CN117048049A

CN117048049A - Photo-curing type 3D printing equipment and imaging system thereof

Info

Publication number: CN117048049A
Application number: CN202210493371.2A
Authority: CN
Inventors: 侯锋; 戴湘岳; 姜新
Original assignee: PRISMLAB CHINA Ltd
Current assignee: PRISMLAB CHINA Ltd
Priority date: 2022-05-07
Filing date: 2022-05-07
Publication date: 2023-11-14

Abstract

The invention provides an imaging system of a photo-curing type 3D printing device, which comprises a light source, an imaging element, a relay lens, a fly-eye lens array and a controller which are sequentially arranged, wherein the light source is used for emitting a light beam; the imaging element includes a pixel element array having a plurality of pixel elements through which the light beam passes to generate a light beam image; the relay lens is positioned on the output light path of the light beam image, and is used for amplifying the light beam image and outputting a first image from the light emitting side; the fly-eye lens array is arranged between the relay lens and the photosensitive material surface of the 3D printing equipment, the fly-eye lens array comprises a plurality of focusing lenses, the focusing lenses are in one-to-one correspondence with the pixel elements, and the fly-eye lens array is used for receiving the first image and outputting a second image to the photosensitive material surface; the controller is used for controlling the light source to expose, and each exposure generates the light beam image once.

Description

Photo-curing type 3D printing equipment and imaging system thereof

Technical Field

The present invention relates to a photo-curing type 3D printing apparatus, and more particularly, to an image forming system of the photo-curing type 3D printing apparatus.

Background

The 3D printing technology is to stack and bond special materials such as metal powder, ceramic powder, plastic, cell tissues and the like layer by using a computer three-dimensional design model as a blue book, and using a software layered discrete and numerical control forming system in a laser beam, a hot melting nozzle and the like mode, and finally, to stack and form a solid product. Different from the traditional manufacturing industry that the raw materials are shaped and cut in a mechanical processing mode such as a die, a turning milling mode and the like to finally produce a finished product, the three-dimensional entity is changed into a plurality of two-dimensional planes through 3D printing, and the manufacturing complexity is greatly reduced through material processing and layer-by-layer stacking production. The digital manufacturing mode can directly generate parts with any shape from the computer graphic data without complex process, huge machine tool and numerous manpower, so that the production and manufacturing can be extended to a wider production crowd range.

At present, the forming mode of the 3D printing technology is continuously evolving, and the used materials are also various. Among the various molding methods, the photo-curing method is a more mature method. The photocuring method is to utilize the principle that the photosensitive resin is cured after being irradiated by ultraviolet laser to carry out material accumulation molding, and has the characteristics of high molding precision, good surface smoothness, high material utilization rate and the like.

Fig. 1 shows a basic structure of a photo-curing type 3D printing apparatus. The 3D printing apparatus 100 includes a material tank 110 for accommodating photosensitive resin, an imaging system 120 for curing the photosensitive resin, and a lift 130 for connecting a molded workpiece. The imaging system 120 is positioned above the chute 110 and is configured to illuminate the beam image to cure a layer of photosensitive resin on the surface of the chute 110. After each time the imaging system 120 irradiates the light beam image to cure one layer of photosensitive resin, the lifting table 130 drives the molded layer of photosensitive resin to slightly descend, and the cured top surface of the workpiece uniformly spreads the photosensitive resin through the scraping plate 131 to wait for the next irradiation. And by means of the circulation, the three-dimensional workpiece formed in a layer-by-layer accumulated mode can be obtained.

With the wide application of 3D printing technology, in some cases, the volume of the three-dimensional workpiece is large, and printing with a large format is required. However, if the printing accuracy and the definition of the molded work are ensured while the width is enlarged, the current printing apparatus is difficult to achieve and the implementation cost is high.

Disclosure of Invention

The invention aims to provide a photo-curing type 3D printing device and an imaging system thereof, wherein a large-format and high-precision printed image can be obtained at low cost.

The application provides an imaging system of a photo-curing type 3D printing device, which comprises a light source, an imaging element, a relay lens, a fly-eye lens array and a controller which are sequentially arranged, wherein the light source is used for emitting a light beam; the imaging element includes a pixel element array having a plurality of pixel elements through which the light beam passes to generate a light beam image; the relay lens is positioned on the output light path of the light beam image, and is used for amplifying the light beam image and outputting a first image from the light emitting side; the fly-eye lens array is arranged between the relay lens and the photosensitive material surface of the 3D printing equipment, the fly-eye lens array comprises a plurality of focusing lenses, the focusing lenses are in one-to-one correspondence with the pixel elements, and the fly-eye lens array is used for receiving the first image and outputting a second image to the photosensitive material surface; the controller is used for controlling the light source to expose, and each exposure generates the light beam image once.

In an embodiment of the application, the beam image comprises a sub-beam image corresponding to each pixel element, the first image comprises a first sub-image corresponding to each sub-beam image, the second image comprises a second sub-image corresponding to each first sub-image, each first sub-image has a first energy distribution width, each second sub-image has a second energy distribution width, and the second energy distribution width is narrower than the first energy distribution width.

In an embodiment of the present application, the optical system further includes a projection lens, the projection lens is disposed between the fly eye lens array and the photosensitive material surface, and the projection lens is configured to magnify the second image and output a third image to the photosensitive material surface.

In an embodiment of the application, the third image comprises a third sub-image corresponding to each of the second sub-images, each of the third sub-images having a third energy distribution width, the third energy distribution width being wider than the second energy distribution width.

In an embodiment of the application, the controller is further configured to control the imaging element, the relay lens and the fly-eye lens array to move together at each exposure to project the second image corresponding to each exposure to a different position on the surface of the photosensitive material.

In an embodiment of the present application, the second sub-images corresponding to each exposure do not overlap each other on the surface of the photosensitive material.

In an embodiment of the present application, the second sub-image corresponding to each exposure is covered on the surface of the photosensitive material.

In an embodiment of the application, the controller is further configured to control the imaging element, the relay lens and the fly-eye lens array to move together at each exposure to project the third image corresponding to each exposure to a different position on the surface of the photosensitive material.

In an embodiment of the present application, the third sub-images corresponding to each exposure do not overlap each other on the surface of the photosensitive material.

In an embodiment of the present application, the third sub-image corresponding to each exposure is covered on the surface of the photosensitive material.

In one embodiment of the application, the imaging element comprises a transmissive imaging element.

In one embodiment of the application, the imaging element comprises a reflective imaging element.

In one embodiment of the application, the beam images of each exposure contain the same image information.

In one embodiment of the application, each exposure beam image contains different image information.

The application also provides a light-curing type 3D printing device for solving the technical problems, which comprises the imaging system.

The imaging system of the photo-curing type 3D printing equipment adopts the relay lens with the amplifying function and the fly-eye lens array with the focusing function to be matched, so that a beam image generated by an imaging element is focused into a second image with narrower energy distribution width, and the resolution of the image is ensured while the printing breadth is amplified at lower cost; by moving the imaging element, the relay lens and the fly's eye lens array and exposing for multiple times, the gaps between the projection patterns can be filled, further improving the resolution and definition of the image.

Drawings

In order to make the above objects, features and advantages of the present application more comprehensible, embodiments accompanied with figures are described in detail below, wherein:

fig. 1 is a basic structural schematic diagram of a photo-curing type 3D printing apparatus;

fig. 2 is a schematic view of a part of the structure of a photo-curing type 3D printing apparatus;

FIG. 3 is a schematic illustration of a projected image formed on a photosensitive material surface 240 according to the 3D printing apparatus shown in FIG. 2;

fig. 4 is a schematic view showing a partial structure of an image forming system of a photo-curing type 3D printing apparatus according to an embodiment of the present application;

fig. 5 is a schematic view of energy distribution of a first sub-image and a second sub-image of an imaging system of a photo-curing type 3D printing device according to an embodiment of the present application;

FIG. 6 is a schematic diagram of a projected image formed on a surface of a photosensitive material by multiple movements of an imaging system of a photo-curing type 3D printing apparatus according to an embodiment of the present application;

FIG. 7 is a schematic diagram of a projected image formed on a surface of a photosensitive material by multiple movements of an imaging system of a photo-curing type 3D printing apparatus according to an embodiment of the present application;

fig. 8 is a partial schematic view of an image forming system of a photo-curing type 3D printing apparatus according to another embodiment of the present application;

Fig. 9 is a schematic view of an optical path range of an imaging system of a photo-curing type 3D printing apparatus according to an embodiment of the present application;

fig. 10 is a partial schematic view of an image forming system of a photo-curing type 3D printing apparatus according to another embodiment of the present application;

fig. 11 is a side view of the perspective view of fig. 10.

Detailed Description

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are used in the description of the embodiments will be briefly described below. It is apparent that the drawings in the following description are only some examples or embodiments of the present application, and it is apparent to those of ordinary skill in the art that the present application may be applied to other similar situations according to the drawings without inventive effort. Unless otherwise apparent from the context of the language or otherwise specified, like reference numerals in the figures refer to like structures or operations.

As used in the specification and in the claims, the terms "a," "an," "the," and/or "the" are not specific to a singular, but may include a plurality, unless the context clearly dictates otherwise. In general, the terms "comprises" and "comprising" merely indicate that the steps and elements are explicitly identified, and they do not constitute an exclusive list, as other steps or elements may be included in a method or apparatus.

The relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present application unless it is specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective parts shown in the drawings are not drawn in actual scale for convenience of description. Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but should be considered part of the specification where appropriate. In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.

In the description of the present application, it should be understood that the azimuth or positional relationships indicated by the azimuth terms such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal", and "top, bottom", etc., are generally based on the azimuth or positional relationships shown in the drawings, merely to facilitate description of the present application and simplify the description, and these azimuth terms do not indicate and imply that the apparatus or elements referred to must have a specific azimuth or be constructed and operated in a specific azimuth, and thus should not be construed as limiting the scope of protection of the present application; the orientation word "inner and outer" refers to inner and outer relative to the contour of the respective component itself.

Spatially relative terms, such as "above … …," "above … …," "upper surface at … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial location relative to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "above" or "over" other devices or structures would then be oriented "below" or "beneath" the other devices or structures. Thus, the exemplary term "above … …" may include both orientations of "above … …" and "below … …". The device may also be positioned in other different ways (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

The embodiment of the application describes a light-curing type 3D printing device and an imaging system thereof, wherein the imaging system adopts a relay lens with an amplifying function and a fly-eye lens array with a focusing function to match, so that a light beam image is focused into a second image with a narrower energy distribution width, and the resolution of the image is ensured while the light beam image is amplified; by moving the imaging element, the relay lens and the fly's eye lens array and exposing for multiple times, the gaps between the projection patterns can be filled, further improving the resolution and definition of the image.

Fig. 2 is a schematic view of a part of the structure of a photo-curing type 3D printing apparatus. Fig. 2 mainly shows an image forming-related structure in the 3D printing apparatus. As shown in fig. 2, the partial structure includes a light source 210, an imaging element 220, a projection lens 230, and a photosensitive material surface 240. Some 3D printing devices include a partial structure as shown in fig. 2, in which a light source 210 emits a light beam through an imaging element 220 to form an image to be printed, and a projection lens 230 is used to magnify the image, thereby forming a magnified image on a photosensitive material surface 240. As shown in fig. 2, the imaging element 220 is composed of a plurality of pixel elements 221, and an image to be printed is formed after a light beam passes through each pixel element 221.

Fig. 3 is a schematic view of a projected image formed on a photosensitive material surface 240 according to the 3D printing apparatus shown in fig. 2. The beam of light is amplified after passing through the individual pixel elements 221 to form individual spots 310 on the photosensitive material surface 240, the size of the shaped voxels obtained by the spot 310 irradiating the photosensitive material for curing is also amplified, and a plurality of shaped voxels form a printed workpiece. For adjacent pixel elements 221, the gaps 320 between adjacent spots 310 are also scaled up, which can result in uneven surface and large granularity of the molded workpiece. Thus, the accuracy and resolution of printing is sacrificed while the print swath is enlarged in this manner.

Fig. 4 is a schematic view of a part of the structure of an image forming system of a photo-curing type 3D printing apparatus according to an embodiment of the present application. Referring to fig. 4, the imaging system of this embodiment includes a light source 410, an imaging element 420, a relay lens 430, a fly-eye lens array 440, and a controller, which are sequentially arranged, wherein the light source 410 is used to emit a light beam; the imaging element 420 includes a pixel element array having a plurality of pixel elements through which the light beam passes to generate a light beam image; the relay lens 430 is located on an output optical path of the beam image, and is configured to amplify the beam image and output a first image from a light emitting side; the fly-eye lens array 440 is disposed between the relay lens 430 and the photosensitive material surface 460 of the 3D printing apparatus, the fly-eye lens array 440 includes a plurality of focusing lenses, the focusing lenses are in one-to-one correspondence with the pixel elements, and the fly-eye lens array 440 is configured to receive the first image and output the second image to the photosensitive material surface 460; the controller is configured to control the light source 410 to perform an exposure, each exposure generating a beam image.

Fig. 4 shows an example, and is not intended to limit the actual positional relationship between the respective elements. In some embodiments, the light source 410 and the imaging element 420 may be integrally provided or may be separately provided as shown in fig. 4. In some embodiments, the light source 410 may be disposed at a side of the imaging element 420.

The application is not limited to the specific embodiment of imaging element 420. The imaging element 420 may include a transmissive imaging element and a reflective imaging element, by type. Imaging element 420 may include liquid crystal technology (LCD), light shaping technology or digital light processing (Digital Light Procession, DLP) projection technology, liquid crystal on silicon (Liquid Crystal on Silicon, LCOS) projection technology, and the like, depending on the imaging technology. The transmissive imaging member includes a liquid crystal imaging member LCD. Reflective imaging elements include digital light processing projection imaging elements DLP or liquid crystal on silicon projection imaging elements LCOS.

The LCD device is a transmissive imaging element, whose main hardware is a liquid crystal panel, in which a plurality of pixels are included, each pixel can individually control the polarization direction of polarized light, and the polarization filters on both sides of the liquid crystal panel can control whether light of a certain pixel passes through, so that a light beam passing through the liquid crystal panel system is imaged.

DLP projection imaging techniques are implemented using digital micromirror elements (Digital Micromirror Device, DMD) to control the reflection of light. The digital micromirror device can be regarded as a mirror. This mirror is composed of hundreds of thousands or even millions of micromirrors. Each micromirror represents a pixel from which the image is formed. Each micromirror is independently controllable to determine whether to reflect light to the projection lens. Finally, the entire mirror reflects the desired beam image.

LCOS is a matrix liquid crystal display device based on a reflective mode with very small pixel size. The matrix is fabricated on a silicon chip using CMOS technology. The circuitry of the matrix provides a voltage between the electrode of each pixel and the common transparent electrode, separated by a thin layer of liquid crystal. The electrode of the pixel is also a mirror (hereinafter referred to as mirror electrode), and the electrodes of all the pixels together constitute a mirror surface. An electronic circuit for controlling image formation is fabricated on the silicon chip, and the polarization direction of the incident polarized light of each pixel is changed by controlling the state of the liquid crystal molecules. The light reflected by the mirror electrode is optically separated from the incident light to be magnified and imaged onto an object by the projection objective. Eventually, the entire reflection projects the desired beam image.

As shown in fig. 4, whichever of the imaging elements, the imaging element 420 includes a pixel element array having a plurality of pixel elements. For example, as shown in fig. 4, the imaging element 420 has a flat plate shape, in which pixel elements of a plurality of rows and columns are distributed to constitute a pixel element array. Each pixel element represents an imaging unit, the more pixel elements, the higher the resolution imaged. Fig. 4 is not intended to limit the shape, size, and type of imaging element 420.

As shown in fig. 4, the light source 410 emits a light beam that generates a light beam image through an array of pixel elements in the imaging element 420. It will be appreciated that for a transmissive imaging element, the beam is transmitted through the array of pixel elements to form a beam image, and for a reflective imaging element, the beam is reflected off the array of pixel elements to form a beam image. Either way, the imaging element 420 is used to generate a beam image.

As shown in fig. 4, the relay lens 430 receives the beam image from the imaging element 420 and outputs a first image. The side of the relay lens 430 facing downward of the fly-eye lens array 440 is the light-emitting side thereof. The relay lens 430 is a type of convex lens, and is disposed on the output optical path of the beam image. The present application is not limited to the position and size of relay lens 430. When the relay lens 430 is provided, it is sufficient to be able to receive the beam image entirely.

As shown in fig. 4, fly-eye lens array 440 includes a plurality of focusing lenses. In some embodiments, the focusing lens is a convex lens and the fly eye lens array 440 is comprised of a plurality of tiny convex lenses. And the number, the positions and the arrangement mode of the focusing lenses are in one-to-one correspondence with the pixel elements in the pixel element array. In the embodiment shown in fig. 4, fly-eye lens array 440 is in the shape of a flat plate like imaging element 420 having a size larger than imaging element 420, and accordingly, each focusing lens has a size larger than that of each pixel element.

In some embodiments, fly's eye lens array 440 may be pressed from a resin material.

The size of each focusing lens in the fly-eye lens array 440 of the present application is approximately in the order of cm or mm, which has the advantage of low processing cost. Without limitation, the pixel size in imaging element 420 is on the order of microns.

In the imaging system of this embodiment, the fly-eye lens array 440 plays a role of focusing, and each pixel in the first image enlarged through the relay lens 430 can be individually focused, outputting a focused second image.

As shown in fig. 4, the second image is output directly to the photosensitive material surface 460. The photosensitive material surface 460 may refer to the upper surface of the liquid photosensitive resin contained inside the material tank 110 as shown in fig. 1. In 3D printing, the light beam emitted from the light source 410 passes through the imaging element 420 to generate a light beam image, and the light beam image passes through the relay lens 430 and the fly eye lens array 440 to form a second image, and the second image irradiates the photosensitive material surface 460 to form light spots, each of which corresponds to one pixel element. According to the principle of the photo-curing type 3D printing, the photosensitive material subjected to light is cured, and the photosensitive material not subjected to light remains unchanged, whereby a layer of molded work corresponding to the second image can be obtained.

In an embodiment of the present application, the distances between the imaging element 420, the relay lens 430 and the fly-eye lens array 440 may be designed according to the actual situation to obtain a desired projection image.

In some embodiments, the distance between the photosensitive material surface 460 and the fly eye lens array 440 in FIG. 4 is very close.

In some embodiments, the photosensitive material surface 460 and the fly eye lens array 440 are not in contact with each other.

In some embodiments, photosensitive material surface 460 and fly eye lens array 440 are in contact with each other.

In some embodiments, the beam image comprises a sub-beam image corresponding to each pixel element, the first image comprises a first sub-image corresponding to each sub-beam image, the second image comprises a second sub-image corresponding to each first sub-image, each first sub-image has a first energy distribution width, each second sub-image has a second energy distribution width, and the second energy distribution width is narrower than the first energy distribution width. In these embodiments, the image generated by the light beam passing through each pixel element is referred to as a first sub-image, and therefore, the first image includes a plurality of first sub-images, and similarly, the second image includes a plurality of second sub-images, the first sub-images and the second sub-images being in one-to-one correspondence, indicating that the positions of the first sub-images in the first image and the second sub-images in the second image are corresponding, and the total number of the first sub-images and the total number of the second sub-images are the same. It should be noted that, the position of the first sub-image in the first image corresponds to the position of the second sub-image in the second image, and the position of the first sub-image and the position of the second sub-image are not limited to be identical. In some embodiments, the position of the first sub-image in the first image and the position of the second sub-image in the second image have a center-symmetrical relationship, e.g., a first sub-image in the first image located in the upper left corner corresponds to a second sub-image in the second image located in the lower right corner.

Fig. 5 is an energy distribution diagram of a first sub-image and a second sub-image of an imaging system of a photo-curing type 3D printing device according to an embodiment of the application. Referring to fig. 5, a first energy profile 510 of a first sub-image and a second energy profile 520 of a second sub-image are shown, both given by way of example as normal profiles. The present description is illustrated by way of example in fig. 5, and the specific shapes of the first energy profile 510 and the second energy profile 520 shown in fig. 5 are not intended to be limiting.

Referring to fig. 5, in the coordinate system, the horizontal axis x represents the position, and the vertical axis E represents the energy or energy density. The X-axis in fig. 5 may represent the X or Y dimension of the projection plane, assuming that the projection plane is located in an XY coordinate system. In some cases, the energy peaks of the first energy distribution curve 510 and the second energy distribution curve 520 do not necessarily correspond to the same position x, and for comparison, the peak points of the first energy distribution curve 510 and the second energy distribution curve 520 are located at an origin O at x=0 in fig. 5, where the position of the origin O represents an intersection point of the optical path center line of the first sub-image or the second sub-image and the projection plane, that is, the center with the most dense energy. The first energy distribution width W1 and the second energy distribution width W2 may be determined as needed. For example, according to the characteristics of a normal curve, it is assumed that the first energy distribution curve 510 is expected to be μ 1, the standard deviation is σ1, and the position of the peak is the expected value. If the energy distribution width is determined with 95% energy, the width of the interval [ -1.96 σ 1,1.96 σ1] is selected as the first energy distribution width W1, indicating that the area under the first energy distribution curve 510 is 95% of the total area in the interval. Similarly, assuming that the second energy distribution curve 520 is expected to be μ2 and the standard deviation is σ2, the width of the [ -1.96 σ 2,1.96 σ2] interval is selected as the second energy distribution width W2.

In some embodiments, the total area under the first energy profile 510 and the total area under the second energy profile 520 are equal. In an ideal case, the transmittance of the light beam through relay lens 430 and fly eye lens array 440 is 100%, and the total area under first energy distribution curve 510 and the total area under second energy distribution curve 520 are equal. In some embodiments, both relay lens 430 and fly-eye lens array 440 are coated with a coating that provides good light transmission.

The illustration in fig. 5 is merely an example, and in other embodiments, the individual energy distribution widths may be determined as desired. The first energy distribution width and the second energy distribution width are determined by the same method, so that the first energy distribution width and the second energy distribution width are comparable.

The second sub-image formed by focusing the first sub-image by the fly-eye lens array 440 has a second energy distribution width W2 which is obviously smaller than the first energy distribution width W1, which indicates that the energy of the second sub-image is more concentrated. For a wider energy distribution, this means that the energy distribution is dispersed, and the area above the material excitation threshold is larger, so that the forming voxels are larger and the resulting formed workpiece is not fine. On the other hand, the adjacent first sub-images have more overlapping parts of energy distribution, so that the adjacent forming voxels have parts which are repeatedly exposed when the photo-curing type 3D printing is carried out, the surface of the forming workpiece is uneven, and the time required for curing is longer because the energy distribution is relatively dispersed. The more concentrated energy distribution means that there are fewer overlapping portions of the energy distribution between adjacent second sub-images, and the corresponding photosensitive material is easier to cure due to the increased brightness of the focal point, thereby accelerating the curing speed.

In some embodiments, the controller in the imaging system of the present application is further configured to control the movement of the imaging element, relay lens, and fly-eye lens array together at each exposure to project a second image corresponding to each exposure to a different location on the surface of the photosensitive material.

Referring to fig. 4, in some embodiments, the controller includes a micro-displacement driving mechanism connected to the imaging element 420, the relay lens 430 and the fly-eye lens array 440, and capable of driving the imaging element 420, the relay lens 430 and the fly-eye lens array 440 to move arbitrarily in a horizontal plane where they are located. It should be noted that, once the imaging element 420, the relay lens 430 and the fly eye lens array 440 are disposed, the positions of the imaging element, the relay lens and the fly eye lens array are fixed, and the imaging element, the relay lens and the fly eye lens array may be physically connected to each other or may be disposed independently. For the three-way interconnection embodiment, the micro-displacement driving mechanism may be integrally connected with the three, for example, only one of them may be physically connected, and the three may be integrally driven to move together by a unified command. For the embodiment that the three are independently arranged, the micro-displacement driving mechanism can be physically connected with all the three, and the three are driven to move simultaneously through synchronous commands.

Fig. 6 is a schematic view of a projected image formed on a surface of a photosensitive material through a plurality of movements by an imaging system of a photo-curing type 3D printing apparatus according to an embodiment of the present application. Referring to fig. 6, four projection images A, B, C, D sequentially formed in order are formed on the same photosensitive material surface 601. The photosensitive material surface 601 corresponds to the photosensitive material surface 460 shown in fig. 4.

Referring to fig. 6, the projected image D is the final projected image formed on the surface 601 of the layer of photosensitive material. In order to form the projection image D, 4 exposures are required.

In some embodiments, the beam images of each exposure contain the same image information. Taking fig. 6 as an example, within the dashed-line frame in the projection image D, the four second sub-images 611, 621, 631, 641 contain the same image information.

Referring to fig. 6, at the first exposure, a projection image a is formed, which includes 16 squares, and image information to be projected is represented by the 16 squares. The projected image a is formed after focusing by fly-eye lens array 440, wherein each square corresponds to a second sub-image 611. The focused second sub-images 611 have more concentrated energy distribution, and little or no overlapping between the sequentially adjacent second sub-images 611 is shown in the projection image a, with a larger gap between each second sub-image 611.

An xy coordinate system is shown in fig. 6 to illustrate the direction and location of the plane in which the surface 601 of the photosensitive material lies. Referring to fig. 6, at the time of the second exposure, the controller drives the imaging element 420, the relay lens 430, and the fly-eye lens array 440 to move rightward together in the positive x-axis direction so that the second sub-image 621 to be generated just fills in the space of the second sub-image 611 adjacent along the x-axis. At the third exposure, the controller drives the imaging element 420, the relay lens 430, and the fly-eye lens array 440 to move downward together in the negative y-axis direction so that the second sub-image 631 to be generated fills exactly in the void of the second sub-image 621 adjacent in the y-axis. At the fourth exposure, the controller drives the imaging element 420, the relay lens 430, and the fly-eye lens array 440 together to move to the left in the x-axis negative direction so that the second sub-image 641 to be generated is just filled in the space of the adjacent first sub-image 611 in the y-axis.

As shown in fig. 6, in some embodiments, the corresponding second sub-images 611, 621, 631, 641 of each exposure do not overlap each other at the photosensitive material surface 601. In other embodiments, the corresponding second sub-images 611, 621, 631, 641 of each exposure may overlap at the photosensitive material surface 601.

After the above 4 exposures and 3 movements, the projected image D is substantially full of the photosensitive material surface 601. According to the imaging mode, the second sub-images generated by each exposure have narrower energy distribution, so that rapid imaging can be realized, gaps between adjacent second sub-images are filled by multiple exposure, the layer of formed workpiece has a flat surface, the granularity of the formed workpiece is reduced, and the printing resolution and precision are improved.

It will be appreciated that after the projected image D is formed, the controller drives the imaging element 420, relay lens 430 and fly-eye lens array 440 back to the initial positions corresponding to the projected image a in preparation for printing of the next layer of the molded workpiece.

When the photo-curing material is cured, the material has a certain amount of shrinkage, and when the large-area photo-curing material is simultaneously photosensitive cured, larger continuous internal stress can be generated, so that the cured object is warped and deformed. According to the method provided by the embodiment of the application, the second sub-images are solidified at different times, so that the influence on the pulling of the surrounding second sub-images when the second sub-images are solidified and contracted can be reduced, and the degree of warping and deformation of the solidified molded workpiece is improved.

Referring to fig. 6, each of the second sub-images 611, 621, 631, 641 is referred to as a pixel, and a plurality of pixels arranged at intervals on the photosensitive material surface 601 are exposed and cured to form a projection image a, the surrounding area of each pixel which is pulled during curing and shrinkage is also a liquid photosensitive material, and the variability of the liquid material counteracts the pulling effect and avoids the accumulation of internal stress; then, a second exposure curing is performed to form a projected image B, and the pixels (even columns) cured at this time are also liquid photosensitive materials around both the upper and lower directions, so that the variability of the liquid materials in both directions counteracts the influence of pulling; then, a third exposure curing is performed to form a projected image C, and the pixels (even rows) cured at this time are still liquid photosensitive material around the left side direction, so that the variability of the liquid material in this direction counteracts the pulling effect; finally, the fourth exposure curing is carried out to form a projection image D, and only the periphery of the cured pixels is solid photosensitive material. However, only 1/4 of the material is cured, and the characteristic of the focused pixel point is that the middle is brighter than the surrounding, so that the middle of the pixel is cured faster than the edge when the curing occurs, and the internal stress during the middle curing can be absorbed by the surrounding uncured resin to be partially absorbed, and the accumulated internal stress is very small when the curing is completed. More importantly, because only the pixel points which are mutually separated at the same time are cured, adjacent pixels cannot be cured at the same time, and mutual pulling of the pixel points during simultaneous curing is avoided.

In a preferred embodiment, referring to fig. 7, after the first exposure and curing is performed to form the projection image a, the second exposure and curing is performed to form the projection image B. The pixels cured in the projection image B and the pixels cured in the projection image A are diagonally but not adjacent to each other, so that the cured pixels are also liquid photosensitive materials in all four directions around, and the variability of the liquid materials counteracts the influence of pulling. The third exposure curing is then performed to form the projected image C and the fourth exposure curing is performed to form the projected image D in the same manner as in the embodiment shown in fig. 6, and is not developed again.

Fig. 6 and 7 are examples only, and are not intended to limit the number of exposures. When the exposure is performed for 9 times, 16 times or the like, a plurality of projection images with mutually non-adjacent pixel points can be preferentially exposed, so that the influence of mutual pulling is reduced to the greatest extent.

In some embodiments, the beam image for each exposure contains different image information. Taking fig. 6 as an example, within the dashed-line frame in the projection image D, the four second sub-images 611, 621, 631, 641 contain different image information. This means that the resolution of the projected pattern is correspondingly 4 times higher than the original. The accuracy of 3D printing is significantly improved. The different image information may be from 4 different image files that may form a complete image, or may be 4 sub-images that are extracted from an image of the same image file after processing.

Fig. 8 is a partial schematic diagram of an image forming system of a photo-curing type 3D printing apparatus according to another embodiment of the present application. The imaging system of this embodiment includes a light source 810, an imaging element 820, a relay lens 830, a fly-eye lens array 840, a projection lens 850, and a controller. The projection lens 850 is disposed between the fly eye lens array 840 and the photosensitive material surface 860, and the projection lens 850 is configured to magnify the second image and output a third image to the photosensitive material surface 860.

In comparison to the embodiment shown in fig. 4, a projection lens 850 is added to the imaging system shown in fig. 8. The foregoing descriptions of the light source 410, the imaging element 420, the relay lens 430, the fly-eye lens array 440, and the controller are all used to describe the light source 810, the imaging element 820, the relay lens 830, the fly-eye lens array 840, the projection lens 850, and the controller in the embodiment shown in fig. 8, and the same descriptions are not expanded.

It should be noted that the positional relationship between the respective elements in the embodiment shown in fig. 8 may be different from that in the embodiment shown in fig. 3. For example, fly's eye lens array 840 and projection optics 850 are positioned at a distance from each other. The projection lens 850 is spaced from the photosensitive material surface 860 by a distance that is not in contact with each other.

In the embodiment shown in fig. 8, projection lens 850 may be a convex lens for magnifying the second image from compound eye lens array 840 into a third image and projecting the magnified third image onto the photosensitive material surface.

In some embodiments, the third image includes a third sub-image corresponding to each of the second sub-images, each of the third sub-images having a third energy distribution width that is wider than the second energy distribution width, that is, the energy distribution of the projected image in its XY directions is broadened after magnification by the projection lens 850, with the peak of the third energy distribution being less than the peak of the second energy distribution. In these embodiments, the third sub-image and the second sub-image are in one-to-one correspondence. As shown in connection with fig. 5, the third energy distribution width W3 of each third sub-image is wider than the second energy distribution width W2 due to the focusing action of the convex lens.

According to the embodiment shown in fig. 8, the controller controls the imaging element 820, relay lens 830 and fly-eye lens array 840 to move together to project a third image corresponding to each exposure to a different location on the photosensitive material surface 860. In comparison with the embodiments shown in fig. 6 and 7, the embodiments replace the second image with the third image, and the related description may refer to fig. 6 and 7 and the corresponding description, and replace the second image with the third image, which is not expanded.

The third image obtained is enlarged by using the projection lens 850, and is suitable for a larger three-dimensional printing scene.

In some embodiments, projection lens 850 is a lens with a demagnification function, such as a concave lens. According to these embodiments, the energy of the third sub-image may be more concentrated than the first sub-image, so that the energy of the light spot projected onto the photosensitive material surface 860 may be more concentrated, the imaging element 820, the relay lens 830 and the fly-eye lens array 840 may be exposed more times for a layer of molded work piece, the gap between the projected images formed by the sub-images may be filled each time, only a small amount of printing time may be required to increase, and a hundred times of the resolution of the final projected image may be increased without changing the total energy, thereby obtaining higher resolution and definition of the projected image.

In some embodiments, the corresponding third sub-images of each exposure do not overlap each other at the surface of the photosensitive material.

In some embodiments, the third sub-image corresponding to each exposure is spread over the surface of the photosensitive material.

In some embodiments, when imaging element 820 is a digital light processing projection imaging element DLP or a liquid crystal on silicon projection imaging element LCOS, which may itself include projection optics 850, relay lens 830 and fly eye lens array 840 may be added to form the imaging system shown in FIG. 8.

Referring to fig. 8, the general optical path of a light beam of the present application after exiting a light source 810 through various components is shown. Fig. 9 shows the light path range of the imaging system according to the embodiment shown in fig. 8 with several lines L1, L2, L3, i.e. the light path range is limited within the lines L1, L2, L3 between the individual elements in fig. 9. Referring to fig. 8 and 9, the distance between imaging element 820, relay lens 830, fly eye lens array 840, projection optics 850, and photosensitive material surface 860 may affect the size of the third image that is ultimately projected onto photosensitive material surface 860; lens parameters of relay lens 830, fly-eye lens array 840, and projection lens 850, such as focal length, radius, etc., affect the size, energy distribution, etc., of the first, second, and third images, respectively. The spacing of the elements can be adjusted according to actual needs, and proper lens parameters are selected, so that a high-precision and high-resolution third image is obtained.

The imaging system shown in fig. 10 is the same as that shown in fig. 8, omitting the light source 801, in which the optical path of a beam image emitted from a certain pixel element is marked with a straight line. As shown in fig. 10, the pixel element P1 is located on the left side in the imaging element 820, and the beam image emitted from the pixel element P1 passes through the relay lens 830 to become a first sub-image, and is projected onto one focusing lens P2 in the fly-eye lens array 840; the first sub-image is focused by the focusing lens P2 to become a second sub-image, and projected onto the projection lens 850; the second sub-image is magnified by the projection lens 850 into a third sub-image and projected onto the photosensitive material surface 860 at P3.

Fig. 11 is a side view corresponding to the perspective view shown in fig. 10. As can be appreciated in conjunction with fig. 10 and 11, the position of the pixel element in the imaging element 820 is positively correlated with the position of the final third sub-image at the photosensitive material surface 860. For example, the pixel elements are located in the first left column third row in imaging element 820, and if photosensitive material surface 860 is to be gridded, the pixel elements are also located in the first left column third row in photosensitive material surface 860.

According to the embodiment shown in fig. 8, the third image projected onto the photosensitive material surface 860 is further magnified using the projection lens 850, and the energy dispersion problem due to the overall magnification of the projection lens 850 is compensated in advance by focusing the beam image before the projection lens 850 using the relay lens 830 and the fly-eye lens array 840 to generate a second image; and fills the gaps between adjacent projection patterns by controlling the imaging element 820, the relay lens 830 and the fly-eye lens array 840 to move together, improving the precision and resolution of the molded workpiece.

The application also includes a light curable 3D printing device comprising an imaging system as described above. According to the photo-curing type 3D printing device, a large-format and high-precision printed image can be obtained at a low cost.

While the basic concepts have been described above, it will be apparent to those skilled in the art that the foregoing disclosure is by way of example only and is not intended to be limiting. Although not explicitly described herein, various modifications, improvements and adaptations of the application may occur to one skilled in the art. Such modifications, improvements, and modifications are intended to be suggested within the present disclosure, and therefore, such modifications, improvements, and adaptations are intended to be within the spirit and scope of the exemplary embodiments of the present disclosure.

Meanwhile, the present application uses specific words to describe embodiments of the present application. Reference to "one embodiment," "an embodiment," and/or "some embodiments" means that a particular feature, structure, or characteristic is associated with at least one embodiment of the application. Thus, it should be emphasized and should be appreciated that two or more references to "an embodiment" or "one embodiment" or "an alternative embodiment" in various positions in this specification are not necessarily referring to the same embodiment. Furthermore, certain features, structures, or characteristics of one or more embodiments of the application may be combined as suitable.

Similarly, it should be noted that in order to simplify the description of the present disclosure and thereby aid in understanding one or more inventive embodiments, various features are sometimes grouped together in a single embodiment, figure, or description thereof. This method of disclosure, however, is not intended to imply that more features than are required by the subject application. Indeed, less than all of the features of a single embodiment disclosed above.

In some embodiments, numbers describing the components, number of attributes are used, it being understood that such numbers being used in the description of embodiments are modified in some examples by the modifier "about," approximately, "or" substantially. Unless otherwise indicated, "about," "approximately," or "substantially" indicate that the number allows for a 20% variation. Accordingly, in some embodiments, numerical parameters set forth in the specification and claims are approximations that may vary depending upon the desired properties sought to be obtained by the individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and employ a method for preserving the general number of digits. Although the numerical ranges and parameters set forth herein are approximations in some embodiments for use in determining the breadth of the range, in particular embodiments, the numerical values set forth herein are as precisely as possible.

While the application has been described with reference to the specific embodiments presently, it will be appreciated by those skilled in the art that the foregoing embodiments are merely illustrative of the application, and various equivalent changes and substitutions may be made without departing from the spirit of the application, and therefore, all changes and modifications to the embodiments are intended to be within the scope of the appended claims.

Claims

1. An imaging system of a photo-curing type 3D printing device comprises a light source, an imaging element, a relay lens, a fly-eye lens array and a controller which are sequentially arranged, wherein,

the light source is used for emitting a light beam;

the imaging element includes a pixel element array having a plurality of pixel elements through which the light beam passes to generate a light beam image;

the relay lens is positioned on the output light path of the light beam image, and is used for amplifying the light beam image and outputting a first image from the light emitting side;

the fly-eye lens array is arranged between the relay lens and the photosensitive material surface of the 3D printing equipment, the fly-eye lens array comprises a plurality of focusing lenses, the focusing lenses are in one-to-one correspondence with the pixel elements, and the fly-eye lens array is used for receiving the first image and outputting a second image to the photosensitive material surface;

the controller is used for controlling the light source to expose, and each exposure generates the light beam image once.

2. The imaging system of a light curable 3D printing device according to claim 1, wherein the beam image comprises a sub-beam image corresponding to each pixel element, the first image comprises a first sub-image corresponding to each of the sub-beam images, the second image comprises a second sub-image corresponding to each of the first sub-images, each of the first sub-images has a first energy distribution width, each of the second sub-images has a second energy distribution width, and the second energy distribution width is narrower than the first energy distribution width.

3. The imaging system of a light curable 3D printing device of claim 2, further comprising a projection lens disposed between the fly eye lens array and the photosensitive material surface, the projection lens to magnify the second image and output a third image to the photosensitive material surface.

4. The imaging system of a light curable 3D printing device of claim 3, wherein the third image comprises a third sub-image corresponding to each of the second sub-images, each of the third sub-images having a third energy distribution width, the third energy distribution width being wider than the second energy distribution width.

5. The imaging system of a light curable 3D printing device of claim 2, wherein the controller is further configured to control the imaging element, the relay lens and the fly eye lens array to move together at each exposure to project the second image corresponding to each exposure to a different location of the photosensitive material surface.

6. The imaging system of a light-curable 3D printing device of claim 5, wherein the second sub-images corresponding to each exposure do not overlap each other on the surface of the photosensitive material.

7. The imaging system of a light-curable 3D printing device of claim 5, wherein the second sub-image corresponding to each exposure is spread over the photosensitive material surface.

8. The imaging system of the light curable 3D printing device of claim 4, wherein the controller is further configured to control the imaging element, the relay lens, and the fly-eye lens array to move together at each exposure to project the third image corresponding to each exposure to a different location of the photosensitive material surface.

9. The imaging system of a light-curable 3D printing device of claim 8, wherein the third sub-images corresponding to each exposure do not overlap each other on the surface of the photosensitive material.

10. The imaging system of a light-curable 3D printing device of claim 8, wherein the third sub-image corresponding to each exposure is spread over the photosensitive material surface.

11. The imaging system of a light curable 3D printing device of claim 1, wherein the imaging element comprises a transmissive imaging element.

12. The imaging system of a light curable 3D printing device of claim 3, wherein the imaging element comprises a reflective imaging element.

13. The imaging system of a photo-curing 3D printing apparatus of claim 1, wherein the beam images of each exposure contain the same image information.

14. The imaging system of a photo-curing 3D printing apparatus of claim 1, wherein the beam image of each exposure contains different image information.

15. A photo-curable 3D printing device comprising the imaging system of any of claims 1-14.