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Title:
METHOD OF RAPID PROTOTYPING A BRISTLE FIELD FOR A TOOTHBRUSH
Document Type and Number:
WIPO Patent Application WO/2019/102044
Kind Code:
A1
Abstract:
A method of rapid prototyping a bristle field (22) for a toothbrush (10) comprises performing, via a 3D printer, or additive manufacturing (AM) a positive layer-by-layer deposition of bristle fabrication material onto a platen (24). The positive layer-by-layer deposition includes deposition of the bristle fabrication material in desired xyz locations according to a bristle field pattern of bristles to produce a desired bristle field. The desired bristle field (22) at least one of a variety of bristles (30, 32, 34, 36, 38, 39) having cross- sectional diameters of various dimensions along the length dimension thereof.

Inventors:
DENGLER, Evan, Dak, Wah (High Tech Campus 5, 5656 AE Eindhoven, 5656 AE, NL)
LEE, Sungsoo (High Tech Campus 5, 5656 AE Eindhoven, 5656 AE, NL)
Application Number:
EP2018/082749
Publication Date:
May 31, 2019
Filing Date:
November 27, 2018
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
KONINKLIJKE PHILIPS N.V. (High Tech Campus 5, 5656 AE Eindhoven, 5656 AE, NL)
International Classes:
A46D1/00; B33Y10/00; B33Y80/00
Domestic Patent References:
WO2017075616A12017-05-04
WO2018060767A12018-04-05
Foreign References:
US20130276812A12013-10-24
US20140325776A12014-11-06
Other References:
None
Attorney, Agent or Firm:
DE HAAN, Poul, Erik (Philips International B.V. – Intellectual Property & Standards High Tech Campus 5, 5656 AE Eindhoven, 5656 AE, NL)
Download PDF:
Claims:
CLAIMS:

1. A method of rapid prototyping one or more bristles (30, 32, 34, 36, 38, 39) for a toothbrush (10) brush head (18), the method comprising:

performing, via a 3D printer, a positive layer-by-layer deposition of at least one bristle fabrication material onto a brush platen (24), to produce a desired bristle field (22), the bristles having cross-sectional diameters of various dimensions along a length dimension thereof.

2. The method of claim 1 wherein the bristles (30) have a decreasing cross-sectional diameter along the length dimension from a base (26) at the platen (24) end to a tip (28) of the respective bristles, wherein the decreasing cross-sectional diameter along the length dimension thereof is implemented via varying a cross-sectional diameter of material deposition between subsequent, immediately adjacent, deposition layers in one of a steady continuous decreasing manner, or an accelerated continuous decreasing manner, of the at least one bristle fabrication material.

3. The method of claim 1 wherein the bristles (32) have cross-sectional diameters of various dimensions (32a, 32b, 32c) along the length dimension thereof, from a base (26) to a tip (28) thereof, such that a pattern of the cross-sectional diameters forms at least one bending hinge (40) of the respective bristles the dimensions of cross-sectional diameters of the at least one bristle fabrication material being varied along the length dimension thereof via varying a cross-sectional diameter of material deposition between subsequent, immediately adjacent, deposition layers in a decreasing manner, an increasing manner, or an unchanging manner.

4. The method of claim 1 wherein the bristles (34) have various curvatures along a length dimension, from a base portion (26) to a tip portion (28) thereof, wherein the various curvatures are implemented via varying at least one of a horizontal or a vertical offset (34’) in a location of material deposition between subsequent, immediately adjacent, deposition layers of the at least one bristle fabrication material for respective bristles.

5. The method of claim 1 wherein the bristles (36) have a varying curvature along the length dimension from a base (26) at the platen (24) end to a tip (28) of the respective bristles, wherein the varying curvature is implemented via varying at least one of a horizontal or vertical offset in location of material deposition between subsequent, immediately adjacent, deposition layers (36’), of the at least one bristle fabrication material.

6. The method of claim 5 wherein the horizontal or vertical offset is less than 50% of a horizontal or vertical cross-sectional diameter of an immediately prior formed deposition layer.

7. The method of claim 1 wherein the bristle (38) have cross-sectional diameters of various dimensions (38a, 38b) along the length dimension thereof, and a transition region (38’) that forms a sharp angle between a base portion (26) and a tip portion (28) thereof along its length dimension achieved by varying the horizontal offset between adjoining layers of deposited bristle fabrication material.

8. The method of claim 1 wherein the bristles (39) have cross-sectional diameters of various dimensions along the length thereof, from a base (26) to a tip (28) thereof, such that a pattern of the deposition layers forms at least one bulge (39d) on the respective bristle, the bulge having at least one of a larger height or a larger cross-sectional diameter than the other deposition layers (39e) of the bristle.

9. A toothbrush (10) having a brush head (18) comprised of one or more bristle tufts (20) having at least one bristle (30, 32, 34, 36, 38, 39) made by 3D layer-by-layer deposition of at least one bristle fabrication material onto a brush platen (24) to produce a desired bristle field (22), the bristles having cross-sectional diameters of various dimensions along the length dimension from a base (26) to a tip (28) thereof.

10. The toothbrush of claim 9 wherein the bristle field includes bristles of a smaller cross-sectional diameter along a length dimension thereof on exterior side regions of the bristle field, and bristles of a larger cross-sectional diameter along a length dimension thereof in an interior central region of the bristle field.

11. The toothbrush of claim 9 wherein the bristle field includes a lesser density of bristles positioned on exterior regions of the bristle field (22), and a greater density of bristles positioned within an interior region of the bristle field.

12. The toothbrush of claim 9, wherein the bristle field further includes (a) two arrays of tall bristles (34) curved along a length dimension thereof, positioned on exterior regions of the bristle field, with curved bristles of a first array on one side edge of the bristle field facing curved bristles of a second array on an opposite side edge of the bristle field, and (b) an array of shorter, straight bristles positioned within an interior region of the bristle field.

13. The toothbrush of claim 9 wherein at least one of the bristle tufts have a texture (86) formed on an outer surface thereof during layer deposition, to assist in scraping plaque from teeth.

14. The toothbrush of claim 9 wherein at least one of the bristle tufts have a texture (88) formed on an outer surface thereof during layer deposition to massage gums.

Description:
METHOD OF RAPID PROTOTYPING A BRISTLE FIELD FOR A TOOTHBRUSH

[0001] The present embodiments relate generally to rapid prototyping and more particularly, to a method of rapid prototyping a bristle field for a toothbrush.

[0002] In the current state of the art, bristles are currently produced via a chemical removal process in which the outer diameter of a plastic bristle is etched away due to exposure to a corrosive or etchant bath. The longer the exposure time, the more material gets removed. Tapered bristles are submerged to a certain depth within the etchant bath, and then slowly extracted from the etchant bath. This results in a sharp conical tip bristle. Such a chemical removal process and method is limited in its ability to form bristles with varying characteristics.

[0003] Also in the current state of the art, bristles are produced via an extrusion process where hot nylon chips are melted and drawn through a spinneret. This results in a bristle with a very consistent diameter along the entire length. However, such an extrusion process is limited in its ability to form bristles with varying characteristics.

[0004] In another embodiment of the current state of the art, curved bristles are produced as follows. After being inserted into a brush neck, a heat application is applied to form the bristles into a desired curved shape.

[0005] In yet another embodiment of the current state of the art, textured bristles are produced as follows. After being extruded in a normal bristle production process, the bristle is put through a roller die which compresses the bristle to have periodic bulges in the outer shape, i.e., on an exterior of the bristle along its length.

[0006] In a still further embodiment of the current art, in order to fabricate variable density bristle fields, bristles are normally inserted into the brush neck as a tuft, i.e., a group of adjacent bristles. The bristles within a tuft are typically packed together as tightly as possible for a high bristle density. This high bristle density assists in function (i.e., since more bristles means more contact area and thus higher cleaning efficiency), but is mainly done for manufacturability (i.e., a bristle picker doesn’t drop loose strands of bristles) and tuft retention (i.e., any gaps in bristle field mean the retention is looser and less secure). In addition, with current designs, both height and diameter of bristles are tuned to get optimal function and in-mouth feel. However, such a process of varying both height and diameter of bristles is complex. [0007] Rapid prototyping technology is a rapidly growing field and is excellent at creating large macroscale objects, but has significant difficulties with objects that have large aspect ratios (i.e., tall and thin objects). Very small, thin objects, such as bristles, are among the most difficult challenges, especially if no support material is used.

[0008] Accordingly, an improved method and apparatus for overcoming the problems in the art is desired.

[0009] In accordance with one aspect, a novel method for rapid prototyping of a brush head, as disclosed herein, advantageously overcomes a main difficult part of rapid prototyping a bristle field, which comprises the very densely packed high aspect ratio shapes in the brush head of a toothbrush.

[0010] The embodiments of the present disclosure make use of technology that allows for the production of bristles using a conventional Digital Light Processing (DLP) 3D printer (e.g., an Autodesk Ember Printer. Now that this rapid prototyping technology exists, further innovations become feasible. The smallest bristle capable of being produced by this method is 100 micron, which is about a 4 mil diameter bristle, which is about the smallest diameter bristle currently being used in production brush heads.

[0011] In accordance with one aspect, a method of rapid prototyping of a bristle field for a toothbrush comprises: performing, via a 3D printer or additive manufacturing (AM), a positive layer-by-layer deposition of at least one bristle fabrication material onto a brush platen, wherein the positive layer-by-layer deposition include deposition of the at least one bristle fabrication material in desired xyz locations according to a bristle field pattern of bristles to produce a desired bristle field. This is especially important when the bristle field includes two or more mechanisms of bristles selected from the group consisting of (i) tapered and/or end rounded bristles with a decreasing cross-sectional diameter along a length dimension of the respective bristles from a base to a tip of the respective bristles, (ii) bristles having cross-sectional diameters of various dimensions along a length dimension thereof, from a base to a tip of the respective bristles, including a pattern of the cross- sectional diameters that forms at least one of (I) a bending hinge of the respective bristles and (II) bristles with periodic bulges along the length dimension thereof, (iii) bristles having various curvatures along a length dimension thereof, from a base portion to a tip portion of the respective bristles, (iv) bristles of variable diameters in a bristle field, and (v) variable densities of bristles in a bristle field.

[0012] With respect to the tapered and/or end-rounded bristles with a decreasing cross- sectional diameter along a length dimension of the respective bristles from a base to a tip of the respective bristles, the decreasing cross-sectional diameter along the length dimension thereof is implemented via varying a cross-sectional diameter of material deposition between subsequent, immediately adjacent, deposition layers in one of (i) a steady continuous decreasing manner (i.e., rate of decreasing change remains constant), and (ii) an accelerated continuous decreasing manner (i.e., rate of decreasing change is not constant, but increases with subsequent, immediately adjacent deposition layers), of the at least one bristle fabrication material for respective bristles.

[0013] With respect to the bristles having cross-sectional diameters of various dimensions along a length dimension thereof, from a base to a tip of the respective bristles, including (ii)(a) a pattern of the cross-sectional diameters that forms at least one of (ii)(a)(l) a bending hinge of the respective bristles and (ii)(a)(2) bristles with periodic bulges along the length dimension thereof, the dimensions of cross-sectional diameters of the at least one bristle fabrication material for respective bristles (ii)(b) are varied along the length dimension thereof via varying a cross-sectional diameter of material deposition between subsequent, immediately adjacent, deposition layers in two or more of (ii)(b)(l) a decreasing manner, (ii)(b)(2) an increasing manner, and (ii)(b)(3) an unchanging manner.

[0014] With respect to the bristles having various curvatures along a length dimension thereof, from a base portion to a tip portion of the respective bristles, the various curvatures along the length dimension thereof are implemented via varying an offset in a location of material deposition between subsequent, immediately adjacent, deposition layers of the at least one bristle fabrication material for respective bristles. With respect to the bristles of variable diameters in a bristle field, the bristle field includes (iv)(a) bristles of smaller cross-sectional diameter along the length dimension thereof positioned on exterior side regions of the bristle field, and (iv)(b) bristles of larger cross-sectional diameter along the length dimension thereof positioned within an interior central region of the bristle field. Lastly, with respect to variable densities of bristles in a bristle field, the bristle field includes (v)(a) a lesser density of bristles positioned on exterior regions of the bristle field, and (v)(b) a greater density of bristles positioned within an interior region of the bristle field.

[0015] In one embodiment, the method comprises the step of wherein the two or more brushing guidance features and/or mechanisms of bristles include bristles having cross- sectional diameters of various dimensions along the length dimension thereof, and wherein the at least one bending hinge is operable to provide a desired bristle motion and resonance of the respective bristle. In another embodiment, the method further includes wherein the desired bristle motion and resonance of the respective bristle comprises a plaque removal bristle motion and resonance originating at a base of the respect bristle and being transferred, via the bending hinge, to a tip of the respective bristle.

[0016] In another embodiment, the method comprises the step of wherein the two or more brushing guidance features and/or mechanisms of bristles include bristles having cross-sectional diameters of various dimensions along the length dimension thereof, and wherein the bristles with periodic bulges along the length dimension thereof include surface bumps and textures that comprise vertical depositions of (i) small height, small cross-sectional diameter with zero offset depositions of the at least one bristle fabrication material and (ii) large height, large cross-sectional diameter with overhang offset depositions of the at least one bristle fabrication material.

[0017] According to another embodiment, the method comprises wherein the two or more brushing guidance features and/or mechanisms of bristles include bristles having various curvatures along the length dimension thereof, and wherein the offset includes at least one of (a) a horizontal offset, and (b) both a horizontal and a vertical offset.

According to yet another embodiment, the method comprises wherein the two or more brushing guidance features and/or mechanisms of bristles include bristles having various curvatures along the length dimension thereof, wherein the offset is configured to produce one or more of (a) a bristle having a curve along its length dimension, in response to a first offset that comprises one of a positive or a negative horizontal offset, (b) a bristle having waves along its length dimension, in response to a second offset that comprises an alternating pattern of both positive and negative horizontal offsets, and (c) a bristle having a sharp (e.g., obtuse) angle between a base portion and a tip portion thereof along its length dimension, in response to a third offset comprises a pattern of positive horizontal offsets up to a transition region, followed by a pattern of negative horizontal offsets, or vice versa. [0018] According to another embodiment, the method comprises wherein the two or more brushing guidance features and/or mechanisms of bristles include bristles having various curvatures along the length dimension thereof, and wherein the sharp (e.g., obtuse) angle between the base portion and the tip portion thereof along its length dimension comprises an angle of 90° or greater.

[0019] According to a further embodiment, the method comprises wherein the two or more brushing guidance features and/or mechanisms of bristles include bristles having various curvatures along the length dimension thereof, and further wherein the offset is on the order of 50% or less than a horizontal or vertical cross-sectional diameter of an immediately prior formed layer that the deposition material of a current layer is being deposited upon for a respective bristle being formed.

[0020] According to yet another embodiment, the method comprises wherein the bristle field further includes (a) two arrays of tall bristles curved along a length dimension thereof, positioned on exterior regions of the bristle field, with curved bristles of a first array on one side edge of the bristle field facing curved bristles of a second array on an opposite side edge of the bristle field, and (b) an array of shorter, straight bristles positioned within an interior region of the bristle field.

[0021] In another embodiment, a toothbrush features a bristle field on a brush head manufactured via the method according to the various embodiments disclosed herein. The brush head includes an elongated neck with a principal axis, wherein the bristle field is located at one end of the elongated neck and disposed perpendicular to the principal axis, and wherein the brush head is configured for being physically coupled to at an opposite end of the bristle field to the handle of the toothbrush.

[0022] The embodiments of the present disclosure advantageously solve the problem of significant difficulties in prototyping objects that have large aspect ratios (i.e., tall and thin objects), and more particularly, bristles in a brush head of a toothbrush.

[0023] Still further advantages and benefits will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description.

[0024] The embodiments of the present disclosure may take form in various components and arrangements of components, and in various steps and arrangements of steps. Accordingly, the drawings are for purposes of illustrating the various embodiments and are not to be construed as limiting the embodiments. In the drawing figures, like reference numerals refer to like elements. In addition, it is to be noted that the figures may not be drawn to scale.

[0025] Figure 1 is a perspective view of an oral healthcare personal care appliance configured for use with a removable brush head having a bristle field manufactured via a method of rapid prototyping according to an embodiment of the present disclosure;

[0026] Figures 2A and 2B are side views of tapered and end rounded bristles with a decreasing cross-sectional diameter along a length dimension of the respective bristles from a base to a tip of the respective bristles, according to an embodiment of the present disclosure;

[0027] Figure 3 is a side view of a bristle having cross-sectional diameters of various dimensions along a length dimension thereof, from a base to a tip of the respective bristle, manufactured via a method of rapid prototyping according to an embodiment of the present disclosure;

[0028] Figure 4 is a top view of a brush head with bristles of varying diameter in the bristle field, manufactured via a method of rapid prototyping according to an embodiment of the present disclosure;

[0029] Figure 5 is a perspective view of a brush head with a bristle field having a variety of both curved and straight bristles, manufactured via a method of rapid prototyping according to an embodiment of the present disclosure;

[0030] Figure 6 is a side view of a bristle having a varying curvature, in the form of a singular curve, along a length dimension thereof, from a base to a tip of the respective bristle, manufactured via a method of rapid prototyping according to an embodiment of the present disclosure;

[0031] Figure 6 A is a representational side view of a bristle having a varying curvature, showing the various regions of curvature, A-D;

[0032] Figure 7 is a side view of a bristle having a varying curvature, in the form of waves, along a length dimension thereof, from a base to a tip of the respective bristle, manufactured via a method of rapid prototyping according to an embodiment of the present disclosure;

[0033] Figure 8 is a side view of a bristle having a varying curvature, in the form of a sharp angle, along a length dimension thereof, from a base to a tip of the respective bristle, manufactured via a method of rapid prototyping according to an embodiment of the present disclosure;

[0034] Figure 9 is a side view of a bristle having cross-sectional diameters of various dimensions along a length dimension thereof, from a base to a tip of the respective bristles, in the form of periodic bulges (e.g., surface bumps and textures), manufactured via a method of rapid prototyping according to an embodiment of the present disclosure; and [0035] Figure 10 is a top view of a brush head with a variable density bristle field that includes bristles with varying density, manufactured via a method of rapid prototyping according to an embodiment of the present disclosure.

[0036] The embodiments of the present disclosure and the various features and advantageous details thereof are explained more fully with reference to the non-limiting examples that are described and/or illustrated in the drawings and detailed in the following description. It should be noted that the features illustrated in the drawings are not necessarily drawn to scale, and features of one embodiment may be employed with other embodiments as the skilled artisan would recognize, even if not explicitly stated herein. Descriptions of well-known components and processing techniques may be omitted so as to not unnecessarily obscure the embodiments of the present disclosure. The examples used herein are intended merely to facilitate an understanding of ways in which the

embodiments of the present may be practiced and to further enable those of skill in the art to practice the same. Accordingly, the examples herein should not be construed as limiting the scope of the embodiments of the present disclosure, which is defined solely by the appended claims and applicable law.

[0037] It is understood that the embodiments of the present disclosure are not limited to the particular methodology, protocols, devices, apparatus, materials, applications, etc., described herein, as these may vary. It is also to be understood that the terminology used herein is used for the purpose of describing particular embodiments only, and is not intended to be limiting in scope of the embodiments as claimed. It must be noted that as used herein and in the appended claims, the singular forms“a,”“an,” and“the” include plural reference unless the context clearly dictates otherwise.

[0038] Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which the embodiments of the present disclosure belong. Preferred methods, devices, and materials are described, although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the embodiments.

[0039] With reference now to Figure 1, a perspective view of a toothbrush 10 configured for use with a brush head 18 having a bristle field 22 comprised of multiple bristle tufts 20 manufactured via a method of rapid prototyping according to an

embodiment of the present disclosure is illustrated. If the toothbrush 10 is an electric toothbrush, it may further comprise a drive system, 12 disposed within the toothbrush. The drive system 12 operates to drive the brush head with the base 26 of the bristle tufts 20 embedded in a brush head platen 24 and the tips 28 of the bristle tufts 20 free to operate on the teeth of a user, as shown in Figure 5. .

[0040] As will become apparent from the disclosure herein, according to one embodiment, the method of rapid prototyping of a bristle field, for example, on a brush head, for an toothbrush comprises: performing, via a 3D printer, or additive manufacturing (AM), a positive layer-by-layer deposition of at least one bristle fabrication material onto a brush head platen, wherein the positive layer-by-layer deposition include deposition of the at least one bristle fabrication material in desired xyz locations according to a bristle field pattern of bristles to produce a desired bristle field. The desired bristle field includes two or more mechanisms of bristles selected from the group consisting of (i) tapered and/or end rounded bristles with a decreasing cross-sectional diameter along a length dimension of the respective bristles from a base to a tip of the respective bristles, (ii) bristles having cross- sectional diameters of various dimensions along a length dimension thereof, from a base to a tip of the respective bristles, including a pattern of the cross-sectional diameters that forms at least one of (I) a bending hinge of the respective bristles and (II) bristles with periodic bulges along the length dimension thereof, (iii) bristles having various curvatures along a length dimension thereof, from a base portion to a tip portion of the respective bristles, (iv) bristles of variable diameters in a bristle field, and (v) variable densities of bristles in a bristle field.

[0041] Current bristle fabrication materials include varieties of nylon (6-6, 6-12) or polybutylene terephthalate (PBT), a type of polyester. According to the embodiments of the present disclosure, rapid prototyping materials can include ABS, nylon, or

polycarbonate (PC), for example. With respect to toothbrush applications, one example of dimensions of a brush head platen can include a rectangular/oval type of shape with a typical width of 10 mm to 15 mm, length 10 mm to 30 mm, and thickness of 2 mm to 5 mm, although it can be appreciated that different dimensions are also possible. Dimensions of a bristle field can include a footprint that is typically the same as a platen, except for an offset, e.g., 1 mm smaller at the outer boundaries. Lastly, the height of the bristle field is determined according to the requirements of a given toothbrush implementation, for example, which can typically range from about 5 mm to 13 mm, although other dimensions are possible, and may have a complex surface topography.

[0042] The embodiments of the present disclosure advantageously provide a method to rapid prototype that comprises a positive deposition method. That is, the amount of material to be deposited during formation of a given bristle is varied, e.g., according to a given bristle function, to create a variety of tapers. Each deposition layer of a bristle can be visualized as a brick in the figures of the present disclosure. For instance, Figure 2A is one example of a bristle 30 with a steadily decreasing taper from the base 26 to the tip 28, while the illustration of Figure 2B is an“end-rounded” bristle 30 which has a very quick transition to a small diameter at the tip 28 of the bristle. Being able to rapid prototype these features saves additional manufacturing process steps and thus reduces cost and time. The material being deposited comprises any suitable bristle fabrication material for a respective bristle or respective bristles. As shown in Figure 2A, the decreasing cross-sectional diameter along the length dimension of the bristle thereof is implemented via varying a cross-sectional diameter of material deposition, between subsequent, immediately adjacent, deposition layers in a steady, continuous decreasing manner. In other words, the rate of decreasing change along a length dimension of the respective bristles from a base 26 to a tip 28 of the respective bristle remains constant, i.e., having a steadily decreasing taper. In addition, the vertical depositions, further comprise depositions of decreasing diameter or cross-sectional dimension without any overhang (i.e., in a horizontal direction) of a previously deposited layer.

[0043] As shown in Figure 2B, the decreasing cross-sectional diameter along the length dimension thereof is implemented via varying a cross-sectional diameter of material deposition between subsequent, immediately adjacent, deposition layers in an accelerated continuous decreasing manner. In other words, the rate of decreasing change along a length dimension of the bristle 30 from a base 26 to a tip 28 thereof is not constant, but increases with subsequent, immediately adjacent deposition layers. In other words, the rate of decreasing change along a length dimension of the respective bristles from a base 26 to a tip 28 of the respective bristle 30 does not remain constant, but accelerates, i.e., having a steadily larger or rapidly decreasing taper. The result is that the bristle is end-rounded at the tip 28 thereof. The vertical depositions, further comprise depositions of decreasing diameter or cross-sectional dimension without any overhang (i.e., in a horizontal direction) of a previously deposited layer. According to the embodiments of the present disclosure, bristle lengths typically vary from 5 mm to 12 mm in length from the plastic base or platen where the bristles are held. Bristle diameters for oral healthcare typically vary from 4 mil to 7 mil, or approximately 100 microns to 180 microns, although it can be appreciated that difference sizes are also possible. End rounding is smoothing the tips of the bristles that come in contact with the user’s teeth and gums, and preferably results in a hemispherical bristle tip. End rounding is typically achieves through removal of some of the original material, by means such as smoothing, sanding, grinding, etching or other removal methods. The radius of curvature for the end-rounded portions of the bristle will depend on the diameter of the bristle, and is typically half the diameter. Bristle taper typically extends from the tip to near the base of the bristle, and further can depend on the overall bristle length.

[0044] In addition, the embodiments of the present disclosure advantageously provide a method to rapid prototype that comprises a positive deposition method in which the amount of material to be deposited during formation of a given bristle is varied, e.g., according to a given bristle function. Varying the amount of material is used to create a variety of cross-sectional diameters along a length of a respective bristle. In Figure 3, each deposition layer is visualized as a discrete brick. In one embodiment, a variety of cross- sectional diameters along the length of a respective bristle 32 is useful in creating bristles with built-in“bending hinges” which advantageously allow for new bristle motions by enhancing bristle resonance. Such an embodiment also advantageously allows more energy to be targeted at the bristle tips 28, for example, so as to enhance plaque removal or to give new brushing sensations, like massage.

[0045] With reference still to Figure 3, there is shown a side view of a bristle 32 having cross-sectional diameters of various dimensions along a length dimension thereof, from a base 26 to a tip 28 of the respective bristle, manufactured via a method of rapid prototyping according to an embodiment of the present disclosure. In particular, this embodiment includes a pattern of the cross-sectional diameters that forms a bending hinge 40 of the respective bristle, i.e., the bristle is formed with a built-in hinge having a given bristle resonance. The dimensions of cross-sectional diameters of the bristle fabrication material for each respective bristle is varied along the length dimension thereof via varying a cross- sectional diameter of material deposition between subsequent, immediately adjacent, deposition layers in two or more of (a) a decreasing manner, (b) an increasing manner, and (c) an unchanging manner.

[0046] As shown in Figure 3, fabrication of the bristle 32 comprises vertical depositions with changing diameters, or cross-sectional dimensions, along a length dimension thereof. A base deposition layer 32ais deposited first. ,. At least one subsequent vertical deposition 32b with varying diameters, or cross-sectional dimensions, along a length dimension thereof is deposited. A transition region 32c operates as a pivot or vertex of the adjacent built-in hinge or bending hinge 40.

[0047] The at least one bending hinge 40 is operable to provide a desired bristle motion and resonance of the respective bristle. In one embodiment, the desired bristle motion and resonance of the respective bristle comprises a plaque removal bristle motion and resonance originating at a base of the respect bristle and being transferred, via the bending hinge 40, to a tip of the respective bristle. In addition to the plaque removal bristle motion and resonance, other specifically engineered bristle motions and resonances for an intended oral healthcare procedure are contemplated. As can be seen, deposition layers of various sizes can be used along the length of the bristle to achieve the desired performance characteristics. An example of bristle motion or resonance includes a phenomena called “bristle whip”. This is where a small motion at the base of the bristle can translate into large motions at the bristle tip. Designing a resonance, e.g., via rapid prototyping, can be used to amplify bristle motion, or could be used to reduce bristle motion to keep the bristle tip contact on a desired area. Depending on where the hinge is placed in the bristle, the bristle tip motion can be enhanced or reduced.

[0048] With reference now to Figure 4, a top view of a brush head 18 with bristles of varying diameter in the bristle field 22, manufactured via a method of rapid prototyping according to an embodiment of the present disclosure is shown. As shown, the bristle field 22 includes (a) bristles 30 of smaller cross-sectional diameter along a length dimension thereof that are positioned and distributed horizontally across a surface of a platen 24 of the brush head 18, on exterior side regions of the bristle field 22. In addition, the bristle field 22 further includes (b) bristles 32 of larger cross-sectional diameter along the length dimension thereof that are positioned and distributed horizontally across the surface of the platen 24 of the brush head 18, within an interior central region of the bristle field 22. Varying the diameter, i.e., in cross-section along a length of a bristle between different regions of the brush field, advantageously allows for a soft feeling of bristles at the gum line of a person using a toothbrush with such a bristle field and a stiff cleaning via bristles in the center of the brush field of the brush head. Various configurations of bristles as described herein in the bristle field can be used to achieve different brushing performance.

[0049] Turning now to Figure 5, a perspective view is shown of a toothbrush 10 that comprises a brush head 18 with a bristle field 22 having a variety of both curved 34 and straight 30 bristles, manufactured via a method of rapid prototyping according to an embodiment of the present disclosure. The bristles are created by the positive deposition method in which the amount of material to be deposited during formation of a given bristle is varied, e.g., according to a given bristle function. For example, the location of material deposited could be varied to advantageously create a variety of curvatures. Each deposition layer can be visualized as a discrete brick in the Figures. This could be useful in creating bristles in a curve, in a wave, or even sharp angled bristles. The bristle field 22 includes bristle tufts 20 that are arrays of tall bristles 34 curved along a length dimension thereof, positioned on exterior regions of the bristle field 22. Curved bristles of a first array on one side edge of the bristle field face curved bristles of a second array on an opposite side edge of the bristle field. The bristle field further includes bristle tufts 20 that are an array of short, straight bristles 30 positioned within an interior region of the bristle field 22.

[0050] With reference now to Figure 6, a side view is shown of a bristle 34 having a varying curvature, in the form of a singular curve, along a length dimension thereof, from a base 26 to a tip 28 of the respective bristle, manufactured via a method of rapid prototyping according to an embodiment of the present disclosure. The various curvatures along the length dimension thereof are implemented via varying an offset in a location of material deposition between subsequent, immediately adjacent, deposition layers of the bristle fabrication material for respective bristles. In one embodiment, the offset includes at least one of (a) a horizontal offset, and (b) both horizontal and vertical offsets. In particular, for the bristle of Figure 6, fabrication of the bristle begins with each of the layer-by-layer vertical depositions including one offset (i.e., a horizontal offset) for a first portion of the bristle. At a desired location, or transition region 34’, in the deposition process, the depositions include one or more of horizontal and vertical offsets.

[0051] The offset can be configured to produce a bristle having a desired curve along its length dimension, wherein the offset comprises one of a positive or a negative horizontal and/or vertical offset. In view of the above, a variety of bristles with different curvatures can be easily prototyped and/or manufactured according to the method embodiments of the present disclosure. In one embodiment, as shown in Figures 6 and 6A, the offset is on the order of 50% or less than a horizontal or vertical cross-sectional dimension or diameter of an immediately prior formed layer that the deposition material of a current layer is being deposited upon for a respective bristle being formed. According to the embodiments of the present disclosure, a curved bristle can be manufactured through slight offsets in deposition alignment. An example of this is a fishhook type of shape. The benefit to this type of bristle is that it can reach into interproximal spaces easily, which are typically difficult to access and clean. As illustrated in Figure 6, in a first section (Section A) of bristle, deposition elements would be stacked directly on top of each other. In a continuing next section (Section B) of the bristle, deposition elements would be offset horizontally by a very small amount (e.g., 5 %) and this would create a gradual curvature in the length of the bristle. In a continuing next section (Section C), the deposition offset would be a significant amount (e.g., 25%) to create a considerable amount of curvature. In a further section (Section D), the deposition offset could be reduced to zero (e.g., 0%) to create another straight section. In contrast, for current brush manufacturing technology, the bristles would be manufactured with a straight alignment, and then a secondary

heating/shaping step would have to be performed in order to bend the bristles into the desired shape.

[0052] With reference now to Figure 7, there is shown a side view of a bristle 36 having a varying curvature, in the form of waves, along a length dimension thereof, from a base to a tip of the respective bristle, manufactured via a method of rapid prototyping according to an embodiment of the present disclosure. The various curvatures along the length dimension thereof are implemented via varying an offset in a location of material deposition between subsequent, immediately adjacent, deposition layers of the bristle fabrication material for respective bristles. In one embodiment, the offset includes positive/negative (+/-) horizontal offsets 36’ between adjoining deposition layers. As shown, the bristle of Figure 7 includes waves along its length dimension, wherein the offset comprises an alternating pattern of both positive and negative horizontal offsets. In another embodiment, the offset is on the order of 50% or less than a horizontal or vertical cross- sectional dimension or diameter of an immediately prior formed layer that the deposition material of a current layer is being deposited upon for a respective bristle being formed.

[0053] Turning now to Figure 8, there is shown a side view of a bristle 38 having a varying curvature, in the form of a sharp angle 0, along a length dimension thereof, from a base 26 to a tip 28 of the respective bristle, manufactured via a method of rapid prototyping according to an embodiment of the present disclosure. The various curvatures along the length dimension thereof are implemented via varying an offset in a location of material deposition between subsequent, immediately adjacent, deposition layers of the bristle fabrication material for respective bristles. In one embodiment, the offset includes positive/negative (+/-) horizontal offsets between adjoining deposition layers of various portions of a respective bristle. As shown, the bristle of Figure 8 includes a sharp (e.g., obtuse) angle 0 between a base or first portion and a tip or second portion thereof along its length dimension. In other words, the offset comprises a pattern of positive horizontal offsets 38a for the first portion of the bristle, up to a transition region 38’, followed by a pattern of negative horizontal offsets 38b for the second portion of the bristle, or vice versa. In one embodiment, the sharp (e.g., obtuse) angle between the base portion and the tip portion thereof along its length dimension comprises an angle of 90° or greater. In another embodiment, the offset is on the order of 50% or less than a horizontal or vertical cross-sectional dimension or diameter of an immediately prior formed layer that the deposition material of a current layer is being deposited upon for a respective bristle being formed.

[0054] In another embodiment, a method to rapid prototype comprises a positive deposition method in which the size of an amount of material to be deposited during formation of a given bristle is varied, e.g., according to a given bristle function. For example, the size of material deposited could be varied to create a variety of surface bumps and textures. Such an embodiment can advantageously help with cleaning surfaces by having areas of the bristle that can“catch” the dirt or debris when the side of the bristle touches a target surface. In the Figures, each deposition layer is visualized as a discrete block.

[0055] With reference now to Figure 9, there is shown a side view of a bristle 39 having cross-sectional diameters of various dimensions along a length dimension thereof, from a base to a tip of the respective bristles, in the form of periodic bulges 39d (e.g., surface bumps and textures), manufactured via a method of rapid prototyping according to an embodiment of the present disclosure. In particular, this embodiment includes a pattern of the cross-sectional diameters that forms bristles with periodic bulges along the length dimension thereof. The dimensions of cross-sectional diameters of the bristle fabrication material for each respective bristle is varied along the length dimension thereof via varying a cross-sectional diameter of material deposition between subsequent, immediately adjacent, deposition layers in two or more of (a) a decreasing manner, (b) an increasing manner, and (c) an unchanging manner.

[0056] As shown in Figure 9, the bristle 39 with periodic bulges 39d along the length dimension thereof include surface bumps and textures that comprise vertical depositions of (i) small height, small cross-sectional diameter with zero offset depositions 39e of the at least one bristle fabrication material and (ii) large height, large cross-sectional diameter with overhang offset depositions 39d of the at least one bristle fabrication material. For example, bristles with periodic bulges could be manufactured, via rapid prototyping, with either the same material for the entire bristle, or with different materials for the bulges. If the same material is used for the entire bristle, it could give the appearance of a rope with knots periodically tied into it. This would also give additional mass throughout the length of the bristle, and thus have areas of enhanced force delivery, and thus enhanced cleaning capability. If the bulges 39d comprise alternative materials, like a soft rubber elastomeric material, the bulges could deliver a polishing or massaging effect to oral surfaces. In addition, the bulges 39d could have a texture formed on the outer surface thereof to add a roughness to what is normally a smooth surface (e.g., sides of the bristle). The textures could take many shapes and variations, such as a series of conical protrusions 86 configured to assist in scraping plaque from teeth, or a series of dome shaped bumps 88, configured to deliver a massage benefit to gums by concentrating a force delivered upon impact. [0057] In still another embodiment, a method to rapid prototype comprises a positive deposition method in which the density of bristles 20 is varied along the brush head, e.g., according to a given bristle function. For example, varying of the bristle density can provide new functional designs. Combinations of the features discussed herein are also possible. For single tuft brush heads, a maximum conformity can be obtained by using a continuous bristle field. Safety issues are non-existent, since there is very large anchor (i.e., the whole platen of the brush head). Also every bristle in the brush field of the brush head is part of a single large tuft, so the tuft retention force requirements would be easily met and corresponding tuft retention force test easily passed. In a further embodiment, varying density in the brush field according to the present embodiments advantageously allows for a soft feeling at the gum line of a person using a toothbrush with such a bristle field and a stiff cleaning via bristles in the center of the brush field of the brush head.

[0058] Turning now to Figure 10, there is shown a top view of a variable density bristle field 22 formed on platen 24, which includes bristle tufts 20 having bristles 30, 32, 34, 36, 38, 39 with varying density, manufactured via a method of rapid prototyping according to an embodiment of the present disclosure. In particular, the variable densities of bristles in a bristle field 22 comprise wherein the bristle field includes an area having lesser density of bristles 22a positioned on exterior regions of the bristle field, and (b) a greater density of bristles 22b positioned within an interior region of the bristle field.

[0059] In one embodiment, toothbrush features a bristle field on a brush head manufactured via the method according to the various embodiments disclosed herein. The toothbrush comprises a handle, wherein the brush head includes an elongated neck with a principal axis, wherein the bristle field is located at one end of the elongated neck and disposed perpendicular to the principal axis, and wherein the handle is configured for being physically coupled to at an opposite end of the elongated neck of the brush head. In a further embodiment, the toothbrush further comprises an actuator disposed within the handle and a controller. The actuator includes a drive shaft and is operable to impart a desired brushing motion, via the drive shaft, to the bristle field via the brush head. The controller is coupled to the actuator and configured for controlling an operation of the actuator to implement the desired brushing motion.

[0060] Although only a few exemplary embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of the embodiments of the present disclosure. Accordingly, all such modifications are intended to be included within the scope of the embodiments of the present disclosure as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures.

[0061] In addition, any reference signs placed in parentheses in one or more claims shall not be construed as limiting the claims. The word“comprising” and“comprises,” and the like, does not exclude the presence of elements or steps other than those listed in any claim or the specification as a whole. The singular reference of an element does not exclude the plural references of such elements and vice-versa. One or more of the embodiments may be implemented by means of hardware comprising several distinct elements, and/or by means of a suitably programmed computer. In a 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 an advantage.