the above recited ranges are possible (e.g., at least a portion of the homogenizer has a haze less than or equal to 5% and greater than or equal to 2%). Other ranges are possible. The haze of the homogenizer may be calculated in accordance with ASTM standard DI 003- 13 through the thickness of the homogenizer.

[0142] According to some embodiments, the homogenizer is configured to at least partially homogenize the electromagnetic radiation pattern and at least partially diffuse the electromagnetic radiation pattern. For example, referring to FIG. 3, homogenizer 106b is configured to at least partially homogenize electromagnetic radiation pattern 114a and at least partially diffuse electromagnetic radiation pattern 114a to produce at least partially homogenized and at least partially diffused electromagnetic radiation pattern 114c. In certain embodiments, homogenization of the electromagnetic radiation pattern provides a more uniform distribution of intensity across a plurality of regions (e.g., pixels), and diffusion of the electromagnetic radiation pattern provides scattering of the radiation across the plurality of regions (e.g., pixels). In some embodiments, homogenization and diffusion may be used in combination to produce an electromagnetic radiation pattern that is both spatially uniform and angularly broadened. Although not shown in FIG. 3, homogenizer 106c may be angularly displaceable (e.g., rotatable, tiltable) with respect to optical axis of electromagnetic radiation pattern 114a incident to homogenizer 106c, as described herein in greater detail with respect to FIGS. 1A-1E.

[0143] According to some embodiments, the homogenizer is positioned in association with the support. FIG. 4 shows, in accordance with certain embodiments, a schematic diagram of system

[0144] #14469326vl 102d comprising homogenizer 106d positioned in association with support 110. In some embodiments, the homogenizer positioned in association with the support is configured to at least partially homogenize the electromagnetic radiation pattern and / or at least partially diffuse the electromagnetic radiation pattern. Referring, for example, to FIG. 4, homogenizer 106d positioned in association with support 110 is configured to at least partially homogenize electromagnetic radiation pattern 114a and at least partially diffuse electromagnetic radiation pattern 114a to produce at least partially homogenized and at least partially diffused electromagnetic radiation pattern 114c.

[0145] In certain embodiments, the homogenizer (e.g., positioned in association with a support) comprises a fluid layer, such as a layer of liquid. The fluid layer may, in some embodiments, be flowable. The fluid layer (e.g., layer of liquid) may comprise any of a variety of suitable materials. In certain embodiments, for example, the fluid layer comprises an oil. The oil may be a fluorinated oil, such as perfluoropolyether copolymer, in accordance with certain embodiments. Other fluids and / or oils are also possible.

[0146] According to some embodiments, the homogenizer (e.g., positioned in association with a support) comprises a solid and / or a semi-solid. In certain embodiments, for example, the solid and / or semi-solid comprises a polymer and / or a gel. Suitable polymers and / or gels include, but are not limited to, polydimethylsiloxane (PDMS), agarose gel, and / or fluorinated ethylene propylene (FEP) (e.g., a FEP thin film). Other polymers and / or gels are also possible.

[0147] In some embodiments, the fluid layer (e.g., the layer of liquid), the solid, and / or the semisolid comprises a plurality of particles dispersed within the respective medium. In some embodiments, the plurality of particles advantageously enhance diffusion of the electromagnetic radiation pattern. In certain embodiments, the plurality of particles comprises nanoparticles (e.g., having a maximum characteristic dimension greater than or equal to 1 nm and less than 1 micrometer). In some embodiments, the plurality of particles comprises microparticles (e.g., having a maximum characteristic dimension greater than or equal to 1 micrometer and less than 1 millimeter). Any of a variety of suitable particles may be utilized, including for example, TiCE, zirconia, zinc oxide, silica, and the like. In certain embodiments, the particle comprises a core shell structure with the outer shell being a polymer or any of the materials described above.

[0148] The systems described herein may comprise one or more additional components. According to some embodiments, for example, the system comprises a projection device. FIG. 5A shows, in accordance with certain embodiments, a schematic diagram of system 102e comprising homogenizer 106’ and one or more additional components.

[0149] #14469326vl According to certain embodiments, the system comprises a projection device. In some embodiments, the projection device is configured to project an electromagnetic radiation pattern from electromagnetic radiation emitted by the source. Referring, for example, to FIG. 5A, system 102e comprises projection device 124 configured to project electromagnetic radiation pattern 114a from electromagnetic radiation 115 emitted by source 104. In some embodiments, the source is associated with the projection device. For example, referring to FIG. 5A, source 104 is associated with projection device 124. The source may, for example, be a component of the projection device, in accordance with certain embodiments (e.g., as shown in FIG. 5A). In other embodiments, the source is external to the projection device.

[0150] According to some embodiments, the projection device comprises a projection lens. For example, referring to FIG. 5A, projection device 124 comprises projection lens 128.

[0151] In certain embodiments, the projection device is configured to blur the electromagnetic radiation pattern. As used herein, the term “blur”, with respect to an electromagnetic radiation pattern, refers to altering the electromagnetic radiation pattern so that boundaries between adjacent illuminated and non-illuminated regions (e.g., pixels) are broadened, thereby reducing sharpness or contrast of regions (e.g., pixels) in the pattern. In some embodiments, the electromagnetic radiation pattern is intentionally blurred by the projection device. In certain embodiments, telecentric and / or high etendue, low-depth-of-field projection will yield improved results in product manufacturing when blurring is applied, as there will be less image distortion for a given amount of blur.

[0152] According to some embodiments, the projection device is configured to defocus the electromagnetic radiation pattern. As used herein, the term “defocus”, with respect to an electromagnetic radiation pattern, refers to altering the electromagnetic radiation pattern by shifting the focal plane of the projection device relative to regions (e.g., pixels) in the pattern are not sharply focused on the projection target. In certain embodiments, the electromagnetic radiation pattern is intentionally defocused by the projection device.

[0153] According to some embodiments, the system comprises a spatial light modulator (e.g., pixel generator). In certain embodiments, the spatial light modulator is configured to transmit and / or reflect the electromagnetic radiation from the source to the support. For example, as shown in FIG. 5A, system 102e comprises spatial light modulator 126 configured to transmit and / or reflect electromagnetic radiation 115 from source 104 to support 108. The spatial light modulator may, in certain embodiments, comprise a plurality of pixels. In some embodiments, electromagnetic radiation transmitted by and / or reflected off the spatial light modulator forms a corresponding plurality of pixels in the projected electromagnetic radiation pattern. Each pixel

[0154] #14469326vl of the plurality of pixels may have any of a variety of suitable sizes (e.g., characteristic dimensions). In some embodiments, for example, each pixel of the plurality of pixels has a size greater than or equal to 10 micrometers, greater than or equal to 20 micrometers, greater than or equal to 30 micrometers, or greater than or equal to 40 micrometers. In some embodiments, each pixel of the plurality of pixels has a size less than or equal to 50 micrometers, less than or equal to 40 micrometers, less than or equal to 30 micrometers, or less than or equal to 20 micrometers. Combinations of the above recited ranges are possible (e.g., each pixel of the plurality of pixels has a size greater than or equal to 10 micrometers and less than or equal to 50 micrometers). Other ranges are also possible.

[0155] In certain embodiments, the spatial light modulator is associated with the projection device. Referring, for example, to FIG. 5A, spatial light modulator 126 is associated with projection device 124. In some embodiments, the spatial light modulator is a component of the projection device (e.g., as shown in FIG. 5A). In other embodiments, the spatial light modulator is external to the projection device.

[0156] The spatial light modulator may comprise any of a variety of suitable devices. In certain embodiments, for example, the spatial light modulator comprises a digital micromirror device (DMD). In some embodiments, the spatial light modulator comprises a liquid crystal display (LCD). Other spatial light modulators are also possible.

[0157] In certain embodiments, the spatial light modulator is positioned along the optical path between the source and the precursor, when present. For example, referring to FIG. 5A, spatial light modulator 126 is positioned along optical path 112 (e.g., optical path 112a’, 112a, 112b, and 112b’) between source 104 and precursor 110. In some embodiments, the homogenizer is positioned between the spatial light modulator and the support. As shown, for example, in FIG. 5A, homogenizer 106’ is positioned between spatial light modulator 126 and support 108 (e.g., along optical path 112).

[0158] In some embodiments, although not shown in the figures, the homogenizer is associated with the projection device. In some embodiments, for example, the homogenizer is a component of the projection device.

[0159] According to certain embodiments, the system comprises a collimator configured to collimate the electromagnetic radiation pattern incident to the collimator. The collimator may be or comprise, in certain embodiments, a collimating lens. Referring, for example, to FIG. 5A, system 102e comprises collimator 130 (e.g., collimating lens) configured to collimate electromagnetic radiation pattern 114a incident to collimator 130.

[0160] #14469326vl In some embodiments, the collimator is positioned along the optical path between the source and the precursor, when present. For example, referring to FIG. 5 A, collimator 130 is positioned along optical path 112 (e.g., optical path 112a’, 112a, 112b, and 112b’) between source 104 and precursor 110. In certain embodiments, the collimator is positioned between the homogenizer and the precursor, when present. As shown, for example, in FIG. 5A, collimator 130 is positioned between homogenizer 106’ and precursor 110 (e.g., along optical path 112). In certain embodiments, positioning the collimator between the homogenizer and the precursor, when present, advantageously allows the homogenizer to alter an angular distribution of the electromagnetic radiation and the collimator to further alter the electromagnetic radiation into a more uniform spatial profile for delivery to the projection target.

[0161] According to some embodiments, the system comprises at least two homogenizers (e.g., three homogenizers, four homogenizers, five homogenizers, etc.) positioned in association with the optical path between the source and the precursor, when present. FIG. 5B shows, in accordance with certain embodiments, a schematic diagram of system 102f comprising at least two homogenizers 106 (e.g., homogenizer 106’ and 106”). In certain embodiments, for example, the at least two homogenizers are positioned in series along the optical path between the source and the precursor. Referring, for example, to FIG. 5B, the at least two homogenizers 106 (e.g., homogenizer 106’ and 106”) are positioned in series along optical path 112 (e.g., optical path 112a’, 112a, 112b, 112b’, and 112b”). In some embodiments, each homogenizer may be configured to at least partially homogenize and / or at least partially diffuse the electromagnetic radiation pattern. For example, referring to FIG. 5B, homogenizer 106’ is configured to at least partially homogenize and / or at least partially diffuse electromagnetic radiation pattern 114a (e.g., to produce at least partially homogenized electromagnetic radiation pattern 114b), and homogenizer 106” is configured to at least partially homogenize and / or at least partially diffuse electromagnetic radiation pattern 114b (e.g., to produce at least partially homogenized electromagnetic radiation pattern 114b*).

[0162] In certain embodiments, the collimator is positioned between at least two homogenizers. Referring, for example, to FIG. 5B, collimator 130 is positioned between at least two homogenizers 106 (e.g., between homogenizer 106’ and homogenizer 106”). In certain embodiments, positioning collimator 130 between at least two homogenizers 106 advantageously allows homogenizer 106’ to alter an angular distribution of the electromagnetic radiation, collimator 130 to further alter the electromagnetic radiation into a more uniform spatial profile, and homogenizer 106” to further alter a lateral displacement of the electromagnetic radiation for delivery to the projection target.

[0163] #14469326vl According to some embodiments, the system may comprise a first homogenizer and a second homogenizer, wherein at least one of the homogenizers is positioned in association with the support.

[0164] According to some embodiments, the system comprises one or more motors configured to control an angular and / or linear displacement of the homogenizer. In certain embodiments, the system comprises one or more actuators configured to control an angular and / or linear displacement of the transparent article. For example, referring to FIG. 5A, system 102e comprises motor and / or actuator 132 configured to control an angular and / or linear displacement of homogenizer 106’.

[0165] The systems described herein may comprise one more components not shown in the figures, including, for example, one or more lenses (e.g., telecentric lenses), mirrors, beam splitters, filters, de-specklers, polarizers, or other optical elements.

[0166] According to some embodiments, although not shown in the figures, the systems described herein may comprise a substrate on which one or more layers of a product of a photochemical reaction are deposited. In certain embodiments, the substrate is a build platform that is associated with the support configured to contain the precursor. The substrate (e.g., build platform) may be associated with a Z-arm configured to adjust a position of the build platform along a Z-axis.

[0167] According to certain embodiments, one or more of the additional components described herein may be utilized in any of systems 102a-102f shown in FIGS. 1A-5B.

[0168] The systems described herein may be or comprise any of a variety of systems and / or devices. In certain embodiments, the system is an additive manufacturing device. For example, in some embodiments, the system is a 3D printer (e.g., a digital light processing 3D printer). Other systems and / or devices are also possible, including, for example, 2D printers, lithography printing systems, and the like). Other systems and / or devices are also possible.

[0169] According to certain embodiments, methods are described. In some embodiments, a method comprises emitting electromagnetic radiation from a source. In certain embodiments, as described herein in greater detail, the electromagnetic radiation comprises an electromagnetic radiation pattern. Referring, for example, to FIGS. 1A-2D, the method comprises emitting electromagnetic radiation comprising electromagnetic radiation pattern 114a from source 104.

[0170] In some embodiments, the method comprises at least partially homogenizing the electromagnetic radiation pattern to produce an at least partially homogenized electromagnetic radiation pattern. For example, referring to FIGS. 1A-2D, the method comprises at least

[0171] #14469326vl partially homogenizing electromagnetic radiation pattern 114a to produce an at least partially homogenized electromagnetic radiation pattern 114b.

[0172] According to some embodiments, at least partially homogenizing the electromagnetic radiation pattern is performed with a homogenizer. Referring, for example, to FIGS. 1A-2D, at least partially homogenizing electromagnetic radiation pattern 114a (e.g., to produce at least partially homogenized electromagnetic radiation pattern 114b) is performed with homogenizer 106 (e.g., homogenizer 106a and 106b).

[0173] In some embodiments, the method comprises moving the homogenizer between at least two positions to produce the at least partially homogenized electromagnetic pattern. In certain embodiments, the method comprises angularly displacing the homogenizer relative to an optical axis of the electromagnetic radiation pattern incident to the homogenizer to produce the at least partially homogenized electromagnetic radiation pattern. For example, referring to FIGS. 1C-1E and 2B-2D, the method comprises angularly displacing homogenizer 106 (e.g., homogenizer 106a and 106b) relative to optical axis 120 of electromagnetic radiation pattern 114a incident to homogenizer 106 (e.g. homogenizer 106a and 106b) to produce at least partially homogenized electromagnetic radiation pattern 114b.

[0174] In some embodiments, angularly displacing the homogenizer comprises rotating the homogenizer relative to the optical axis of the electromagnetic radiation pattern incident to the homogenizer. For example, referring to FIGS. 1C, IE, 2B, and 2D, the method comprises rotating (e.g., via rotation 116) homogenizer 106 (e.g., homogenizer 106a and 106b) relative to optical axis 120 of electromagnetic radiation pattern 114a incident to homogenizer 106 (e.g., homogenizer 106a and 106b).

[0175] The homogenizer may be rotated at any of a variety of suitable speeds. In some embodiments, for example, rotating the homogenizer comprises rotating the homogenizer at a speed greater than or equal to 1 Hz, greater than or equal to 10 Hz, greater than or equal to 50 Hz, greater than or equal to 100 Hz, greater than or equal to 150 Hz, greater than or equal to 200

[0176] Hz, greater than or equal to 250 Hz, greater than or equal to 300 Hz, greater than or equal to 350

[0177] Hz, greater than or equal to 400 Hz, greater than or equal to 450 Hz, greater than or equal to 500

[0178] Hz, or greater, relative to the optical axis of the electromagnetic radiation pattern incident to the homogenizer. In certain embodiments, rotating the homogenizer comprises rotating the homogenizer at a speed less than or equal to 500 Hz, less than or equal to 450 Hz, less than or equal to 400 Hz, less than or equal to 350 Hz, less than or equal to 300 Hz, less than or equal to 250 Hz, less than or equal to 200 Hz, less than or equal to 150 Hz, less than or equal to 100 Hz, less than or equal to 50 Hz, or less than or equal to 10 Hz, relative to the optical axis of the

[0179] #14469326vl electromagnetic radiation pattern incident to the homogenizer. Combinations of the above recited ranges are possible (e.g., rotating the homogenizer comprise rotating the homogenizer at a speed greater than or equal to 1 Hz and less than or equal to 500 Hz relative to the optical axis of the electromagnetic radiation pattern incident to the homogenizer, rotating the homogenizer comprises rotating the homogenizer at a speed greater than or equal to 150 Hz and less than or equal to 450 Hz relative to the optical axis of the electromagnetic radiation pattern incident to the homogenizer). Other ranges are also possible.

[0180] According to some embodiments, angularly displacing the homogenizer comprises titling the homogenizer relative to the optical axis of the electromagnetic radiation pattern incident to the homogenizer. Referring, for example, to FIGS. ID- IE and 2C-2D, the method comprises tilting (e.g., via tilting 118a and 118b) homogenizer 106 (e.g., homogenizer 106a and 106b) relative to optical axis 120 of electromagnetic radiation pattern 114a incident to homogenizer 106 (e.g., homogenizer 106a and 106b).

[0181] The homogenizer may be tilted at any of a variety of suitable angles. Referring, for example, to FIGS. 1D-1E and 2C-2D, tilting homogenizer 106 (e.g., 106a and 106b) comprises tiling homogenizer 106 (e.g., homogenizer 106a and 106b) at angle 132 relative to optical axis 120 of electromagnetic radiation pattern 114a incident to homogenizer 106 (e.g., homogenizer 106a and 106b). In some embodiments, tilting the homogenizer comprises tilting the homogenizer at an angle greater than or equal to 1 °, greater than or equal to 2 °, greater than or equal to 3 °, greater than or equal to 4 °, greater than or equal to 5 °, greater than or equal to 6 °, greater than or equal to 7 °, greater than or equal to 8 °, or greater than or equal to 9 °, relative to the optical axis of the electromagnetic radiation pattern incident to the homogenizer. In some embodiments, tilting the homogenizer comprises tilting the homogenizer at an angle less than or equal to 10 °, less than or equal to 9 °, less than or equal to 8 °, less than or equal to 7 °, less than or equal to 6 °, less than or equal to 5 °, less than or equal to 4 °, less than or equal to 3 °, or less than or equal to 2 ° relative to the optical axis of the electromagnetic radiation pattern incident to the homogenizer. Combinations of the above recited ranges are possible (e.g., tiling the homogenizer comprises tilting the homogenizer at an angle greater than or equal to 1 ° and less than or equal to 10 ° relative to the optical axis of the electromagnetic radiation pattern incident to the homogenizer, tilting the homogenizer comprise titling the homogenizer at an angle greater than or equal to 2 ° and less than or equal to 5 ° relative to the optical axis of the electromagnetic radiation pattern incident to the homogenizer. Other ranges are also possible.

[0182] #14469326vl In some embodiments, as described herein in greater detail, the homogenizer is at least partially transparent to the electromagnetic radiation and / or at least partially reflective of the electromagnetic radiation.

[0183] In certain embodiments, for example, the homogenizer is at least partially transparent to the electromagnetic radiation. In some such embodiments, at least partially homogenizing the electromagnetic radiation pattern comprises passing the electromagnetic radiation pattern through at least a portion of the homogenizer while angularly displacing the homogenizer. Referring, for example, to FIGS. 1C-1E, at least partially homogenizing electromagnetic radiation pattern 114a comprises passing electromagnetic radiation pattern 114a through at least a portion of homogenizer 106a while angularly displacing homogenizer 106a.

[0184] In some embodiments, the homogenizer is at least partially reflective of the electromagnetic radiation. In some such embodiments, at least partially homogenizing the electromagnetic radiation pattern comprises reflecting the electromagnetic radiation pattern off at least a portion of the homogenizer while angularly displacing the homogenizer. For example, referring to FIGS. 2B-2D, at least partially homogenizing electromagnetic radiation pattern 114a comprises reflecting electromagnetic radiation pattern 114a off at least a portion of homogenizer 106b while angularly displacing homogenizer 106b.

[0185] According to certain embodiments, at least partially homogenizing the electromagnetic radiation pattern is performed by a component controlled via a processor executing instructions to produce the at least partially homogenized electromagnetic radiation pattern. In some embodiments, the component lacks a dedicated homogenizing functionality.

[0186] According to some embodiments, at least partially homogenizing the electromagnetic radiation pattern comprises shifting one or more pixel positions of the electromagnetic radiation pattern. In some embodiments, the degree of shift of the one or more pixel positions may be any of a variety of suitable values. In some embodiments, the degree of shift of the one or more pixel positions is greater than or equal to a gap between two neighboring pixels in a plurality of pixels. For example, in some embodiments, the gap between two neighboring pixels in a plurality of pixels is about 10% of the size (e.g., characteristic dimension) of the pixel. As a representative embodiment, if the size (e.g., characteristic dimension) of a pixel in a plurality of pixels is 50 micrometers, then the gap between two neighboring pixels in the plurality of pixels is 5 micrometers. In some such embodiments, the degree of shift of the one or more pixel positions is greater than or equal to 5 micrometers.

[0187] In certain embodiments, the degree of shift of the one or more pixel positions, based on a pixel size greater than or equal to 10 micrometers and less than or equal to 50 micrometers, is

[0188] #14469326vl greater than or equal to 1 micrometer, greater than or equal to 5 micrometers, greater than or equal to 10 micrometers, greater than or equal to 20 micrometers, greater than or equal to 30 micrometers, greater than or equal to 40 micrometers, greater than or equal to 50 micrometers, greater than or equal to 60 micrometers, greater than or equal to 70 micrometers, greater than or equal to 80 micrometers, greater than or equal to 90 micrometers, greater than or equal to 100 micrometers, or greater. In some embodiments, the degree of shift of the one more pixel positions, based on a pixel size greater than or equal to 10 micrometers and less than or equal to 50 micrometers, is less than or equal to 100 micrometers, less than or equal to 90 micrometers, less than or equal to 80 micrometers, less than or equal to 70 micrometers, less than or equal to 60 micrometers, less than or equal to 50 micrometers, less than or equal to 40 micrometers, less than or equal to 30 micrometers, less than or equal to 20 micrometers, less than or equal to 10 micrometers, or less than or equal to 5 micrometers. Combinations of the above recited ranges are possible (e.g., the degree of shift of the one or more pixel positions, based on a pixel size greater than or equal to 10 micrometers and less than or equal to 50 micrometers, is greater than or equal to 1 micrometers and less than or equal to 100 micrometers). Other ranges are also possible. In certain embodiments, the degree of shift of the one or more pixel positions is determined according to Snell’s law (e.g., for a homogenizer that is transparent to electromagnetic radiation) or the law of reflection (for a homogenizer that is reflective of electromagnetic radiation).

[0189] In certain embodiments, the method comprises directing the at least partially homogenized electromagnetic radiation pattern at a precursor of a photochemical reaction. For example, referring to FIGS. 1A-2D, the method comprises directing at least partially homogenized electromagnetic radiation pattern 114b at precursor 110. In some embodiments, the method comprises carrying out a photochemical reaction initiated at least in part by the at least partially homogenized electromagnetic pattern.

[0190] According to some embodiments, the method comprises manufacturing an article and / or a product from the photochemical reaction. Any of a variety of suitable articles and / or products may be manufactured using the methods described herein. In some embodiments, for example, the article and / or product is an optical lens. Other articles and / or products are also possible and are described herein in greater detail.

[0191] According to certain embodiments, a system described herein comprises a source of electromagnetic radiation. For example, FIG. 6 shows another embodiment of the system with common elements of FIG. 1 A omitted for clarity. Dashed line 652 is shown to indicate that controller 650 is communicatively coupled with respective components of the depicted system

[0192] #14469326vl and / or actuators that affect their operation. According to various embodiments, controller 650 is configured to communicate with actuators to operate respective elements of the system as discussed, and / or communicate with digital controllers, firmware, and / or software, associated with the respective elements to modify, update, alter, or manage operative control parameters of the respective digital elements (e.g., actuator controls, control parameters of a pixel generator or pixel shifter, including, for example, properties of pixel generation, angle of homogenizer, speed of rotation, refresh rate, movement pattern, pixel shifter positioning, movement, timing, shit pattern, etc.). In various embodiments, operating software and / or firmware associated with known high-contrast projection systems are modified to enable additional movement characteristics (e.g., for pixel shifters), additional emission properties for pixel generators (e.g., varying intensity, pixel generation characteristics, etc.).

[0193] Various high-contrast projectors (an example source) are available that may contain a number of physical pixels insufficient to achieve high-resolution projection based on the available physical pixels. However, using a pixel generator and a pixel shifter (e.g., DMD and glass platter, or LCD, etc.), respective pixels in a source are rapidly shifted, allowing each one to do the job of multiple pixels. In essence, the illusion of a higher resolution projection is generated. A refresh rate for the projection can be selected (e.g., faster is better) so that any shifting is done so fast that it fools human eyes into seeing up to multiple times the projector’s native resolution without perceivable artifacts.

[0194] Shown in FIG. 7 is an example block diagram, and source 702 that emits ER through a number of lenses 704 and prism 706 so that a pixel generator 708 (e.g., DMD, LCD, etc.), in conjunction with a pixel shifter (e.g., movable glass plate, LCD, etc.) 710 can shift source pixel emissions into multiple positions on a projection via a projection lens 712. Given an example where the source provides 1080p resolution, moving the pixel shifter 710 to an angle relative to the optical path slightly shifts the whole image. In some examples, the shift is based on pixel size ~10 microns, and the resulting shifting can occur at up to 5 microns.

[0195] In high contrast settings (contrary to current usage), the shift positions target four different and distinct locations, resulting in four shifts that allow one pixel to appear to the human eye like four pixels. Conventional projectors that are configured for high contrast can include a controller board, a motherboard, and respective drivers that manage projection properties to ensure high contrast shift pixels are generated. Lor example, a high contrast projection system is configured to perfectly sync the operation of the pixel generator and the pixel shifter (e.g., any movement) so that only when the pixel shifter is in a location of one of the four shift pixel targets does the duty refresh perfectly sync up with the source and / or pixel

[0196] #14469326vl generator. Utilizing that perfect synchronization, the result is four crystal clear pixels out of a single pixel.

[0197] According to various embodiments, by varying the operating properties (e.g., respective positioning of pixel shifter, emission timing, refresh rate, duty refresh cycle, etc.) from those synchronization settings, the crystal clear pixels in the projection become more homogeneous. The gaps between pixels of high contrast approaches can be covered by emission energy, and the Gaussian distribution of energy in respective pixel locations can also be homogenized.

[0198] According to some examples, the operation of a projector (e.g., source), the pixel generator, and / or the pixel shifter are purposely executed out of sync with high-contrast imaging. In one example, the source is operated during the movement of the pixel shifter, resulting in a sweeping projection over what would otherwise be the gap space between pixels, and in other examples, the projection can also include overlap on adjacent pixel positions.

[0199] Various embodiments increase intensity homogenization in the projection based on decoupling the perfectly synchronized operation of high-contrast projection modes, and create a new mode operation for such systems that operates in opposition to high contrast configurations. In one example, a motherboard of the projector system is configured to control known pixel generator and pixel shifter components, to achieve a decoupling from synchronized operation. Then, by inputting 1080p data, the decoupled operation results in uniformity of intensity relative to high contrast operation modes. In other embodiments, high contrast parameters can be adjusted in the four shift per pixel mode (e.g., provide by various known high contrast projectors) to result in desynchronized operation. For example, by altering the control parameters, pixel generation timing (e.g., via on and off positioning or settings of pixel generators) will occur so that the pixelated emissions are shifted during the movement of the pixel shifter. Various movement patterns can be programmed and / or executed using pixel shifters, and include linear reciprocating motion, Epitrochoid, “Figure 8,” Lissajous curve, Circle, X and Y both having independent reciprocating motions that have different frequencies from each other, X and Y axial motion both having independent reciprocating motions where the magnitude of the motion is non-constant, among other examples. Various embodiments include a controller configured to send control signals to actuators in any pixel shifters so that the various patterns of movement are used, and result in homogenized emission patterns.

[0200] According to some embodiments, the lenses shown at 704 and / or projection lens 712 can be used to vary the focus of a resulting projection. By offsetting the focal plane of the projection, the energy incident on a projection target can be homogenized. Focus adjustment

[0201] #14469326vl can be used alone and / or in addition to the operations of the pixel shifter, and desynchronized operation of the source, pixel generator, and / or pixel shifter to achieve homogenization.

[0202] In some examples, specific lens types can also affect the homogenization of a projection. For example, various embodiments can implement a telecentric lens at 712. According to one embodiment, when a telecentric lens is used, rather than displacing the whole image with no changes in ray angles, the result is displacement of the image in a way that it moves the projected rays. This change in ray angle can be leveraged in various embodiments to improve homogenization .

[0203] In various embodiments, once pixel shifters are given operating parameters that override high contrast modes, they operate as homogenizers, and any functionality described with respect to a homogenizer can likewise be implemented in an augmented pixel shifter.

[0204] Additionally, an illustrative implementation of a special-purpose computer system 800 that can be used in connection with any of the embodiments of the disclosure provided herein is shown in FIG. 8. The computer system 800 shown is specially programmed to improve over known systems. The computer system 800 may include one or more processors 810 and one or more articles of manufacture that comprise non-transitory computer-readable storage media (e.g., memory 820 and one or more non-volatile storage media 830). The processor 810 may control writing data to and reading data from the memory 820 and the non-volatile storage device 830 in any suitable manner. In some embodiments, the controller of FIG. 6 can be implemented as a special purpose computer system 800, as an FPGA, and / or as an ASIC. In other embodiment, computer system 800 can communicate any references control signal, communicate operating parameters to described components, among other options.

[0205] According to some embodiments, the computer system can perform any of the functionality described herein, alone or in conjunction with the communication of control signals to other components (e.g., actuators, motors, vibrational elements, voice coils, etc.). In various examples, the computer system and / or control signals can be communicated to various components collectively, individually, and / or in any combination, for example, to impact the positioning of homogenization elements or change operating parameters. According to various embodiments, control signals are operable to alter the positioning of the discussed example homogenizers, transparent elements, transparent articles, spatial light modulators, digital micromirror devices, reflective articles, etc., based on exerting a mechanical influence via any actuator, motor, vibration-inducing component, etc. According to various embodiments, the result of any control signal is to induce changes in any one or more and any combination of:

[0206] #14469326vl angular displacement, emission pattern, rotation, speed of rotation, tilt, linear displacement, etc. of the system elements (e.g., described above).

[0207] In various examples, the processor 810 may execute one or more processor-executable instructions stored in one or more non-transitory computer-readable storage media (e.g., the memory 820), which may serve as non-transitory computer-readable storage media storing processor-executable instructions for execution by the processor 810. Such processorexecutable instruction can be configured to update operating parameters of pixel generators, pixel shifters, control emissions of a course, update firmware to enable programmatic control of pixel generators, pixel shifters, and respective operating parameters as discussed herein, among other options.

[0208] The terms “program” or “software” or “app” are used herein in a generic sense to refer to any type of computer code or set of processor-executable instructions that can be employed to program a computer or other processor to implement various aspects of embodiments as discussed above. Additionally, it should be appreciated that according to one aspect, one or more computer programs that when executed perform methods of the disclosure provided herein need not reside on a single computer or processor, but may be distributed in a modular fashion among different computers or processors to implement various aspects of the disclosure provided herein.

[0209] Processor-executable instructions may be in many forms, such as program modules, executed by one or more computers or other devices. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Typically, the functionality of the program modules may be combined or distributed as desired in various embodiments.

[0210] Also, data structures may be stored in one or more non-transitory computer-readable storage media in any suitable form. For simplicity of illustration, data structures may be shown to have fields that are related through location in the data structure. Such relationships may likewise be achieved by assigning storage for the fields with locations in a non-transitory computer-readable medium that convey relationships between the fields. However, any suitable mechanism may be used to establish relationships among information in fields of a data structure, including through the use of pointers, tags or other mechanisms that establish relationships among data elements.

[0211] Also, various inventive concepts may be embodied as one or more processes, of which examples have been provided. The acts performed as part of each process may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an

[0212] #14469326vl order different than illustrated, which may include performing some acts simultaneously, even though shown as sequential acts in illustrative embodiments.

[0213] The systems and / or methods described herein may be used to manufacture products and / or articles having advantageous properties as compared to products manufactured using conventional systems and / or methods. The advantageous properties may, in some embodiments, be associated with the homogenization of electromagnetic radiation described herein.

[0214] According to certain embodiments, an article made by 3D printing is described herein. The article may, in some embodiments, comprise internal features exhibiting controlled material variations. In some embodiments, the article comprises at least two non-parallel lines within the article. In some embodiments, each line exhibits a change in refractive index, density, and / or modulus along its length, and the change measured along one line differs from that of the other line by a defined threshold. Such differences can provide useful anisotropic or directional properties within the 3D printed article, for example for optical applications.

[0215] In certain embodiments, a change in the refractive index, the density, and / or the modulus along a distance of at least 1 mm of each of the at least two non-parallel lines differs from a change in refractive index, density, and / or modulus along at least 1 mm of the other line by at least 5%, at least 10%, at least 20%, or more.

[0216] In certain embodiments, the distance may be any of a variety of suitable distances. In certain embodiments, for example, the distance is least 2 mm, at least 5 mm, at least 10 mm, or at least 50 mm.

[0217] According to some embodiments, the at least two non-parallel lines are offset by at least 1 degree. For example, in certain embodiments, the at least two non-parallel lines are offset by at least 5 degrees, at least 10 degrees, or at least 15 degrees. In certain embodiments, the at least two non-parallel lines are substantially perpendicular (i.e., within + / - 5 degrees of perpendicular).

[0218] In certain embodiments, an article made by 3D printing comprises no line within the article which, along a distance of at least 1 mm (e.g., at least 2 mm, at least 5 mm, at least 10 mm, or at least 50 mm), is there a change in refractive index, density, and / or modulus of more than 1%. In certain embodiments, the article comprises no line within the article which, along a distance of at least 1 mm (e.g., at least 2 mm, at least 5 mm, at least 10 mm, or at least 50 mm), is the change in refractive index, density, and / or modulus more than 0.05%, more than 0.001%, more than 0.0005%, or more than 0.0001%. In certain embodiments, the article comprises no line within the article which, along a distance of at least 1 mm (e.g., at least 2 mm, at least 5 mm,

[0219] #14469326vl at least 10 mm, or at least 50 mm) is the change in refractive index more than 0.05%, more than 0.001%, more than 0.0001%, or more than 0.00001%.

[0220] The change in refractive index may be measured using a Hartmann- Shack wavefront sensor, by Raman spectroscopy, and / or by methods described in Tayama, G.T., Parant, P., Messaddeq, S.H. et al, Optical homogeneity and anisotropy of 3D printed silicate-aluminum- phosphate hybrid sol-gel materials via laser scan vat-photopolymerization, J Sol-Gel Sci Technol (2025), which is incorporated herein by reference in its entirety. Each method is suitable for providing a quantitative determination of refractive index variation within a margin of error of approximately + / - 5%. The change in density and / or modulus may be measured using atomic force microscopy (AFM), for example a Bruker AFM operated in PeakForce Tapping® mode.

[0221] According to some embodiments, the 3D printed article is an optical lens. Other articles are also possible.

[0222] U.S. Provisional Patent Application No. 63 / 703,101, filed October 3, 2024, and entitled “PROJECTOR ATTACHMENT APPARATUS FOR RANDOMIZING EMISSION,” and U.S. Provisional Patent Application No. 63 / 814,595, filed May 30, 2025, entitled “PROJECTOR ATTACHMENT APPARATUS FOR RANDOMIZING EMISSION,” are incorporated herein by reference in their entirety for all purposes.

[0223] The following example is intended to illustrate certain embodiments of the present disclosure, but does not exemplify the full scope of the disclosure.

[0224] EXAMPLE

[0225] FIG. 9 illustrates a projection of pixels resulting from a DMD within a projector suitable for 3D printing. The array of DMD further comprise pixel lines. As can be seen in FIG. 9, blurring occurs within the pixel gaps as some overlap occurs from a micromirror into the gap. As a result of this inconsistent distribution of energy within the gaps, inconsistent curing can occur within the areas of the product to be solidified by the ER within these gaps. In an embodiment, the object of the present disclosure is to translate the ER projection resulting from a pixel array randomly over a given area. Over time, random translation over the given area will equalize the amount of time each sub-region within the area is exposed to center of pixels and gaps between pixels. The result of random translation over time is an equivalent distribution of ER intensity across each sub-region within the area to achieve consistent curing.

[0226] FIG. 10 illustrates an example embodiment of an apparatus for translating the projection from an ER projector for randomizing emission. The embodiment of FIG. 10 further comprises a glass positioned within a cylinder. In an embodiment, the cylinder is positioned between the

[0227] #14469326vl projector and the projection target such that ER emitted from the projector passes through the glass before it triggers polymerization within the 3D printer. In an embodiment, the apparatus illustrated in FIG. 10 further comprises a friction wheel contacting the cylinder. In an embodiment, the friction wheel further comprises a rotational actuator such that when the friction wheel is rotated by the actuator, the cylinder is rotated due to friction between the wheel and the cylinder. In an embodiment, any suitable means for spinning the transparent article can be used. Non-limiting examples of suitable means for spinning the transparent article include gears, rotational actuators, belts, and the like. When the ER from the projector passes through the spinning glass, the spinning glass distributes the intensity more evenly over the projection area of the projector. In an embodiment, the speed of the rotational actuator varies throughout a projection process. Varying the speed of rotation increases the randomness of the distribution of the intensity.

[0228] FIG. 11 illustrates a cross section of the apparatus from FIG. 10. In an embodiment, the glass is tilted at an angle relative to the orthogonality of the projector. In an embodiment, the glass is tilted by 0.5 degrees, more preferably 1 degree, more preferably 1.5 degrees, more preferably 2 degrees, more preferably 2.5 degrees. FIG. 12 illustrates how a tilt relative to a ray of light causes the light to move. When a spinning glass is positioned between the projector and the projection target, tilting the spinning glass increases the radius of the area over which the projection an individual ray of ER will cover. In an embodiment, the radius of rotation caused by the tilt is at least as thick as a polymer chain to be solidified by the ER. This radius of rotation ensures distribution of the center of the pixels over the entire thickness of the polymer chain. Tilting the glass while spinning it causes the individual rays from the pixels to more effectively overlap one another, which increases the overall randomness of the distribution of the ER intensity. In an embodiment, the systems, devices, and methods described herein sacrifice resolution of the projection for randomness and even distribution. Typical uses of tilted glass include the separation of pixels, for example, to create 4k projection from 1080p. These methods increase resolution, but they also increase the variance in the distribution of the ER from the projector. In contrast, the systems, devices, and methods described herein make use of tilting glass and Snell’s law to decrease the resolution and amount of contrast between individual pixels. I n an embodiment, the systems, devices, and methods described herein tilt the lens while the projector is actively emitting ER. In an embodiment, the rotation and / or tilt of the glass is independent of the DMD. Ensuring that the rotation / tilt is not synchronized with the turning on / off of the micromirrors increases the overall randomness of the distribution of ER intensity.

[0229] #14469326vl FIG. 13A illustrates how rays from a pixel would pass through resin and into a product where there was no change in the index of refraction between the product and the resin. FIG. 13B illustrates how rays from a pixel pass through the waveguide effect when there is a change in the index of refraction between the product and the resin. FIG. 13C illustrates how translating the center ray from the pixel across the area of the product can overcome the issues caused by the waveguide effect. FIG. 13D illustrates, in accordance with certain embodiments, an angled pull waveguide effect.

[0230] FIGS. 14A-14C illustrate various types of pixel projections. FIG. 14A illustrates a projection without any embodiments of the present disclosure. In FIG. 14A, the corners of the pixels have lower intensity than the center, and the pixel lines receive no energy. FIG. 14B illustrates a projection making use of an XPR device. XPR causes the pixels to converge into smaller pixels. As such, pixel lines are still present. XPR also ensures that every part of the projection area receives some intensity of ER. The darkest spots (on the comers of each pixel) receive 50% of the energy intensity as the brightest spots. FIG. 14C illustrates a projection making use of the apparatus shown in FIG. 10. FIG. 14C is less crisp than FIG. 14B, but the darkest spots in FIG. 14C receive 68% of the energy intensity as the brightest spots. In the apparatus used to create the projection in FIG. 14C, the glass spun and tilted such that the radius of the translation of the projection was approximately 43 microns. This is very similar to the pixel size achieved by the projection (50 microns x 50 microns). FIG. 14D illustrates a projection making use of the apparatus shown in FIG. 10 wherein the radius of wobbling was approximately 75 microns, or 1.5 times the size of the pixels. In FIG. 14D, the darkest spots receive approximately 73% of the intensity as the brightest spots. FIG. 14E illustrates a projection making use of the apparatus shown in FIG. 10 wherein the radius of wobbling was approximately 100 microns, or 2 times the size of the pixels. In FIG. 14E, the darkest spots receive approximately 78% of the intensity as the brightest spots.

[0231] In an embodiment, a rotational actuator spins a cylinder containing a glass, which causes the translation of pixels reflecting from the DMD’s in the projector below the apparatus. The embodiment makes use of gears affixed to the rotational actuator and the cylinder to control the speed of rotation of the glass. In an embodiment, glass is affixed within the cylinder at an angle relative to the rays of the ER source to distribute the ER reflecting of the DMD’s more effectively throughout the projection area of the projector.

[0232] In an embodiment, a rotational actuator spins a cylinder containing a glass, which causes the translation of pixels reflecting from the DMD’s in the projector below the apparatus. The embodiment makes use of friction wheels affixed to the rotational actuator and the cylinder to

[0233] #14469326vl control the speed of rotation of the glass. In an embodiment, glass is affixed within the cylinder at an angle relative to the rays of the ER source to distribute the ER reflecting of the DMD’s more effectively throughout the projection area of the projector.

[0234] FIG. 15 illustrates an example embodiment of an apparatus making use of multiple motors for translating the spinning glass. The embodiment illustrated in FIG. 15 makes use of four motors positioned equidistant from on another wherein each of the motors are affixed to a linear actuator and each linear actuator is affixed to an article containing a glass. In an embodiment, each of the linear actuators translates a portion of the article holding the glass vertically, which dynamically changes the angle of the glass relative to the ER source. The combination of the positions of the glass relative to the ER source creates an effect that allows for more effective distribution of ER throughout the projection area of the ER source. The use of multiple motors for translation increases the amount of dynamic variation that can occur throughout an example additive manufacturing process. In an example, the multiple motors create an epitrochoid pattern of ER wherein a given position of the ER distribution overlaps minimally with previous positions over the course of an example additive manufacturing process. This minimizes the hot spot effect that can arise from a less complex pattern of ER distribution, which can facilitate the creation of a more homogenous polymer network due to the most effective distribution of ER from the source.

[0235] FIG. 16 illustrates the embodiment of the present disclosure from FIG. 15 further comprising a Z-arm that is angled by 2 degrees relative to the rays of ER from the ER source. In an embodiment, the combination of complex patterns of angling the glass relative to the ER source and angling the Z-arm more effectively overcomes potential “hot spot” problems by further distributing the ER from the source across the additively manufactured part as it forms.

[0236] While several embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and / or structures for performing the functions and / or obtaining the results and / or one or more of the advantages described herein, and each of such variations and / or modifications is deemed to be within the scope of the present disclosure. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and / or configurations will depend upon the specific application or applications for which the teachings of the present disclosure is / are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the disclose technology described herein. It is, therefore, to be understood that the foregoing embodiments are presented

[0237] #14469326vl by way of example only and that, within the scope of the appended claims and equivalents thereto, the technology of the present disclosure may be practiced otherwise than as specifically described and claimed. The present disclosure is directed to each individual feature, system, article, material, and / or method described herein. In addition, any combination of two or more such features, systems, articles, materials, and / or methods, if such features, systems, articles, materials, and / or methods are not mutually inconsistent, is included within the scope of the present disclosure.

[0238] The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.”

[0239] The phrase “and / or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Other elements may optionally be present other than the elements specifically identified by the “and / or” clause, whether related or unrelated to those elements specifically identified unless clearly indicated to the contrary. Thus, as a non-limiting example, a reference to “A and / or B,” when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A without B (optionally including elements other than B); in another embodiment, to B without A (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

[0240] As used herein in the specification and in the claims, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when separating items in a list, “or” or “and / or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of’ or “exactly one of,” or, when used in the claims, “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e. “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.” “Consisting essentially of,” when used in the claims, shall have its ordinary meaning as used in the field of patent law.

[0241] As used herein in the specification and in the claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements

[0242] #14469326vl and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and / or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

[0243] As used herein, “wt%” is an abbreviation of weight percentage. As used herein, “at%” is an abbreviation of atomic percentage.

[0244] Some embodiments may be embodied as a method, of which various examples have been described. The acts performed as part of the methods may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include different (e.g., more or less) acts than those that are described, and / or that may involve performing some acts simultaneously, even though the acts are shown as being performed sequentially in the embodiments specifically described above.

[0245] Use of ordinal terms such as “first,” “second,” “third,” etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements.

[0246] In the claims, as well as in the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of’ and “consisting essentially of’ shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.

[0247] #14469326vl

Claims

CLAIMSWhat is claimed is:

1. A system, comprising: a source of electromagnetic radiation comprising an electromagnetic radiation pattern; a support configured to support a precursor of a photochemical reaction; an optical path between the source and the precursor, when present; and a homogenizer of the electromagnetic radiation pattern, positioned in association with the optical path, configured to at least partially homogenize the electromagnetic radiation pattern.

2. The system of claim 1, wherein the homogenizer is an article movable between at least two positions, and movement between the at least two positions at least partially homogenizes the electromagnetic radiation pattern.

3. The system of any one of claims 1-2, wherein the homogenizer is angularly displaceable relative to an optical axis of the electromagnetic radiation pattern incident to the homogenizer, and is configured to at least partially homogenize the electromagnetic radiation pattern when undergoing angular displacement.

4. The system of any one of claims 1-3, wherein the homogenizer is at least partially transparent to the electromagnetic radiation and / or at least partially reflective of the electromagnetic radiation.

5. The system of claim 4, wherein the homogenizer is at least partially transparent to the electromagnetic radiation, and is configured to at least partially homogenize the electromagnetic radiation pattern when the electromagnetic radiation pattern passes through at least a portion of the homogenizer when undergoing angular displacement.

6. The system of any one of claims 4-5, wherein the homogenizer comprises glass.#14469326vl7. The system of claim 4, wherein the homogenizer is at least partially reflective of the electromagnetic radiation, and is configured to at least partially homogenize the electromagnetic radiation pattern when the electromagnetic radiation pattern is reflected by at least a portion of the homogenizer when undergoing angular displacement.

8. The system of claims 4 or 7, wherein the homogenizer comprises a metal.

9. The system of any one of claims 1-8, wherein the system is an additive manufacturing device.

10. The system of any one of claims 1-9, wherein the system is a 3D printer.

11. The system of any one of claims 1-9, wherein the source is associated with a projection device configured to blur the electromagnetic radiation.

12. The system of any of one of claims 1-11, wherein the support contains the precursor of the photochemical reaction.

13. The system of any of one of claims 1-12, wherein the support is configured to support a photopolymerizable resin.

14. The system of claim 13, wherein the support contains the photopolymerizable resin.

15. The system of any one of claims 1-14, wherein the support is configured to support a 3D printing precursor.

16. The system of claim 15, wherein the support contains the 3D printing precursor.#14469326vl17. The system of any one of claims 1-16, further comprising a spatial light modulator positioned along the optical path, the spatial light modulator configured to transmit and / or reflect the electromagnetic radiation from the source to the support.

18. The system of claim 17, wherein the spatial light modulator comprises a digital micromirror device.

19. The system of any one of claims 17-18, wherein the homogenizer is positioned between the spatial light modulator and the support.

20. The system of any one of claims 17-19, further comprising a collimator positioned along the optical path.

21. The system of claim 20, wherein the collimator is positioned between the spatial light modulator and the homogenizer.

22. The system of any one of claims 3-21, wherein the homogenizer is rotatable relative to the optical axis of the electromagnetic radiation pattern incident to the homogenizer.

23. The system of any one of claims 3-22, wherein the homogenizer is tiltable relative to the optical axis of the electromagnetic radiation pattern incident to the homogenizer.

24. The system of any one of claims 3-23, wherein the homogenizer is further linearly displaceable relative to the optical axis of the electromagnetic radiation pattern incident to the homogenizer.

25. The system of any one of claims 1-24, further comprising a motor configured to control an angular and / or linear displacement of the transparent article.#14469326vl26. The system of any one of claims 1-24, further comprising an actuator configured to control an angular and / or linear displacement of the transparent article.

27. The system of claim 1, wherein the homogenizer is configured to at least partially diffuse the electromagnetic radiation pattern.

28. The system of claim 27, wherein the homogenizer is positioned in association with the support.

29. The system of any one of claims 1-28, wherein the homogenizer comprises a fluid layer.

30. The system of claim 29, wherein the fluid layer comprises an oil.

31. The system of any one of claims 29-30, wherein the fluid layer comprises a plurality of particles dispersed in the fluid layer.

32. A method, comprising: at least partially homogenizing an electromagnetic radiation pattern to produce an at least partially homogenized electromagnetic radiation pattern; directing the at least partially homogenized electromagnetic radiation pattern at a precursor of a photochemical reaction; and carrying out a photochemical reaction initiated at least in part by the at least partially homogenized electromagnetic pattern.

33. The method of claim 32, further comprising emitting electromagnetic radiation from a source, the electromagnetic radiation comprising the electromagnetic radiation pattern.

34. The method of any one of claims 32-33, further comprising manufacturing a product from the photochemical reaction.#14469326vl35. The method of claim 34, wherein the product is an optical lens.

36. The method of any one of claims 32-35, wherein at least partially homogenizing the electromagnetic radiation pattern is performed with a homogenizer.

37. The method of claim 36, further comprising angularly displacing the homogenizer relative to an optical axis of the electromagnetic radiation pattern incident to the homogenizer to produce the at least partially homogenized electromagnetic radiation pattern.

38. The method of claim 37, wherein angularly displacing the homogenizer comprises rotating the homogenizer relative to the optical axis of the electromagnetic radiation pattern incident to the homogenizer.

39. The method of claim 38, wherein rotating the homogenizer comprises rotating the homogenizer at a speed greater than or equal to 100 revolutions per minute and less than or equal to 2,000 revolutions per minute relative to the optical axis of the electromagnetic radiation pattern incident to the homogenizer.

40. The method of any one of claims 38-39, wherein rotating the homogenizer comprises rotating the homogenizer at a speed greater than or equal to 700 revolutions per minute and less than or equal to 1,800 revolutions per minute relative to the optical axis of the electromagnetic radiation pattern incident to the homogenizer.

41. The method of any one of claims 38-40, wherein angularly displacing the homogenizer comprises titling the homogenizer relative to the optical axis of the electromagnetic radiation pattern incident to the homogenizer.

42. The method of claim 41, wherein tilting the homogenizer comprises tilting the homogenizer at an angle greater than or equal to 1 ° and less than or equal to 10 ° relative to the optical axis of the electromagnetic radiation pattern incident to the homogenizer.#14469326vl43. The method of any one of claims 41-42, wherein tilting the homogenizer comprising tilting the homogenizer at an angle greater than or equal to 2 ° and less than or equal to 5 ° relative to the optical axis of the electromagnetic radiation pattern incident to the homogenizer.

44. The method of any one of claims 37-43, wherein the homogenizer is at least partially transparent to the electromagnetic radiation and / or at least partially reflective of the electromagnetic radiation.

45. The method of claim 44, wherein the homogenizer is at least partially transparent to the electromagnetic radiation, and wherein at least partially homogenizing the electromagnetic radiation pattern comprises passing the electromagnetic radiation pattern through at least a portion of the homogenizer while angularly displacing the homogenizer.

46. The method of claim 44, wherein the homogenizer is at least partially reflective of the electromagnetic radiation, and wherein at least partially homogenizing the electromagnetic radiation pattern comprises reflecting the electromagnetic radiation pattern off at least a portion of the homogenizer while angularly displacing the homogenizer.

47. The method of any one of claims 32-35, wherein at least partially homogenizing the electromagnetic radiation pattern is performed by a component controlled via a processor executing instructions to produce the at least partially homogenized electromagnetic radiation pattern.

48. The method of claim 47, wherein the component lacks a dedicated homogenizing functionality.

49. A 3D printing system, the system comprising: a source of electromagnetic radiation; an optical path between the source and a projection target;#14469326vla pixel generator positioned in association with the optical path, operable to generate pixelated output from respective source emissions; and a pixel shifter operable to shift respective pixelated outputs into a plurality of projection pixels; the system capable of a first mode of operation, the first mode configured to shift the pixelated output into the plurality of projection pixels having high-contrast and pixel lines between adjacent projection pixels; and having a second mode of operation, the second mode configured to shift the respective pixelated output into the plurality of projection pixels, and further configured to, at least partially, homogenize the electromagnetic radiation pattern of a projection relative to the first mode of operation.

50. The system of any preceding claim, wherein the pixel shifter is configured to shift the respective source emissions into the plurality of projection pixels having high- contrast and pixel lines between adjacent projection pixels based on synchronized operation between movement of the pixel shifter and operation of the pixel generator.

51. The system of any preceding claim, wherein synchronized operation includes timing emission to occur when the pixel generator is in an on position and the pixel shifter has reached a stop position.

52. The system of any preceding claim, wherein the pixel shifter includes at least a transparent plate positioned in association with the optical path, configured to divert emissions from the pixel generator into a high contrast projection including the pixel lines between adjacent pixels.

53. The system of any preceding claim, wherein the system is further configured to, at least partially, homogenize the electromagnetic radiation pattern by increasing uniformity of intensity of the projection pixels relative to the first mode of operation.#14469326vl54. The system of any preceding claim, wherein the pixel generator is at least one of a digital micromirror device or LCD having operable sub-elements configurable between on and off positions.

55. The system of any preceding claim, wherein the system is further configured to, at least partially, homogenize the electromagnetic radiation pattern based on timing projection to occur during, at least in part, movement of the pixel shifter.

56. The system of any preceding claim, wherein the system is further configured to, at least partially, homogenize the electromagnetic radiation pattern based on a timing of operation of the pixel generator and the pixel shifter that results in at least partially overlapping shifts or a reduction in an intensity gradient.

57. The system of any proceeding claim, wherein the system is further configured to, at least partially, homogenize the electromagnetic radiation pattern based on at least one of a speed of shift, wave form and function of the shift (e.g., square, sine, etc.) magnitude of shift, duty cycle, refresh rate, positioning of pixel generator elements, timing of pixel generator and pixel shifter operation, focal length, or focal position for the projection.

58. The system of any proceeding claim, further configured to reduce pixel lines in the projection relative to the first mode of operation.

59. The system of any proceeding claim, wherein the system includes, at least, a telecentric lens in the optical path, and the shift of the respective source emissions includes a deviation in emission ray angle.

60. The system of any proceeding claim, wherein the system is further configured to, at least partially, homogenize the electromagnetic radiation pattern based on adjustments to focusing elements (e.g., lenses, prism, etc.) that offset a focal plane of the projection from the projection target.#14469326vl61. The system of any proceeding claim, wherein the projection target includes a precursor of a photochemical reaction.

62. A computer implemented method for 3D printing, the method comprising: controlling, by at least one processor, a source of electromagnetic radiation; transforming, by a pixel generator, the electromagnetic radiation into a pixelated output from respective source emissions; shifting, by a pixel shifter, respective pixelated outputs into a plurality of projection pixels; and triggering, by the at least one processor, a second mode of operation, the second mode configured to shift the respective pixelated output into the plurality of projection pixels, the triggering including an act of homogenizing, at least partially, an electromagnetic radiation pattern of a projection relative to a first mode of operation, wherein the first mode of operation is configured to shift the pixelated output into the plurality of projection pixels having high-contrast and pixel lines between adjacent projection pixels.

63. The method of any preceding claim, shifting, by the pixel shifter, respective pixelated outputs into a plurality of projection pixels, includes shifting the respective source emissions into the plurality of projection pixels having high-contrast and pixel lines between adjacent projection pixels based on synchronized operation between movement of the pixel shifter and operation of the pixel generator.

64. The method of any preceding claim, wherein the method comprises synchronizing operation to include timing emission to occur when the pixel generator is in an on position and the pixel shifter has reached a stop position.

65. The method of any preceding claim, wherein the method comprises positioning the pixel shifter in association with the optical path, and diverting emissions from the pixel generator into a high contrast projection including the pixel lines between adjacent pixels based on respective positions.#14469326vl66. The method of any preceding claim, wherein the method comprises homogenizing, at least partially, the electromagnetic radiation pattern by increasing uniformity of intensity of the projection pixels relative to the first mode of operation.

67. The method of any preceding claim, wherein the pixel generator is at least one of a digital micromirror device or LCD having operable sub-elements configurable between on and off positions.

68. The method of any preceding claim, wherein the method comprises homogenizing, at least partially, the electromagnetic radiation pattern based on timing projection to occur during, at least in part, movement of the pixel shifter.

69. The method of any preceding claim, wherein the method comprises homogenizing, at least partially, the electromagnetic radiation pattern based on a timing of operation of the pixel generator and the pixel shifter that results in at least partially overlapping shifts or a reduction in an intensity gradient.

70. The method of any preceding claim, wherein the method comprises homogenizing, at least partially, the electromagnetic radiation pattern based on at least one of a speed of shift, wave form and function of the shift (e.g., square, sine, etc.) magnitude of shift, duty cycle, refresh rate, positioning of pixel generator elements, timing of pixel generator and pixel shifter operation, focal length, or focal position for the projection.

71. The method of any preceding claim, the method comprising reducing pixel lines in the projection relative to the first mode of operation.

72. The method of any preceding claim, wherein the method comprising shifting the respective source emissions to include a deviation in emission ray angle using a telecentric lens in the optical path.#14469326vl73. The method of any preceding claim, wherein the method comprises homogenizing, at least partially, the electromagnetic radiation pattern based on adjusting focusing elements (e.g., lenses, prism, etc.) to offset a focal plane of the projection from the projection target.

74. The method of any preceding claim, wherein the projection target includes a precursor of a photochemical reaction.

75. An article made by 3D printing, comprising at least two non-parallel lines within the article, wherein a change in refractive index, density, and / or modulus along a distance of at least 1 mm of each of the at least two non-parallel lines differs from a change in refractive index and / or density along at least 1 mm of the other line by at least 5%.

76. The article of claim 75, wherein the change in refractive index, density, and / or modulus along the distance of at least 1 mm of each of the at least two non-parallel lines differs from the change in refractive index, density, and / or modulus along at least 1 mm of the other line by at least 10% or at least 20%.

77. The article of any one of claims 75-76, wherein the distance is least 2 mm, at least 5 mm, at least 10 mm, or at least 50 mm.

78. The article of any one of claims 75-77, wherein the at least two non-parallel lines are offset by at least 1 degree.

79. The article of any one of claims 75-78, wherein the at least two non-parallel lines are offset by at least 5 degrees, at least 10 degrees, or at least 15 degrees.

80. The article of any one of claims 75-79, wherein the at least two non-parallel lines are substantially perpendicular.#14469326vl81. An article made by 3D printing, comprising no line within the article which, along a distance of at least 1 mm, is there a change in refractive index, density, and / or modulus of more than 1%.

82. The article of claim 81, wherein the article comprises no line within the article which, along the distance of at least 1 mm, is the change in refractive index, density, and / or modulus more than 0.05%, more than 0.001%, more than 0.0005%, or more than 0.0001%.

83. The article of any one of claims 81-82, wherein the distance is least 2 mm, at least 5 mm, at least 10 mm, or at least 50 mm.

84. An article manufactured by the method of any of claims 1-74.#14469326vl

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