Toothbrush

Abstract

The present application provides a toothbrush capable of having both comfortable massage feeling and gap cleaning feeling. The toothbrush comprises: a brush head portion having a bristle planting surface; and a plurality of bristle planting portions provided on the bristle planting surface in a single tuft independent surface shape in a front view angle observed from a front surface side opposite to the bristle planting surface. The bristle planting portion has: a central tuft arranged in a central region of the bristle planting surface; and a plurality of peripheral tufts spaced apart from the central tuft and surrounding the central tuft at intervals. In an outline profile of the central tuft in the front view angle, a recessed portion recessed in a direction away from the peripheral tuft is formed at a position opposite to at least one of the peripheral tufts. The peripheral tuft opposite to the recessed portion is partially entered into the recessed portion when the peripheral tuft is deflected by an external force.

Description

Technical Field

[0001] This invention relates to toothbrushes. Background Technology

[0002] As a method for manufacturing toothbrushes, known methods include inserting bristle bundles into multiple bristle holes pre-formed on the bristle-embedding surface of the head and fixing them with flat threads. Additionally, methods for fixing bristle bundles to the head by thermoforming and methods based on in-mold injection molding are known (e.g., Patent Document 1). According to these methods, there are advantages such as the ability to fix bristle bundles without using flat threads, and thus the ability to implant bristle bundles of various cross-sectional shapes.

[0003] To enhance the comfortable massage sensation on the gums while brushing, increasing the area of ​​the bristles in contact with the gums is effective. One method is to use bristles with large pores and high density.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 11-075940

[0007] The technical problem that the invention aims to solve

[0008] However, conventional large-pore, high-density bristles have the following problems: the bristle tufts are rigid and not easily bent, resulting in stronger pressure on the gums and making it difficult to achieve a comfortable massage sensation. Additionally, while they easily reach the tooth surface, the bristles do not easily penetrate narrow spaces such as between teeth and at the neck of the tooth, thus failing to provide a sufficient cleaning sensation. Therefore, to improve the cleaning sensation in interdental spaces, methods have been used to reduce the area of ​​each bristle tuft by connecting multiple small pores to form larger bristle tufts. However, this results in excessive bristle bending, which impairs the massage sensation. Summary of the Invention

[0009] This invention was made in consideration of the above problems, and its purpose is to provide a toothbrush that can provide both a comfortable massage sensation and a thorough cleaning sensation.

[0010] Technical means for solving technical problems

[0011] The present invention has the following aspects. [1]

[0013] A toothbrush, wherein:

[0014] The brush head has a bristle-embedded surface; and

[0015] Multiple hair grafting sections, viewed from the frontal side opposite to the hair grafting surface, are arranged as individual hair tufts on the hair grafting surface.

[0016] The plurality of hair-embedded sections include:

[0017] A central hair tuft, disposed in the central region of the hair-planting surface; and

[0018] Multiple peripheral hair tufts, which are spaced apart from the central hair tuft and surround the central hair tuft at intervals.

[0019] In the frontal view of the central hair tuft, at a position opposite to at least one of the peripheral hair tufts, there is a recess that is concave in a direction away from that peripheral hair tuft.

[0020] When the hair tufts in the surrounding hair tufts are bent by external force, a portion of the opposing hair tufts that are opposite the depression enter the depression. [2]

[0022] According to the toothbrush described in [1], wherein,

[0023] The shortest distance between the opposing hair tuft and the depression is less than 0.5 mm. [3]

[0025] According to the toothbrush described in [1] or [2], wherein,

[0026] The opposing hair tufts have protrusions that are opposite to the depression and taper toward the depression. [4]

[0028] According to the toothbrush described in [3], wherein,

[0029] In the frontal view, the protrusion is an arc with radius r, and has a center of curvature on the side opposite to the depression.

[0030] In the frontal view, the radius of the virtual circle connecting one end of the concave outline and the other end, at the position furthest from the protrusion in the opposite direction of the opposing hair tuft and the concave, is greater than or equal to the radius r. [5]

[0032] According to any one of [1] to [4], the toothbrush, wherein,

[0033] The recess is provided on the outline of the central hair tuft extending along the long axis in the frontal view. [6]

[0035] According to the toothbrush described in [5], wherein,

[0036] At least two of the peripheral hair tufts have a second recess in the outline of the shape in the frontal view, on the side opposite to the side facing the central hair tuft.

[0037] The second recess is configured to be axially symmetrical with respect to a centerline located at the center of the short axis of the central hair tuft and extending along the long axis. [7]

[0039] According to the toothbrush described in [5] or [6], wherein,

[0040] The opposing hair tufts sandwich the central hair tuft and are respectively arranged on both sides of the minor axis of the central hair tuft.

[0041] The first non-opposite hair tuft, which is not opposite to the depression, sandwiches the central hair tuft and is respectively arranged on both sides of the long axis direction.

[0042] The second non-opposite hair tufts in the peripheral hair tufts, which are not opposite to the depression, are sandwiched between the central hair tufts and are respectively arranged on both sides of an inclined direction that intersects both the major axis direction and the minor axis direction.

[0043] The opposing hair tufts taper towards the central hair tuft.

[0044] At least one of the first non-opposite hair tuft and the second non-opposite hair tuft tapers toward the central hair tuft. [8]

[0046] According to any one of [1] to [7], the toothbrush, wherein,

[0047] The non-opposite hair tufts in the peripheral hair tufts that are not opposite the depression but adjacent to the opposite hair tufts have protrusions that taper toward the central hair tuft.

[0048] The central hair tuft has a protrusion at a position opposite to the protrusion.

[0049] The effects of the invention

[0050] In this invention, a toothbrush is provided that can provide both a comfortable massage sensation and a thorough cleaning sensation. Attached Figure Description

[0051] Figure 1 This is a partial front view of the toothbrush 1 according to the first embodiment.

[0052] Figure 2 This is a magnified view of the area surrounding the central hair tuft 20.

[0053] Figure 3 This is a partial front view of the toothbrush 1 according to the second embodiment. Detailed Implementation

[0054] The following is for reference Figures 1 to 3 An embodiment of the toothbrush of the present invention will be described.

[0055] Furthermore, the following embodiments illustrate one aspect of the present invention and do not limit the invention; modifications can be made freely within the scope of the technical concept of the present invention. Additionally, in the following drawings, for ease of understanding of the structures, the scale, quantities, etc., of each construction differ from the actual construction.

[0056] [First Implementation of a Toothbrush]

[0057] Figure 1 This is a partial front view of the toothbrush 1 according to the first embodiment. Figure 2 This is a magnified view of the area surrounding the central hair tuft 20, which will be described later.

[0058] like Figure 1 and Figure 2 As shown, the toothbrush 1 has: a brush head 3 with a bristle-embedded surface 2, and a handle 4 connected to the brush head 3. The brush head 3 has a bristle-embedded surface 2 on its front side. The brush head 3 is located along the long axis of the handle 4 (in the direction of the long axis). Figure 1 The front side (in the vertical direction).

[0059] In the following description, the direction parallel to the hair-planting surface 2 and orthogonal to the long axis direction (in...) Figure 1 In the text, the left and right directions are used as the width direction for explanation. Sometimes, the width direction is used as the width direction. Figure 1 The left side is called the width side. Figure 1 The right side is referred to as the other side in the width direction. Furthermore, the side opposite to the bristle-embedded surface 2 will be appropriately described as the front side, and the side opposite to the front side as the back side. Regarding the long axis direction, the side where the brush head 3 is disposed relative to the brush handle portion 4 will be designated as the front end side, and the side where the brush handle portion 4 is disposed will be designated as the rear end side.

[0060] The brush head 3 extends along its long axis in a frontal view, and is, for example, a long oval (stadium) shape. The shape of the brush head 3 in the frontal view is not limited to a long oval shape; it can be any shape such as an ellipse or rectangle. The brush head 3 has multiple bristle-embedded sections 10 on the bristle-embedded surface 2. Each bristle-embedded section 10 is configured as a surface with an independent individual bristle bundle.

[0061] The hair grafting section 10 has a central hair tuft 20 and multiple peripheral hair tufts 30.

[0062] A central hair tuft 20 is positioned in the central region 10A of the hair-planting surface 2. Peripheral hair tufts 30 are arranged at intervals from the central hair tuft 20. Multiple peripheral hair tufts 30 are arranged around the central hair tuft (in... Figure 1 (There are 8 in the middle). The surrounding hair tufts are arranged at intervals.

[0063] The central bristle tuft 20 is an elongated circle with its major axis oriented as its major diameter in a frontal view. That is, the maximum dimension of the central bristle tuft 20 in the major diameter direction is longer than the maximum dimension in the minor diameter direction. The center of the central bristle tuft 20 in the minor diameter direction is located at the same position as the center line J located in the width direction of the toothbrush 1 and extending along the major axis direction.

[0064] The central hair tuft 20 has a recess 21 and a protrusion 22. The recess 21 is located opposite at least one of the peripheral hair tufts 30. In a frontal view, the recess 21 is located in the outline of the central hair tuft 20 extending along its long axis. The recesses 21 are respectively located on both sides of the outline along its short axis. The recesses 21 are recessed in a shape that protrudes inward in the short axis direction and is recessed inward in the short axis direction. The recess 21 is an arcuate shape with a center of curvature on the outer side in the short axis direction. The recess 21 may also be a shape with a straight portion.

[0065] The recess 21 preferably intersects with the apex of the central hair tuft 20. That is, the recess 21 is preferably formed to intersect with the apex of the arc portion and the straight portion of the virtual elongated circle where no recess 21 is formed.

[0066] To facilitate torsional behavior through contact between the protrusion 22 of the central hair tuft 20 and the peripheral hair tuft 30, a thin-walled protrusion 22 is more effective. Therefore, the central hair tuft 20 is preferably recessed from its apex.

[0067] The protrusion 22 is formed by arcs that extend outward from both ends of the long axis of the elongated central hair tuft 20. The protrusion 22 includes: an arc that extends outward in a frontal view, and a chamfer r formed at the intersection with the arc that forms the outer contour of the recess 21.

[0068] In the protrusion 22, in the intersection area where it intersects with the recess 21, the angle between the arc of the protrusion 22 and the arc forming the recess 21 is small. Therefore, it is thinner compared to other parts of the central bristle tuft 20 and is more prone to bending under applied force during brushing. Thus, for example, when brushing the occlusal surface, it maintains a realistic feeling of plaque removal and allows for a more undulating brushing motion, improving cleaning power.

[0069] Furthermore, regarding the bristle tips of the central bristle tuft 20, in the case of a multi-peak profile where the central bristles are the tallest and the bristles on the edge sides are the shortest, making them less prone to bending. Therefore, by providing a recess 21 on the edge side of the bristle tuft, the bristles can bend more easily, thereby maintaining cleaning force, such as a realistic feeling of removing surface plaque when brushing the occlusal surface, and enabling a convex-concave brushing motion.

[0070] The peripheral hair tuft 30 includes opposing hair tufts 40, a first non-opposing hair tuft 50, and a second non-opposing hair tuft 60. The opposing hair tufts 40 are spaced apart on both sides of the central hair tuft 20 in the minor axis direction. The opposing hair tufts 40 are opposite the recess 21 in the minor axis direction. That is, the recess 21 is recessed away from the opposing hair tufts 40 in the peripheral hair tuft 30. The opposing hair tufts 40 are approximately triangular in shape, with their maximum length in the major axis direction gradually decreasing towards the central hair tuft 20 from the outside in the minor axis direction.

[0071] like Figure 2 As shown, the opposing bristle tuft 40 has a protrusion 41 at its inner end in the minor axis direction. The protrusion 41 is an arc shape with a center of curvature on the side opposite to the recess 21 in a frontal view. The protrusion 41 is an arc shape that is opposite to the recess 21 and tapers towards the recess 21. When the opposing bristle tuft 40 is bent by an external force, a portion of it (the protrusion 41) enters the recess 21. When the opposing bristle tuft 40 moves along the minor axis direction under the applied external force during brushing, a portion of its outline, namely the protrusion 41, enters the recessed region 21a without interfering with the outline of the central bristle tuft 20 and the opposing bristle tuft 40. The recessed region 21a is the area surrounded by the arc forming the outline of the recess 21 and the line segment connecting one end of the arc to the other end.

[0072] If the gaps between the bristles narrow, the area becomes denser, thus improving the massage feel. On the other hand, if the bristles in the bristles are not easily bent, the cleaning feel may be reduced. By having a recess 21 in the central bristle 20 and having the opposing bristle 40 enter the recess 21, it is possible to set a region that is easy to bend (the intersection of the protrusion 22 and the recess 21) and maintain high density, thereby achieving both a massage feel and cleaning power.

[0073] Furthermore, with the central hair tuft 20 having a depression 21 and the peripheral hair tufts 30 having a shape that allows them to enter the depression 21, the bending of one hair tuft can easily achieve contact with another hair tuft, changing the directionality of the bending. Therefore, in addition to the complex bending originating from the shapes of each hair tuft, the massage sensation of the gums can be further enhanced.

[0074] Furthermore, depending on the direction of the hair tuft's bending, it can perform the same action as a hair tuft or not when entering the depression, thus maintaining a high density. Moreover, the user can perceive the shape of each hair tuft and actually feel the different actions of each hair tuft for massage.

[0075] Specifically, when massaging the gums with the entire brush head 3 after brushing, the central bristle tuft 20 and the peripheral bristle tuft 30 move together and combine to produce the bending and twisting of the bristles, thereby further enhancing the massage sensation.

[0076] Preferably, if the radius of the protrusion 41 is set to r, then the radius R of the virtual circle (in this embodiment, the arc forming the outer contour of the recess 21) connecting one end of the arc forming the outer contour of the recess 21, the other end of the arc, and the position furthest from the protrusion 41 in the opposite direction of the opposing hair bundle 40 and the recess 21 is greater than or equal to the radius r.

[0077] By using a radius R greater than or equal to a radius r, the opposing hair tufts 40 can enter the depression 21, maintaining high density and enhancing the massage sensation.

[0078] Furthermore, the longer the width of the hair tuft, the less easily the hair tuft moves in that direction. Therefore, by providing a recess 21 on the outline of the central hair tuft 20 that extends along the long axis in a frontal view, the protrusion 22 is flexed (twisted) along the circumferential direction of the arc, starting from the most recessed part of the recess 21. This achieves high density and promotes the flexing of the hair tuft in the direction of its width.

[0079] Therefore, it can maintain the feeling of removing surface plaque while brushing the occlusal surface, and can perform concave and convex brushing, thus achieving both a massage-like feel and cleaning power.

[0080] The shortest distance t between the opposing hair bundle 40 and the depression 21, i.e. the shortest distance t between the protrusion 41 and the depression 21, is preferably less than 0.5 mm.

[0081] When the shortest distance t exceeds 0.5 mm, even if the opposing bristle tufts 40 enter the recess 21 under the applied external force during brushing, insufficient contact may still occur, resulting in an inadequate massage sensation. By setting the shortest distance t to 0.5 mm or less, sufficient contact is achieved when the opposing bristle tufts 40 enter the recess 21, thereby improving the massage sensation.

[0082] Two first non-opposite hair tufts 50 are positioned on either side of the central hair tuft 20 along the long axis. The first non-opposite hair tufts 50 are not opposite the recess 21. Four second non-opposite hair tufts 60 are positioned on either side of the central hair tuft 20 along an inclined direction intersecting both the long and short axis directions. The second non-opposite hair tufts 60 are not opposite the recess 21.

[0083] The second non-opposite hair tuft 60 in the peripheral hair tuft 30, which is adjacent to the opposite hair tuft 40, has a protrusion 61 that tapers toward the central hair tuft. The protrusion 61 is opposite to the convex portion 22.

[0084] By positioning the protrusion 61 opposite the convex portion 22, the second non-opposed bristle tuft 60 efficiently makes point-to-point contact with the convex portion 22 of the central bristle tuft 20. This promotes the torsional behavior of the convex portion 22, maintains the massage sensation, and enhances the cleaning sensation.

[0085] The peripheral hair tufts 30, which include opposing hair tufts 40, first non-opposing hair tufts 50, and second non-opposing hair tufts 60, taper toward the central hair tuft 20. Relative to the central hair tuft 20, there are peripheral hair tufts 30 surrounding it, and these peripheral hair tufts 30 taper toward the central hair tuft 20, thus the highest density area formed by the contact between the central hair tuft 20 and the peripheral hair tufts 30 is prone to bending.

[0086] Furthermore, by positioning the opposing bristle tufts 40 that enter the recess 21 on both sides of the central bristle tuft 20 in the width direction, the protrusion 61 contacts and twists with the central bristle tuft 20, thus maintaining a massage sensation and improving the cleaning sensation. Moreover, by arranging opposing bristle tufts 40, the first non-opposing bristle tufts 50, and the second non-opposing bristle tufts 60 of different shapes around the central bristle tuft 20, the flexing of various bristles can be felt at the gum line, generating a massage sensation. Additionally, by tapering the peripheral bristle tufts 30 towards the central bristle tuft 20, the flexing distribution of the bristle tufts is increased in shape, improving the twisting effect compared to cases without a tapering shape.

[0087] At least two of the peripheral hair tufts 30 have a second recess on the side opposite to the side facing the central hair tuft in the outline of the hair tuft from a frontal view. In this embodiment, the opposing hair tuft 40 has a second recess 42, and the first non-opposing hair tuft 50 has a second recess 51. The second recesses 42 and 51 are respectively axially symmetrical with respect to the center line J.

[0088] When the central hair tuft 20 and the peripheral hair tuft 30 are integrated through the recess 21 of the central hair tuft 20 and the protrusion 41 of the opposing hair tuft 40, and the hair tufts move, the outer recesses of the opposing hair tuft 40 and the first non-opposing hair tuft 50 increase the ease of bending, thereby achieving both a cleaning feel and a massaging feel. In addition, the second recess 42 and the second recess 51 are configured axially symmetrically with respect to the center line J, thereby making it easier to perceive the shape of the hair tufts, for example, further enhancing the feeling of the gingiva being enveloped.

[0089] Preferably, the second recess 42 forms the outermost contour of the opposing hair tuft 40 in the short axis direction, and is partially recessed. Preferably, the maximum size of the second recess 42 in the long axis direction is less than 50% of the maximum size of the opposing hair tuft 40 in the long axis direction. Preferably, the maximum size of the second recess 42 in the long axis direction is shorter than the maximum size of the outer contour line (protrusion 41) near the central hair tuft 20 in the long axis direction.

[0090] The opposing hair tuft 40 has a second recess 42 on the outer side and a protrusion 22. By leaving the outermost contour line as is different from the central hair tuft 20 and making a portion recessed, the shape of the hair tuft is not easily destroyed. By maintaining the shape of the hair tuft, the massage effect of the gums can be improved by utilizing the surface derived from the shape of the hair tuft.

[0091] Preferably, the second recess 51 forms the outermost contour of the first non-opposed hair tuft 50 in the long axis direction, with a portion recessed. More preferably, the maximum size of the second recess 51 in the short axis direction is less than 50% of the maximum size of the first non-opposed hair tuft 50 in the short axis direction. Preferably, the maximum size of the second recess 51 in the short axis direction is shorter than the outer contour line near the central hair tuft 20. The first non-opposed hair tuft 50 has a second recess 51 on its outer side. By differentiating the opposing hair tuft 40 and the first non-opposed hair tuft 50 from the central hair tuft 20, leaving the outermost contour line and partially recessed, the hair tuft shape is less likely to be destroyed. By maintaining the hair tuft shape, the massage effect on the gums can be improved by utilizing the surface derived from the hair tuft shape.

[0092] Preferably, the depth of the second recess 42 is shorter than the straight-line distance of the non-recessed portion of the outermost contour of the outermost part of the opposing hair tuft 40 in the minor axis direction, and more preferably longer than the depth of the recess 21 of the central hair tuft 20. Preferably, the depth of the second recess 51 is shorter than the straight-line distance of the non-recessed portion of the outermost contour of the outermost part of the outermost part of the major axis direction of the first non-opposing hair tuft 50, and more preferably longer than the depth of the recess 21 of the central hair tuft 20.

[0093] The protrusions created by the second recess 42 in the opposing hair tuft 40 and the protrusions created by the second recess 51 in the first non-opposing hair tuft 50 are less prone to torsion caused by contact with other hair tufts compared to the central hair tuft 20. Therefore, by deepening the recess depth, they are made easier to bend.

[0094] like Figure 1 As shown, the curve or line segment L that preferably forms the recess 21 of the central hair tuft 20 overlaps with the line segment of the second non-opposite hair tuft 60 near the opposite hair tuft 40 when extended. More preferably, the widths of the first groove 71 between the opposite hair tuft 40 and the second non-opposite hair tuft 60 and the second groove 72 between the central hair tuft 20 and the opposite hair tuft 40 are the same.

[0095] By overlapping the line segment of the second non-opposite hair tuft 60 near the opposing hair tuft 40 at the extension line L, the second non-opposite hair tuft 60 and the protrusion 22 of the central hair tuft 20 can make more efficient contact, thereby promoting the torsional behavior of the protrusion 22. In addition, by making the widths of the first groove 71 and the second groove 72 the same, even if each hair tuft performs complex movements individually, they can be integrated into a whole texture, improving the massage sensation.

[0096] The peripheral hair tufts 30, which interact with the central hair tuft 20, are easily bent, so from the viewpoint of promoting the torsional behavior of the protrusions 22 generated by the recesses 21, it is preferable that the area of ​​the central hair tuft 20 in the hair-planted portion 10 is the largest in the frontal view.

[0097] The area of ​​the first non-opposite hair tuft 50 in the peripheral hair tuft 30 that does not enter the depression 21 and is not located in the extension direction of the line L associated with the depression 21 is the largest.

[0098] Therefore, the presence of relatively large and non-bending bristle tufts allows for a variety of bending characteristics within a single brush head 3, thereby improving cleaning power.

[0099] That is, by using at least two types of peripheral bristle tufts 30 to surround the central bristle tuft 20, a complex flexing behavior is achieved, which can achieve both cleaning power (tooth surface, small gaps) and massage sensation.

[0100] Examples of bristles constituting the central bristle tuft 20 and the peripheral bristle tuft 30 include straight bristles, bristles with a diameter gradually decreasing towards the bristle tip (conical bristles), bristles with bifurcated tips, spiral bristles, and bristles with irregular cross-sections. From the perspective of cleaning effectiveness around the orthodontic appliance and at the neck of the teeth, conical bristles are preferred for constituting the bristle tuft. By making the bristles conical, brushing force can be ensured and the bristle tips can reach even finer areas, thus improving the cleaning effect. Examples of bristle tip shapes include flat, mountain-shaped, convex, and concave. By making the bristle tip shape mountain-shaped or hill-shaped, the bristle tips can reach even finer areas, thus improving the cleaning effect.

[0101] The material of the bristles in the aforementioned bristles is not particularly limited, but examples include polyamides (e.g., nylon 6 / 12, nylon 6 / 10), polyesters (e.g., polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate), polyolefins (e.g., polypropylene), and elastomers (e.g., olefin-based, styrene-based) and other synthetic resin materials. Furthermore, multiple combinations of these resin materials can be used; for example, different resin materials can be used in the core and sheath, similar to a core-sheath structure.

[0102] The diameter of the bristles constituting the bristle bundles described above is, for example, 4 to 7 mil (1 mil = 1 / 1000 inch = 0.025 mm). A diameter of 4 mil or more ensures sufficient bristle stiffness for effective cleaning of the neck of the tooth, while a diameter of 7 mil or less ensures sufficient softness to gently irritate the gums, etc. Furthermore, the diameter of the bristles in the conical bristles is the same as the diameter at the base.

[0103] The material of the brush handle 4 is not particularly limited, but polypropylene (PP) resin, polyacetal (POM) resin, polybutylene terephthalate (PBT) resin, polyethylene terephthalate (PET) resin, etc. are preferred.

[0104] As a method for fixing the central bristle 20 and the peripheral bristle 30 to the bristle implantation surface 2, the following methods can be used: a heat-fusion method (pressure-temperature-time (PTt) method) in which the molten part at the lower end of the bristle 3 is pressed into and fixed in the molten resin that becomes the brush head 3; and an in-mold injection method in which the brush head is formed by injecting molten resin into a mold after heating the lower end of the bristle 20 to form a molten block.

[0105] As described above, in the toothbrush 1 of this embodiment, a recess 21 is provided at the position where the central bristle 20 and the opposing bristle 40 are opposite each other. This recess is recessed in the outer contour in a direction away from the opposing bristle 40. The thin-walled portion of the central bristle 20 is easily flexible, which can maintain the feeling of plaque removal and can perform uneven brushing, thus improving cleaning power. In addition, in the toothbrush 1 of this embodiment, when the opposing bristle 40 in the peripheral bristle 30 opposite the recess 21 is bent by external force, some of it enters the recess 21. Therefore, the gap between the bristles becomes narrower and denser, thus improving the feeling of massage.

[0106] Therefore, in the toothbrush 1 of this embodiment, both a comfortable massage sensation and a cleansing sensation can be achieved.

[0107] [Second Implementation of a Toothbrush]

[0108] Next, refer to Figure 3 The second embodiment of toothbrush 1 will be described.

[0109] In this diagram, for and Figures 1 to 2 Elements that are identical to those in the first embodiment shown are labeled with the same symbols, and their descriptions are omitted.

[0110] In the second embodiment, the number and shape of the recesses 21 and protrusions 41 are different from those in the first embodiment.

[0111] Figure 3 This is a partial front view of the toothbrush 1 according to the second embodiment.

[0112] In this embodiment, the central hair tuft 20 has an outer profile formed by straight lines that taper outwards from both ends in the long axis direction. Two recesses 21 are provided on each side of the central hair tuft 20 in the short axis direction, for a total of four. On each side in the short axis direction, the recesses 21 are spaced apart in the long axis direction. The outer profiles of the recesses 21 are formed by straight lines that taper inwards towards the short axis direction.

[0113] The opposing hair tuft 40 has two protrusions 41. The two protrusions 41 are respectively positioned opposite to the two recesses 21 on one side of the central hair tuft 20 in the minor axis direction.

[0114] The other structures are the same as those in the first embodiment described above.

[0115] In the toothbrush 1 with the above structure, the portion of the thin wall intersecting the outer contour on the outer side of the two recesses 21 arranged in the long axis direction is increased, so it is easy to bend when subjected to applied external force during brushing. In addition, by increasing the number of recesses 21 formed in the central bristle tuft 20, the protrusions 41 enter the recesses 21, and the bristle tuft becomes denser.

[0116] Therefore, in the toothbrush 1 of this embodiment, in addition to obtaining the same function and effect as the first embodiment described above, a stronger massage sensation and cleaning power can be found.

[0117] The above is with reference to the appendix. Figure 1 The preferred embodiments of the present invention have been described, but the present invention is by no means limited to these examples. The shapes, combinations, etc. of the constituent components shown in the above examples are just examples, and various changes can be made based on design requirements, etc., without departing from the spirit of the present invention.

[0118] For example, in the above embodiment, a structure is illustrated in which the long axis direction of the central bristle tuft 20 is aligned with the long axis direction of the toothbrush 1, and the short axis direction of the central bristle tuft 20 is aligned with the short axis direction of the toothbrush 1, but this structure is not limited to this one. Alternatively, the structure could also have the long axis direction of the central bristle tuft 20 aligned with the short axis direction of the toothbrush 1, and the short axis direction of the central bristle tuft 20 aligned with the long axis direction of the toothbrush 1.

[0119] Furthermore, the shapes of the recess 21 and protrusion 41 shown in the above embodiment are one example. If a portion of the opposing hair bundle 40 enters the shape of the recess 21 when it is bent by an external force, various other shapes can be selected.

[0120] Symbol Explanation

[0121] 1. Toothbrush

[0122] 2 hair transplanted surface

[0123] 3. Brush the head

[0124] 4. Brush handle

[0125] 10 Hair transplantation department

[0126] 10A Central Area

[0127] 20 central tuft

[0128] 21. Depression

[0129] 22 convex part

[0130] 30 Peripheral hair tufts

[0131] 40 Opposite hair bundles

[0132] 41. Protrusion

[0133] 42 Second Depression

[0134] 50 First non-opposite hair tuft

[0135] 60 Second non-opposite hair tuft

[0136] 61. Protrusion

Claims

1. A toothbrush, wherein, have: The brush head has a bristle-embedded surface; and Multiple hair grafting sections are arranged on the hair grafting surface in a planar manner with individual hair bundles in a frontal view viewed from the frontal side opposite to the hair grafting surface. The plurality of hair-embedded sections include: A central hair tuft, disposed in the central region of the hair-planting surface; and Multiple peripheral hair tufts, which are spaced apart from the central hair tuft and surround the central hair tuft at intervals. In the frontal view of the central hair tuft, at a position opposite to at least one of the peripheral hair tufts, there is a recess that is concave in a direction away from that peripheral hair tuft. When the hair tufts in the surrounding hair tufts are bent by external force, a portion of the opposing hair tufts that are opposite the depression enter the depression.

2. The toothbrush according to claim 1, wherein, The shortest distance between the opposing hair tuft and the depression is less than 0.5 mm.

3. The toothbrush according to claim 1, wherein, The opposing hair tufts have protrusions that are opposite to the depression and taper towards the depression.

4. The toothbrush according to claim 3, wherein, In the frontal view, the protrusion is an arc with radius r and has a center of curvature on the side opposite to the recess. In the frontal view, the radius of the virtual circle connecting one end of the concave outline and the other end, at the position furthest from the protrusion in the opposite direction of the opposing hair tuft and the concave, is greater than or equal to the radius r.

5. The toothbrush according to any one of claims 1 to 4, wherein, The recess is provided on the outline of the central hair tuft extending along the long axis in the frontal view.

6. The toothbrush according to claim 5, wherein, At least two of the peripheral hair tufts have a second recess on the opposite side of the side facing the central hair tuft in the outline of the shape viewed from the front. The second recess is configured to be axially symmetrical with respect to the centerline located in the short axis direction of the central hair tuft and extending along the long axis direction.

7. The toothbrush according to claim 5, wherein, The opposing hair tufts sandwich the central hair tuft and are respectively arranged on both sides of the minor axis of the central hair tuft. The first non-opposite hair tuft, which is not opposite to the depression, sandwiches the central hair tuft and is respectively arranged on both sides of the long axis direction. The second non-opposite hair tufts in the peripheral hair tufts, which are not opposite to the depression, are sandwiched between the central hair tufts and are respectively arranged on both sides of an inclined direction that intersects both the major axis direction and the minor axis direction. The opposing hair tufts taper towards the central hair tuft. At least one of the first non-opposite hair tuft and the second non-opposite hair tuft tapers toward the central hair tuft.

8. The toothbrush according to any one of claims 1 to 4, wherein, The non-opposite hair tufts in the peripheral hair tufts that are not opposite the depression but adjacent to the opposite hair tufts have protrusions that taper toward the central hair tuft. The central hair tuft has a protrusion at a position opposite to the protrusion.

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