3D PRINTED OPTICS

Abstract

The invention provides a method for manufacturing a 3D item (1) by means of fused deposition modelling, wherein the 3D item (1) is a multi-arm light guide having an articulated body of at least two connected body elements (310), wherein each body element (310) is an arm of the multi-arm light guide, wherein each body element (310) has a first end (311) and a second end (312), wherein the first ends (311) of the connected body elements (310) are for incoupling of light in the multi-arm light guide, wherein the second ends (312) of the connected body elements (310) diverge from each other and are for outcoupling of light from the multi-arm light guide, wherein the method comprises a 3D printing stage wherein an extrudate (321) comprising a 3D printable material (201) is deposited in a layer-wise manner to provide the 3D item (1) comprising a 3D printed material (202); wherein the 3D printable material (201) comprises a light transmissive material; wherein the 3D item (1) comprises one or more layers (322) of the 3D printed material (202), wherein each of the connected body elements (310) comprises at least two adjacent 3D printed layer parts (1322); wherein the method comprises:—for each of the body elements (310) printing a single continuous layer part (2322) comprising the at least two adjacent 3D printed layer parts (1322), wherein the printing of the single continuous layer part (2322) involves printing in a first direction and then turning back and printing back in a second direction opposite to the first direction to provide a first body element U-turn (313) at the first end (311) of the body element (310); and—connecting adjacent body elements (310) by one or more of (i) merging parts of the adjacent body elements (310), (ii) 3D printing a connection element (320) connecting the adjacent body elements (310), and (iii) 3D printing the single continuous layer part (2322) comprising the 3D printed layer parts (1322) of the adjacent body elements (310).

Claims

1. A method for manufacturing a 3D item by means of fused deposition modelling, wherein the 3D item is a multi-arm light guide having an articulated body of at least two connected body elements, wherein each body element is an arm of the multi-arm light guide, wherein each body element has a first end and a second end, wherein the first ends of the connected body elements are for incoupling of light in the multi-arm light guide, wherein the second ends of the connected body elements diverge from each other and are for outcoupling of light from the multi-arm light guide, wherein the method comprises a 3D printing stage wherein an extrudate comprising a 3D printable material is deposited in a layer-wise manner to provide the 3D item comprising a 3D printed material (202); wherein the 3D printable material comprises a light transmissive material; wherein the 3D item comprises one or more layers of the 3D printed material, wherein each of the connected body elements comprises at least two adjacent 3D printed layer parts; wherein the method comprises: for each of the body elements printing a single continuous layer part comprising the at least two adjacent 3D printed layer parts, wherein the printing of the single continuous layer part involves printing in a first direction and then turning back and printing back in a second direction opposite to the first direction to provide a U-turn at the first end of the body element; and connecting adjacent body elements by one or more of (i) merging parts of the adjacent body elements, (ii) 3D printing a connection element connecting the adjacent body elements, and (iii) 3D printing the single continuous layer part comprising the 3D printed layer parts of the adjacent body elements.

2. The method according to claim 1, wherein the printing of the single continuous layer part involves printing in a third direction and then turning back and printing back in a fourth direction opposite to the third direction to provide a U-turn at the second end of the body element.

3. The method according to claim 2, comprising providing the U-turn at the second end with a flattened face of which at least part is perpendicular to a plane of printing.

4. The method according to claim 1, wherein the connecting of adjacent body elements is done by merging parts of two adjacent body elements at first positions closer to the first ends of the body elements than to the second ends.

5. The method according to claim 1, wherein the connecting of adjacent body elements is done by 3D printing the connection element connecting the body elements of two adjacent body elements at second positions closer to the second ends of the adjacent body elements than to the first ends.

6. The method according to claim 1, comprising 3D printing the at least two connected body elements around a cavity.

7. The method according to claim 1, comprising printing the one or more layers of 3D item as one or more single continuous layer parts, wherein each of the layer parts are comprised by the one or more single continuous layer parts, wherein the layers have layer heights and layer widths selected from the range of 0.5-5 cm.

8. The method according to claim 1, comprising layer-wise depositing a plurality of the layers along a height perpendicular to a plane of printing, to provide an elongated 3D item.

9. The method according to claim 1, wherein the 3D printable material and the 3D printed material comprise one or more of polycarbonate, polyethylene naphthalate, styrene-acrylonitrile resin, polysulfone, polytethylene terephthalate and its copolymers, acrylonitrile butadiene styrene, poly(methyl methacrylate), polystyrene, styrene acrylic copolymers, and polyurethane.

10. A multi-arm light guide having an articulated body of at least two connected body elements, wherein each body element is an arm of the multi-arm light guide, wherein each body element has a first end and a second end, wherein the first end is for incoupling of light in the multi-arm light guide, wherein the second ends of the connected body elements diverge from each other and are for outcoupling of light from the multi-arm light guide, wherein the multi-arm light guide is a 3D item comprising 3D printed material, and wherein the 3D item is obtainable by the method according to claim 1.

11. The multi-arm light guide according to claim 10, wherein the at least two adjacent 3D printed layer parts of each of the body elements are comprised by a single continuous layer part with a U-turn at the second ends of the at least two adjacent 3D printed layer parts, wherein the U-turns at the second ends have a flattened face perpendicular to an axis of elongation of the respective body elements.

12. The multi-arm light guide according to claim 10, comprising the connection element connecting the body elements of two adjacent the body elements at second positions closer to the second ends of the body elements than to the first ends, wherein the at least two connected body elements are arranged around a cavity, and wherein the one or more layers of 3D item are one or more single continuous layer parts, wherein the layers have layer heights and layer widths selected from the range of 0.5-5 cm.

13. A lighting device comprising the multi-arm light guide according to claim 10, and a light source configured to generate light source light, wherein the two or more U-turns at the first end are configured in a light receiving relationship with the light source so that light source light can be coupled into the multi-arm light guide via the two or more U-turns at the first end.

14. The lighting device according to claim 13, wherein the light source is at least partially configured in the cavity of the multi-arm light guide.

15. A software product when running on a computer which is functionally coupled to or comprised by a fused deposition modeling 3D printer is capable of bringing about the method as described in claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0095] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

[0096] FIGS. 1a-1c schematically depict some general aspects of the 3D printer and of an embodiment of 3D printed material;

[0097] FIGS. 2a-2b schematically depict some aspects;

[0098] FIGS. 3a-3d, 4a-4b, 5a-5b, 6a-6b, 7a-7b, and 8a-8c schematically depict various embodiments and variants.

[0099] The schematic drawings are not necessarily to scale.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0100] FIG. 1a schematically depicts some aspects of the 3D printer. Reference 500 indicates a 3D printer. Reference 530 indicates the functional unit configured to 3D print, especially FDM 3D printing; this reference may also indicate the 3D printing stage unit. Here, only the printer head for providing 3D printed material, such as a FDM 3D printer head is schematically depicted. Reference 501 indicates the printer head. The 3D printer of the present invention may especially include a plurality of printer heads, though other embodiments are also possible. Reference 502 indicates a printer nozzle. The 3D printer of the present invention may especially include a plurality of printer nozzles, though other embodiments are also possible. Reference 321 indicates a filament of printable 3D printable material (such as indicated above). For the sake of clarity, not all features of the 3D printer have been depicted, only those that are of especial relevance for the present invention (see further also below).

[0101] The 3D printer 500 is configured to generate a 3D item 1 by layer-wise depositing on a receiver item 550, which may in embodiments at least temporarily be cooled, a plurality of filaments 321 wherein each filament 310 comprises 3D printable material 201, such as having a melting point T.sub.m. The 3D printable material 201 may be deposited on a substrate 1550 (during the printing stage).

[0102] The 3D printer 500 is configured to heat the filament material upstream of the printer nozzle 502. This may e.g. be done with a device comprising one or more of an extrusion and/or heating function. Such device is indicated with reference 573, and is arranged upstream from the printer nozzle 502 (i.e. in time before the filament material leaves the printer nozzle 502). The printer head 501 may (thus) include a liquefier or heater. Reference 201 indicates printable material. When deposited, this material is indicated as (3D) printed material, which is indicated with reference 202.

[0103] Reference 572 indicates a spool or roller with material, especially in the form of a wire, which may be indicated as filament 320. The 3D printer 500 transforms this in a filament 321 downstream of the printer nozzle which becomes a layer 322 on the receiver item or on already deposited printed material. In general, the diameter of the filament 321 downstream of the nozzle is reduced relative to the diameter of the filament 322 upstream of the printer head. Hence, the printer nozzle is sometimes (also) indicated as extruder nozzle. Arranging layer 322 by layer 322 and/or layer 322t on layer 322, a 3D item 1 may be formed. Reference 575 indicates the filament providing device, which here amongst others include the spool or roller and the driver wheels, indicated with reference 576.

[0104] Reference A indicates a longitudinal axis or filament axis.

[0105] Reference C schematically depicts a control system, such as especially a temperature control system configured to control the temperature of the receiver item 550. The control system C may include a heater which is able to heat the receiver item 550 to at least a temperature of 50° C., but especially up to a range of about 350° C., such as at least 200° C.

[0106] Alternatively or additionally, in embodiments the receiver plate may also be moveable in one or two directions in the x-y plane (horizontal plane). Further, alternatively or additionally, in embodiments the receiver plate may also be rotatable about z axis (vertical). Hence, the control system may move the receiver plate in one or more of the x-direction, y-direction, and z-direction.

[0107] Alternatively, the printer can have a head can also rotate during printing. Such a printer has an advantage that the printed material cannot rotate during printing.

[0108] Layers are indicated with reference 322, and have a layer height H and a layer width W.

[0109] Note that the 3D printable material is not necessarily provided as filament 320 to the printer head. Further, the filament 320 may also be produced in the 3D printer 500 from pieces of 3D printable material.

[0110] Reference D indicates the diameter of the nozzle (through which the 3D printable material 201 is forced).

[0111] FIG. 1b schematically depicts in 3D in more detail the printing of the 3D item 1 under construction. Here, in this schematic drawing the ends of the filaments 321 in a single plane are not interconnected, though in reality this may in embodiments be the case. Reference H indicates the height of a layer. Layers are indicated with reference 203. Here, the layers have an essentially circular cross-section. Often, however, they may be flattened, such as having an outer shape resembling a flat oval tube or flat oval duct (i.e. a circular shaped bar having a diameter that is compressed to have a smaller height than width, wherein the sides (defining the width) are (still) rounded).

[0112] Hence, FIGS. 1a-1b schematically depict some aspects of a fused deposition modeling 3D printer 500, comprising (a) a first printer head 501 comprising a printer nozzle 502, (b) a filament providing device 575 configured to provide a filament 321 comprising 3D printable material 201 to the first printer head 501, and optionally (c) a receiver item 550. In FIGS. 1a-1b, the first or second printable material or the first or second printed material are indicated with the general indications printable material 201 and printed material 202. Directly downstream of the nozzle 502, the filament 321 with 3D printable material becomes, when deposited, layer 322 with 3D printed material 202.

[0113] FIG. 1c schematically depicts a stack of 3D printed layers 322, each having a layer height H and a layer width W. Note that in embodiments the layer width and/or layer height may differ for two or more layers 322. Reference 252 in FIG. 1c indicates the item surface of the 3D item (schematically depicted in FIG. 1c).

[0114] Referring to FIGS. 1a-1c, the filament of 3D printable material that is deposited leads to a layer having a height H (and width W). Depositing layer 322 after layer 322, the 3D item 1 is generated.

[0115] As indicated above, amongst others herein various printing strategies for printing a wave guided beam shaping optics for obtaining the desired optical effect are described. Best results were obtained when the wave guide plate entrance had a single curve and exit surface was as flat as possible. The presence of the ribbed structure, due to the availability of stacked layers, also helped spreading the beam removing the spotty appearance. In a desirable configuration the wave guide elements get connected to each other forming a self-supporting luminaire where the surfaces of the waveguide are protected against dust and other dirt. Furthermore, it makes it possible to combine different wave plate configurations in such a luminaire in order to produce different light distributions from different parts of the luminaire.

[0116] Amongst others, we suggest the use of multi arm distributed wave guides to obtain any desired beam shape in the far field. Multiple wave guides can be placed above a light source for coupling light into these light guides. The orientation of the end of the wave guides can then be aligned in a desired manner to obtain the desired light distribution. FIG. 2a schematically depicts a possible wave guide design. The theoretical beam shape which could be obtained from such a wave guide is shown in FIG. 2b. FIG. 2b shows that a so-called bat wing type of light distribution can be obtained from such a wave guide arrangement placed above the LED strip. A LED strip is an example of a light source 10. The light source 10 may at least partly be configured in a cavity 350.

[0117] It may be desirable to produce such a wave guide arrangement using FDM printing. FIG. 3a schematically shows the orientation of the object with respect to the built plate. This orientation is especially chosen so that the layers are produced in the direction of the waveguide defining the light propagation. Hence, the body elements, indicated with references 310, of the articulate body may be printed layer by layer with an axis of elongation A1 of the body elements parallel to the built plate and the printing direction/printing plane.

[0118] When a nozzle with a size smaller than the size of the details are used flat edges and sharp corners. However, printing with a small nozzle results in printing times which are commercially not interesting. For this reason, amongst others a spiralized printing strategy is herein suggested, where the printer follows continuously a path. Especially, when a relatively large nozzle (1.8 mm diameter) leading to layer width W which is about the same size as the nozzle diameter is used, sharp and straight side edges present in the original design may become curved. The layer height H is indicated in FIG. 3a.

[0119] As the method may comprise layer-wise depositing a plurality of the layers 322 along a height H1 (item height H1) perpendicular to a plane of printing, to provide an elongated 3D item 1, in FIG. 3a such item with height H1 is depicted. The layers 322 may provide a ribbed structure (which is in this schematic drawing not indicated, but the lines between layers at the side face may e.g. be interpreted as (small) indentations between ribs.

[0120] FIG. 3b schematically depicts a geometry of the 3D item. Reference 311 indicates a first end of the body elements 310 and reference 312 indicates a second end of the body elements 310. The latter may also be indicated as a terminal end of the body element 310.

[0121] Below various printing strategies for printing such a wave guided beam shaping optics (for obtaining the desired optical effect) are described and compared. Amongst others such as continues in plane printing followed by a vertical move print the subsequent layer, so-called spiralize printing was applied, where the nozzle moves in the x-y plane and after each movement the stage (or built plate) moves downwards in z direction. For measuring light distribution from the waveguide a LED placed underneath the waveguide plate and the light intensity was measured as a function of angle as indicated in FIG. 3b

[0122] In a first design 1, separate wave guide elements or body elements 310 are touching each other, see FIG. 3c. In FIG. 3c schematically the movement of the printer head as it moves to move to print one wave guide element is shown and the thus obtained item 1 is (also) shown.

[0123] FIG. 3c also shows how in practice a method for producing a 3D item 1 by means of fused deposition modelling, the method comprising a 3D printing stage comprising depositing an extrudate 321 comprising 3D printable material 201, to provide the 3D item 1 comprising 3D printed material 202 may be executed. As indicated above, the 3D printable material 201 comprises light transmissive material. The 3D item 1 comprises one or more layers 322; here, only one layer is depicted. Perpendicular to the plane of drawing, further layers 322 may be provided of the 3D printed material 202. As indicated above, consequently the 3D printed material 202 comprises light transmissive material

[0124] The 3D item 1 comprises an articulated body of at least two connected body elements 310, each having a first end 311 and a second end 312. The second ends 312 diverge from each other. Each of the connected body elements 310 comprises at least two adjacent 3D printed layer parts 1322.

[0125] Especially, the method comprises for each of the body elements 310 printing a single continuous layer part 2322 comprising the at least two adjacent 3D printed layer parts 1322 with a first body element U-turn 313 at the first end 311.

[0126] Further, the method may comprise connecting adjacent body elements 310 by one or more of (i) merging parts of the adjacent body elements 310, (ii) 3D printing a connection element 320 connecting the adjacent body elements 310, and (iii) 3D printing the single continuous layer part 2322 comprising the 3D printed layer parts 1322 of the adjacent body elements 310. Here, adjacent body elements 310 are merged together, at a position closer to the first end than to the second end. Several layer heights for the 3D printed layers 322 were chosen, amongst others 0.4 mm and 0.6 mm. Reference 314 indicates a connection (especially by merging).

[0127] FIG. 3c also shows that the (two) adjacent 3D printed layer parts especially refers to parts that are 3D printed over at least part of their length in physical contact with each other and/or partly merged.

[0128] FIGS. 3b and 3c also show that the axes of elongation may be straight or curved, or comprise straight parts and curved parts.

[0129] For the former, the luminous intensity distribution is shown in FIG. 3d. For the latter the intensity distribution is essentially the same. FIG. 3d shows the light intensity as a function of angle theta the version with a layer height of 0.4 mm. Hence, a batwing pattern can be obtained.

[0130] In another design, see FIG. 4a, a connected wave guide printing in a true spiralized way where the printer head moves in one closed loop. Here the entrance surface (at the first end 311) is smooth and continuous for all waveguide segments. Note that the body element 310 does not have a U-turn at the first ends of the arms. FIG. 4b shows the luminous intensity as a function of angle theta. In FIG. 4b it can be seen that the batwing pattern is essentially not available. This may not be desired for specific applications.

[0131] In yet another design, see FIG. 5a, a connected wave guide printing in a true spiralized way is schematically depicted, where the printer head moves in one closed loop. In this figure it can be seen that the entrance of the waveguide is split. Hence, also here no U-turn is available at the first end. FIG. 5b shows the luminous intensity as a function of angle theta. In FIG. 5b it can be seen that also here the batwing pattern is absent.

[0132] In yet a further design (modified design 1; see also FIG. 3c), the exit surfaces were flat as shown; see FIG. 6a.

[0133] FIG. 6a (but also FIGS. 3c, 4a, and 5a) shows an embodiment with at the second end 312 a second body element U-turn 343. FIG. 6a especially shows an embodiment comprising the second body element U-turn 343 which comprises a flattened face 344 of which at least part is perpendicular to a plane of printing. FIG. 6b shows the luminous intensity as function of the angle theta. In FIG. 6b it can be seen that the batwing pattern is more prominent than the one obtained for design of FIG. 3c.

[0134] Referring to FIGS. 5a and 6a/7a, especially, at the first end there is a single U-turn 313 defined by two adjacent printed layer parts (see FIG. 6a/7a, or a single U-turn comprising or enclosing parts of a plurality of at least two adjacent printed layer parts. When the first end is defined by (at least) two U-turns of (at least) two adjacent printed layer parts (see FIG. 5a), light incoupling appears to be less efficient and/or the luminous intensity distribution is less desirable.

[0135] In order to make a self-supporting luminaire where the surfaces of the waveguide is protected against dust and other dirt, wave guide is elements were connected to each other and platform was created to place a led strip and align the LEDs with respect to the wave guides. In FIG. 7a a connected wave guide printing in a true spiralized way is shown, where the printer head moves in one closed loop. The luminous intensity as function of theta is shown in FIG. 7b. It can be seen that such a wave guide luminaire shows a batwing light distribution.

[0136] FIG. 7a also schematically shows an embodiment, or the result thereof, wherein the method comprising 3D printing a connection element 320 connecting the body elements 310 of two adjacent body elements 310 at second positions 352 closer to the second ends 312 of the adjacent body elements 310 than to the first ends 311. FIG. 7a also schematically shows an embodiment, or the result thereof, of a method comprising 3D printing the at least two connected body elements 310 around a cavity 350.

[0137] FIG. 7a also schematically depicts an embodiment of a lighting device 1000 comprising the 3D item 1 and the light source 10. The light source 10 is configured to generate light source light 11. Further, especially the two or more first body element U-turns 313 are configured in a light receiving relationship with the light source 10. Further, an embodiment is schematically depicted wherein the light source 10 is at least partially configured in the cavity 350 of the 3D printed item 1.

[0138] FIG. 8a schematically depicts an embodiment with two body elements 310, each comprising 3D printed layer parts 1322 in three layers 322 (though they do not necessarily comprise the same number of layers 322), wherein connection element 320 connecting the adjacent body elements 310 is only available between adjacent 3D printed layer parts in one or two of the three layers 322, whereas the adjacent 3D printed layer parts within the two ore one layers 322 are not connected.

[0139] FIG. 8b schematically depicts an embodiment with two body elements 310, each comprising 3D printed layer parts 1322 in three layers 322 (though they do not necessarily comprise the same number of layers 322), wherein a connection 314 by merging is provided due to a merging of two adjacent 3D printed layer parts in the middle layer 322, whereas the adjacent 3D printed layer parts within the lowest and the highest layer 322 are not connected.

[0140] Hence, the fact that adjacent body elements 310, each comprising a stack of 3D printed layer parts within different layers on top of each other, does not necessarily imply that within each level or layer 322 the body elements 310 are connected by merging or a connection element (or are comprised in each layer by a single continues layer part).

[0141] FIG. 8c schematically depicts that a body element 310 (within a single layer) may comprise more than two adjacent 3D printed layer parts, e.g. by printing hence and forth and around the hence and forth 3D printed two adjacent 3D printed layer parts 1322. Hence, the U-curve 313 at the first end may be provided by at least three layer parts 1322.

[0142] FIG. 8c also shows that the at least two adjacent 3D printed layer parts especially refers to parts that are 3D printed over at least part of their length in physical contact with each other and/or partly merged.

[0143] The embodiment of FIG. 8c also shows that when the body element 310 comprises more than two adjacent 3D printed layer parts 1322, a U-turn 313 comprising a plurality of U-turns may be provided; this may especially be the case when the body element 310 comprises at least four, or especially at least five adjacent 3D printed layer parts 1322.

[0144] It is also possible to combine wave guide configurations in a single luminaire in order to produce different light distributions from different parts. Therefore it is possible to have different arm lengths and/or orientations along the print.

[0145] The term “substantially” herein, such as “substantially consists”, will be understood by the person skilled in the art. The term “substantially” may also include embodiments with “entirely”, “completely”, “all”, etc. Hence, in embodiments the adjective substantially may also be removed. Where applicable, the term “substantially” may also relate to 90% or higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or higher, including 100%. The term “comprise” includes also embodiments wherein the term “comprises” means “consists of”. The term “and/or” especially relates to one or more of the items mentioned before and after “and/or”. For instance, a phrase “item 1 and/or item 2” and similar phrases may relate to one or more of item 1 and item 2. The term “comprising” may in an embodiment refer to “consisting of” but may in another embodiment also refer to “containing at least the defined species and optionally one or more other species”.

[0146] Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

[0147] The devices herein are amongst others described during operation. As will be clear to the person skilled in the art, the invention is not limited to methods of operation or devices in operation.

[0148] It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb “to comprise” and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0149] The invention also provides a control system that may control the apparatus or device or system, or that may execute the herein described method or process. Yet further, the invention also provides a computer program product, when running on a computer which is functionally coupled to or comprised by the apparatus or device or system, controls one or more controllable elements of such apparatus or device or system.

[0150] The invention further applies to a device comprising one or more of the characterizing features described in the description and/or shown in the attached drawings. The invention further pertains to a method or process comprising one or more of the characterizing features described in the description and/or shown in the attached drawings.

[0151] The various aspects discussed in this patent can be combined in order to provide additional advantages. Further, the person skilled in the art will understand that embodiments can be combined, and that also more than two embodiments can be combined. Furthermore, some of the features can form the basis for one or more divisional applications.

[0152] It goes without saying that one or more of the first (printable or printed) material and second (printable or printed) material may contain fillers such as glass and fibers which do not have (to have) influence on the on T.sub.g or T.sub.m of the material(s).